Whale Pelvic Bones | Berean Archive

"Nothing can be imagined more useless to the animal than rudiments of hind legs entirely buried beneath the skin of a whale, so that one is inclined to suspect that these structures must admit of some other interpretation. Yet, approaching the inquiry with the most skeptical determination, one cannot help being convinced, as the dissection goes on, that these rudiments really are femur and tibia." — John Struthers, dissecting bowhead whales, 1881¹

"Our study suggests that far from being mere relics of a terrestrial past, cetacean pelvic bones are targets of sexual selection." — James Dines and colleagues, Evolution, 2014²

Summary

The parent article, Vestigial Structures, separates two claims: that an organ is useless, and that it is a reduced copy of something larger in an ancestor. The whale pelvis is the case where the two claims come apart most cleanly, because the bones have a measured function and are, by every anatomical description since 1881, reduced.

What the bones are. Every living whale and dolphin except the pygmy and dwarf sperm whales carries a pair of bones in the belly wall, in front of the anus, that touch no other bone.² In a 3 m bottlenose dolphin they are about 11 cm long;² in bowheads of 15 to 19 m about 38 to 51 cm.¹ In males the crura of the penis and the ischiocavernosus muscles attach to them; in females the same muscles run to the clitoris.² Some baleen whales also carry a buried femur, and the bowhead a tibia.³
The function is real and measured. Dines and colleagues scanned 130 pelvic bones from 29 species and found that species with relatively large testes, the standard proxy for competitive mating, have relatively large pelvic bones and penises, while the first rib, used as a control, shows no such pattern.² The paper rejects the label "useless vestiges."²
The same paper calls the pelvis "highly reduced." Its first sentence about the bones says whales "lost external hind limbs and evolved a highly reduced pelvis which seems to serve no other function except to anchor muscles that maneuver the penis."² Function and reduction are both true in the same study, and the functionless reading was already retired inside the mainstream literature in 1990.⁴
Embryos start a leg and stop. Dolphin embryos grow a hind-limb bud with a working apical ridge for a few days, then the bud degenerates because the signalling genes Hand2 and Sonic hedgehog never switch on in it.⁵ Mice engineered to lack Shh keep the same rump of limb skeleton buried in the body wall.⁵
A few whales grow legs. A 1919 humpback had two 127 cm protrusions containing a femur, tibia, ankle and metatarsal in the right order;⁶ a 1956 sperm whale, a 1963 dolphin and two Taiji dolphins in 2006 and 2023 carried smaller paired hind appendages.⁷ These are rare, about one in ten thousand in the one counted population,⁸ and both sides read them through a prior on ancestry.
The creationist literature answers the wrong claim. Wieland, Bergman, Thomas, Guliuzza, Engler and the Answers in Genesis pages all argue that the bones have a function and are therefore not vestigial, which answers the 1936 textbook claim, not the modern one.⁹ Two creationist sources engage the live argument: Surtees in 2024 denies the homology, and Wise in 1995 and Wieland in 2006 concede latent hind-limb information within the kind.¹⁰

Verdict: the whale pelvis is a functional vestige. It anchors the reproductive muscles, and it is a detached, socketless, sexually selected remnant of a hip that once carried a leg. The creationist side has won the argument that the bones are not useless and has not yet answered the argument that they are reduced homologues, which the embryos, the atavisms and the fossil series each support. The honest young-earth position is Wise's: the information for a hind limb is still in the genome, and what remains to be explained is why.

Part 1: What the bones are

Tajima, Hayashi and Yamada, dissecting three finless porpoises in 2004, describe the pelvic bones of modern cetaceans as "a pair of slender rod-like structures within the abdominal wall muscles just anterior to the anus with no articulations to the axial skeleton," in both sexes.¹¹ Gingerich, Smith and Simons wrote in Science in 1990 that living cetaceans "lack hind limbs entirely, retaining only rod-like vestiges of pelvic bones, femora, and rarely tibiae embedded in musculature of the ventral body wall."⁴

The bones are small against the animal. Dines and colleagues' scanned bottlenose dolphin pelvic bones are "approximately 11 cm long" on an adult male of about 3 m, so under 4 percent of body length.² Struthers measured the bone in eleven bowheads: about 15 inches in a 62-foot female and almost 20 inches in a 48-foot male, that is 38 to 51 cm on animals of 15 to 19 m, or 2 to 3.5 percent.¹ Andrews gave the humpback's as "slender ossifications about 6 or 8 inches in length."⁶

What the bones lack is as telling as what they keep. Dines and colleagues summarise the anatomy: cetacean pelves "no longer contact the vertebral column, have lost their acetabulum and obturator foramen, and evolved to such small size that there is still no general consensus as to which of the three fused bones found in their terrestrial ancestor (ischium, ilium and/or pubis) they derive from."² No hip socket, no hole for the obturator nerve, no joint with the sacrum. Two species have gone further: the pygmy and dwarf sperm whales, Kogia breviceps and K. sima, "appear to have replaced their pelvic bones with functional cartilaginous sheets," so that "all 92 extant cetacean species except two" retain the bones.²

Baleen whales keep more. Senter and Moch's 2015 survey of vestigial bones in mammal skeletons summarises the literature: "the bowhead whale (Balaena mysticetus) retains the femur and tibia; the humpback (Megaptera novaeangliae) and fin whale (Balaenoptera physalus) retain only the femur; the minke whale (Balaenoptera bonaerensis) retains the femur in about one-third of individuals; and the hindlimb is absent in the sei whale (Balaenoptera borealis)."³ Struthers found in the bowhead not just the bones but a knee: "The synovial capsule representing the knee-joint was too evident to be overlooked. An acetabular cartilage, synovial cavity, and head of femur, together represent the hip-joint."¹ In two of his whales the hip joint had fused solid "without trace of disease, showing that these movements may be dispensed with."¹

What attaches to them

In the male finless porpoise, Tajima and colleagues traced three muscles arising from the pelvic bone, the ischiocaudalis running back to the tail chevrons, the ischiocavernosus and the bulbospongiosus, and found "a pair of Crura penis, arising from the medio-ventral surface at almost middle of the pelvic bones with very strong attachments," uniting to form the body of the penis.¹¹ Their conclusion: "It is evident that the pelvic bones of the finless porpoise male act to support the penis in similar way as those of terrestrial mammals."¹¹ Dines and colleagues give the same picture for cetaceans generally: "the paired ischiocavernosus muscles insert deeply towards the distal end of the penis, while proximally encapsulating the paired crus of the penis which anchor to each pelvic bone," and these muscles "appear to maneuver the penis by pulling it to one side or the other."² In females, "ischiocavernosus muscles originate on the pelvic bone, but insert instead on the clitoris."²

The sexes differ, and they have since Struthers. "In the female the pelvic bone is shorter, more bent, broader at the angle, and, above all, thinner at and towards the hinder end, than in the male,"¹ and "the pelvic bone is much heavier in all the adult males than in any of the females."¹ Tajima and colleagues found the same in porpoises,¹¹ and Duras and colleagues could sex an adult bottlenose dolphin from its hip bone alone with 97 percent accuracy, the male bone being "significantly longer, heavier, and more robust" and carrying a larger tuberosity where the muscles attach.¹² Struthers saw the function in 1881 and then said what it does not explain: "The function point of view fails to account for the presence of a femur in addition to processes from the pelvic bone."¹

Which bone is it?

The primaries disagree, and creationists have noticed. Struthers argued from the soft tissue: "as there is no evidence that the pelvic bone is developed from more than one centre of ossification, these terms are apt to mislead," and the posterior part "attaches the crus penis, entitling us to regard the one pelvic bone as an ischium."¹ Tajima and colleagues read it as "a fused remnant of the Os pubis and the Os ischii, instead of Os ilium and Os ischii which was proposed by Abel."¹¹ Senter and Moch list three positions in the literature and settle on this: "Its connections with soft anatomy indicate that much of the girdle is the ischium," while the acetabulum still present in some baleen whales "suggests that all three bones are present, at least in reduced form."³ Duras and colleagues are blunter about what is missing: "we are unaware of specific developmental data for extant species documenting separate presumptive bones ... and/or establishing homology with the bony elements in terrestrial mammals."¹² The dispute is which parts of the hip survive, not whether it is a hip; Duras and colleagues themselves recommend calling it the hip bone because "the small bones in question are homologous not to the pelvis of terrestrial mammals but to their hip bones."¹²

Part 2: Dines 2014, and the claim it retired

What the paper did

Dines, Otárola-Castillo, Ralph, Alas, Daley, Smith and Dean laser-scanned pelvic bones from 130 adult museum specimens across 29 species, fitted 962 semi-landmarks to each, and compared size and shape after correcting for the family tree.² Their proxy for the intensity of sexual selection was relative testis mass, the standard measure of sperm competition. Their control was the first pair of ribs, another paired bone with nothing to do with mating. Two results: "males from species with relatively intense sexual selection (inferred by relative testes size) have evolved relatively large penises and pelvic bones compared to their body size," and "pelvic bone shape diverges more quickly in species pairs that have diverged in inferred mating system." Then the control: "Neither pattern was observed in the anterior-most pair of vertebral ribs, which served as a negative control."²

Female pelvic bone size also rose with the testis mass of their species' males, and the bones were sexually dimorphic in both size and shape, which the authors take to mean "pelvic bones function in unique aspects of male and female reproductive ecology."² They say what they do not know: "Because direct observations of cetacean mating behavior are scant, this hypothesis remains speculative."² The measured fact is the correlation with the control; the mechanism is a hypothesis.

What the paper said, both ways

The paper is cited by creationists for one sentence in its discussion: "Importantly, our study rejects a common assumption (mostly among non-cetacean biologists) that cetacean pelvic bones are 'useless vestiges' ... and instead suggest they are a critical component of male, and possibly female, reproductive fitness."² The assumption it rejects is sourced to one 1989 biology text, Curtis and Barnes. The same paper's abstract opens by saying that since evolving from land-dwelling ancestors, cetaceans "lost external hind limbs and evolved a highly reduced pelvis which seems to serve no other function except to anchor muscles that maneuver the penis,"² and its introduction says the pelvic girdle "evolved to a highly reduced state" over about 7 million years.² The closing line of the abstract ties the two together: "These important functions may explain why cetacean pelvic bones have not been lost through evolutionary time."² The authors' claim is that a reduced hip was kept and reshaped because it acquired a second job: Darwin's "retained for one alone of its former functions" with a control group.

The functionless claim died in 1990, not 2014

Creationist accounts present Dines 2014 as the moment evolutionists admitted function. The record is older. Struthers described the muscles and the crus penis in 1881. The functionless reading is Kellogg's, from 1936: Gingerich and colleagues report that the Basilosaurus pelvis and femur collected in the 1890s "were considered vestigial and functionless," citing Kellogg, "an interpretation consistent with loss of functional hind limbs in modern whales."⁴ Their own 1990 paper then argued the opposite for Basilosaurus, whose hind limbs "are interpreted as copulatory guides."⁴ Earlier still, Ernest Conrad wrote in Creation/Evolution in 1982, citing Yablokov's work on whale pelvic function, that creationists "gain very little by the 'advancing knowledge' that keeps discovering useful, but altered, functions for organs formerly defined as 'vestigial.' These organs still demonstrate descent with modification."¹³ Jerry Coyne's 2009 popular account, which Guliuzza quotes, does say the bones "became disconnected and tiny when they were no longer needed,"¹⁴ and Dines 2014 corrects that phrasing. But the primary literature had already moved, and the correction runs from Struthers to Gingerich to Dines with no creationist at any step.

Part 3: The embryo starts a leg and stops

Whale embryos begin hind limbs. Andrews knew it in 1921 from Kükenthal's humpback embryos: in a 32 mm embryo the hind-limb rudiments "are best developed and are 2 mm. long," and in later stages they shrink to "minute papillae."⁶ Sedmera, Míšek and Klima sectioned spotted dolphin embryos of 10 to 30 mm in 1997 and found that the buds "show histodifferentiation comparable with other mammals. Initially, they form the apical ectodermal ridge, which soon regresses," and that mesenchyme condenses into the beginnings of skeletal elements before the cells die or are absorbed into the body wall.¹⁵

Thewissen, Cohn and colleagues found the switch in 2006. In dolphin embryos "the bud arrests and degenerates around the fifth gestational week." The bud forms an apical ectodermal ridge that expresses Fgf8 at first, "but that neither the AER nor Fgf8 expression is maintained." The posterior signalling centre never forms: "Sonic hedgehog (Shh), which mediates the signaling activity of the ZPA, is absent from the dolphin hind-limb bud," and "failure to establish a ZPA is associated with the absence of Hand2, an upstream regulator of Shh."⁵ The forelimb bud of the same embryos expresses both genes normally, so the difference is local to the hind limb.⁵ Then the link to the adult bones: "Modern cetaceans have a strongly reduced hind-limb skeleton embedded in the ventral abdominal wall. It consists, at most, of innominate, femur, and tibia, and at least just the innominate (e.g., in Stenella). Interestingly, mice lacking Shh expression are strikingly similar to the cetacean pattern: Both exhibit loss of distal limb structures, but retain parts of the remaining limb skeleton embedded within the body wall."⁵

So the pelvic bone and the buried femur are what a mammalian limb program leaves behind when its distal signalling is cut, and the program still starts in every dolphin. What it does not show is a sudden macro-mutation. The authors say the fossils forbid that reading: "hind-limb size was reduced by gradually operating microevolutionary changes. Long after locomotor function was totally lost, modulation of developmental control genes eliminated most of the hind-limb skeleton. Hence, macroevolutionary changes in gene expression did not drive the initial reduction in hind-limb size."⁵ They also hedge the order of events: "we cannot exclude the possibility that the Hand2 domain was eliminated from the hind-limb bud after the leg had been reduced via other mechanisms."⁵ A creationist should notice that this is loss of expression, not gain, which is the kind of change every young-earth model already allows. A skeptic should notice that the bud forms at somite 43, which "indicates that the 39th vertebra is homologous to the first sacral vertebra of land mammals":⁵ the embryo marks where the hip used to join the spine.

Part 4: The rare whales with legs

A few whales are born with the program not stopped. Four cases have open primary descriptions and a fifth is known through a later note; Ohsumi lists further sperm whale records by Nemoto in 1963 and two more cases reviewed by Slijper,⁸ and Yablokov knew six sperm whale cases by 1974.¹³

The 1919 humpback. Roy Chapman Andrews reported in American Museum Novitates that "In July 1919, a female Humpback Whale (Megaptera nodosa) with two remarkable protrusions on the ventral side of the body, posteriorly, was captured by a ship operating from the whaling station at Kyuquot, on the west coast of Vancouver Island, British Columbia."⁶ Sidney Ruck of the Consolidated Whaling Company wrote that the whale had "elementary legs protruding from the body about 4 feet 2 inches, covered with blubber about one-half an inch thick."⁶ One limb was cut off and lost; the other was photographed in place and its bones sent to Andrews, who described "two bones and two heavy cartilages" totalling 31 inches, which he identified as a cartilaginous femur, a bony tibia, a cartilaginous tarsus and a bony metatarsal, in that order.⁶ His verdict: "I have come to the conclusion that the protrusions actually do represent vestigial hind limbs and show a remarkable reversion to the primitive quadripedal condition."⁶ His reasons: the limbs were symmetrical and "in the exact position in which the hind-limb rudiments have been found in embryonic Megaptera."⁶ He also gave the rarity: "Although hundreds of thousands of whales have been killed, especially in the last fifty years since the beginning of shore-whaling, no other instance has been reported."⁶

The 1956 sperm whale. Ogawa and Kamiya dissected the excised skin and blubber from a 10.6 m female landed at Ayukawa, Japan, with paired bumps beside the genital slit, 5.35 and 6.56 cm high.⁷ Inside the left one they found a pelvic bone of 19.5 cm, a cartilage-covered femur "taking the form of a small ball with the diameter ca. 3 cm," and a 13 cm partly ossified stick they provisionally called a tibia, with "no joint like the knee" between them.⁷ Their reading matched Andrews': the case "can be understood by assuming abnormal retention of the early embryonic state, and show very probably an atavism back to the quadripedal condition of the whales' remote ancestors. It can never be a malformation of no phylogenetic significance."⁷

The 1963 dolphin. Ohsumi found, among 450 striped dolphins caught at Kawana, a mature 230 cm male with a pair of ellipsoid bumps on either side of the mammary slit, 28 and 33 mm long and 10 and 13 mm high.⁸ He gave the denominator: "Dr. Nishiwaki and his group have investigated this species of dolphin on about ten thousand individuals, but it is the first time for us to find such an individual."⁸

The Taiji dolphins. In 2006 a bottlenose dolphin with a symmetrical pair of fin-shaped hind appendages was taken off Taiji and described by Ohsumi and Kato in Marine Mammal Science in 2008, a paper this project could not open.¹⁶ In January 2023 the Taiji Whale Museum found a second, a 182 cm male striped dolphin whose appendages were 4.3 and 5.8 cm long and "similar to that of the pectoral flippers but more sticklike."¹⁶ No skeletal description has yet been published for either.

What the two sides make of them

Dines and colleagues mention the cases only to set them aside: "in extremely rare cases individuals develop external hindlimbs," but "these additional bones do not attach to the ischiocavernosus muscles and are ignored here."² Senter and Moch count them as the exception that proves loss is not quite irreversible.³ The evolutionary reading, from Andrews to Ogawa, is that a program still present in every embryo occasionally runs further than usual and builds a leg in tetrapod order because that is what it is.

The creationist reading is that these are developmental defects. Carl Wieland, in Creation in 1998, argued that "A mutational defect in this program could easily cause one or more extra pieces of bone to form, which would almost inevitably be in the same region," and compared them to extra fingers and ribs in people.¹⁷ He then set the test his own model must pass: "such an explanation would be unable to cope with the occurrence in modern whales of an actual leg (internal or external), since this would clearly have design features which would never have been needed if the first whales were created."¹⁷ His article discusses only Slijper's account of two sperm whales, calling it "purely anecdotal"; Slijper's 1956 Ayukawa whale is the animal Ogawa and Kamiya dissected and published with measurements the next year.¹⁷ It does not mention Andrews' 1921 humpback, which is the case with a femur, tibia, tarsus and metatarsal in series and has been in print, in the public domain, since June 1921. Bergman in 2012 takes the same line, "abnormal development caused by mutations or teratogens. Evidence for this includes their rarity in many whale species."⁹ Surtees wrote in the Journal of Creation in 2024 that "these historical accounts of atavistic legs have not been verified and there are no recent reports,"¹⁸ which is wrong on both counts: the 1957 report is a dissection and the 1965 report a measured description, and the second Taiji dolphin was published ten months before his paper.

The honest weighing: extra fingers copy a structure the animal already builds, while a femur, tibia and metatarsal in order copy nothing a whale builds, so the teratology reading must say where the pattern came from. Against that, a dozen or so cases in a century of whaling is a tiny sample, two are bumps with no published skeleton, and Ogawa's "tibia" is a stick with no knee. Neither side should lean on these alone.

Part 5: Does it pass the vestige test?

The parent article's live definition has three steps: homology with a fuller structure elsewhere, reduction, and a distribution that fits a tree built from other characters. Senter and Moch's criteria are the same test made operational: extreme reduction against the sister group, loss of the specialised form, and loss of a salient ancestral function, which a girdle meets "if it is not connected to the vertebral column."³ They apply it: "The pelvic girdle is vestigial in Cetacea (whales). It is extremely reduced in size, has lost contact with the vertebral column, and has lost a distinct acetabulum."³ Their definition says in advance that function is not the issue: "The term 'vestigial' does not imply a complete lack of any function," and whale pelves "have lost their ancestral locomotor function but still anchor muscles associated with the reproductive system."³

Step 1, homology, is the one a creationist can contest, and the primaries give some room: which of the three hip bones survives is unsettled, and Duras and colleagues concede there are no developmental data establishing the homology.¹² But the argument for a hip does not rest on shape. It rests on the crus penis and the ischiocavernosus attaching to it as they attach to the ischium of every mammal,¹ on the femur and tibia that hang from it in bowheads with a knee capsule and a hip cartilage,¹ on the embryo bud that forms at the sacral somite with the limb's own genes,⁵ and on the Basilosaurus innominate, "a straplike coossification of an elongated pubis and a relatively small ilium and ischium, each contributing to a well-defined acetabulum."⁴ Step 2, reduction, is conceded by every source on both sides, including the creationist ones that call the bones "small" and "strips." Step 3 is the fossil series, which this site's whale evolution article treats in full: a weight-bearing pelvis in Ambulocetus, a detached one in Georgiacetus and Basilosaurus, and the internal remnant of living whales.

A creationist must say one of two things instead. Either the bones are not a hip at all, which is Surtees' and Guliuzza's position and requires an account of the crus, the femur, the knee and the embryo; or they are a hip, reduced within the whale kind from a created whale that had a larger one, which is Wise's position and requires an account of why a created whale carried the information for a leg. Finding that the bones anchor the penis does neither.

Part 6: The creationist literature, in its own words

The oldest line is the function reply. Sarfati and Batten's 2006 Creation Answers Book entry reads in full: "These bones are alleged to show that whales evolved from land animals. However, Bergman and Howe point out that they are different in the male and female whales. They are not useless at all, but help penis erection in the males and vaginal contraction in the females."¹⁹ Wieland in 1998: "these strips of bone have a known function, differ in males and females, and are not even attached to the vertebral column."¹⁷ Bergman in 2012: "Their support role fits either the design, or the descent-with-modification view, but either way they are not vestigial. Creationists also once effectively explained the whale hip bones as evidence of degeneration, but this view is no longer valid because a clear function has now been determined for the bones."⁹ Brian Thomas at ICR on Dines 2014: "These results show that male whales use pelvis bones that were well crafted for anchoring reproductive organs—not for anchoring limbs. Whale hips are not vestigial."²⁰ Answers in Genesis' vestigial-structures page: "Even though it has a clear reproductive function, evolutionists call it a left-over from a time when whales walked on land."²¹ Patricia Engler on the same site: "Even pelvic bones in whales serve essential reproductive functions."²² All of these are true, and all of them answer Kellogg's 1936 claim. Against the modern definition, the reply "it has a function" concedes the case: a functional vestige is still a vestige, and Bergman's own sentence admits the bones fit descent with modification.

Two moves go further. Randy Guliuzza at ICR denies the homology outright: "The assertion that these bones are hip bones or a pelvis is a mystical claim," and "Co-option is not an observation, it is a declaration."²³ Marc Surtees in 2024 makes the same denial with criteria: homology needs the same fundamental structure, the same relations and the same development, and the bones "are located within the body wall of the abdomen or the reproductive organs, which disqualifies them from being vestigial legs."¹⁸ This is the right argument, and the first creationist treatment found that engages homology rather than function. Its weakness is that it stops at the rod. The ischium of a land mammal is also where the crus penis attaches; the bowhead's femur and knee capsule, the dolphin's Hand2-less limb bud at the sacral somite, and Andrews' femur-tibia-tarsus-metatarsal series are the "same development" and "same relations" evidence, and neither author discusses them.

The other move is concession. Kurt Wise, in 1995, called the whales "the largest challenge from the stratomorphic intermediate record"¹⁰ and offered as one escape that "modern cetaceans have latent genetic information for the development of small hind limbs," so that Basilosaurus might be "an early post-Flood representative of some cetacean baramin."¹⁰ Wieland, answering the 2006 Taiji dolphin, said the same of fins: "Today's two-finned dolphins may actually have the latent genetic information for generating all four fins. All dolphins may have once had two rear fins, and subsequently lost the information for generating them."²⁴ Sarfati and Batten's general rule covers it: "even if the alleged vestigial organ were no longer needed, it would prove devolution not evolution."¹⁹ This reply fits the evidence, and it costs something: it grants a created whale kind whose members once had larger hips and hind appendages, and moves the argument to where the kind boundary sits, which is the whale evolution article's question.

Engler adds that vestige arguments "must assume evolution is true in order to claim that evolution is true."²² The charge runs in reverse too: latent information and lost fins are creationist readings of the same bones. Neither side reads the pelvis without a prior on ancestry, and the femur, the embryo and the fossils decide between the priors, not the pelvis alone. The old-earth creationist Fazale Rana states the mainstream reply fairly: evolutionists "will maintain that the whale pelvis is a homologous structure, even if it isn't vestigial, and therefore supports common ancestry."²⁵

Objections and responses

Creationist: "Dines 2014 proved the bones are not vestigial." Dines and colleagues rejected the label "useless vestiges" and in the same paper called the pelvis "highly reduced" and its retention a consequence of function.² They found a functional vestige, which is what the modern definition predicts.

Creationist: "Nobody knows which hip bone it is, so it is not a hip." The uncertainty is about which parts survive, not about what the bone is.³ A rod with the crus penis on it, a femur hanging from it in bowheads, and an embryonic limb bud above it is a hip in every sense that matters.

Creationist: "The atavisms are birth defects." Possibly, for the bumps. Not obviously for a femur, tibia, tarsus and metatarsal in tetrapod order, and Wieland's own test says an actual leg would be a problem for the created-whale reading.¹⁷ A dozen cases in a century is too few for either side to lean on.

Creationist: "The hind-limb genes were simply switched off, which is loss, not gain." Correct, and Thewissen and colleagues say the same: the developmental change followed the reduction and did not drive it.⁵ Loss within a kind is the honest creationist reading. It concedes a created whale with a larger hip.

Skeptic: "The function is beside the point; the bone is a leftover." The function explains why the bone was retained and why it is sexually dimorphic. Anyone still teaching that the bones do nothing is teaching something Struthers' dissections contradicted in 1881 and Dines measured in 2014.

Skeptic: "Creationists just deny homology when it is inconvenient." Surtees' criteria are the ones comparative anatomists use, and Duras and colleagues concede that developmental data on the bone's origin do not exist. Homology is not obvious from the rod; it is carried by the soft tissue, the femur, the embryo and the fossils, which the creationist treatments do not address.

Skeptic: "This article accepts every observation and still refuses the conclusion." It refuses one conclusion: that the pelvis by itself settles ancestry. The bones are reduced, homologous with a hip, retained for a second job, and built by a limb program that still starts in every embryo. What that shows depends on whether the fuller hip sits inside or outside the whale kind, and no creationist source has said where that boundary falls.

Issues and unanswered questions

Ohsumi and Kato 2008, the primary description of the 2006 Taiji dolphin, could not be opened; the case is held through Inamori and colleagues 2023. No skeletal study of either Taiji animal has been published.
No developmental study has followed the ossification of the cetacean pelvic bone itself, so the ischium-pubis-ilium question stays open.¹²
Dines and colleagues' mechanism, penis control against female avoidance, rests on scant behavioural observation and is marked speculative by its authors.
No creationist source states what a created whale's pelvis and hind limb looked like, or prices how much reduction a post-Flood whale kind must have undergone in how many generations.
Kükenthal 1914 and Yablokov 1974 are held only through Andrews and Conrad.

Verdict

The whale pelvis is both things the two sides say it is. It anchors the crura and the ischiocavernosus muscles, differs between the sexes, and grows with the intensity of sexual selection across 29 species while the ribs do not. It is also a pair of detached rods with no socket and no joint to the spine, at two to four percent of body length, from which a femur and sometimes a tibia still hang in baleen whales, above a limb bud that every dolphin embryo starts and stops for want of Hand2 and Shh. The creationist literature has answered the claim that the bones are useless, rightly. It has not answered the claim that they are reduced homologues, because that claim is carried by the femur, the embryo and the fossils, and the two creationist authors who engage homology stop at the rod. The position that fits the evidence is Wise's: the information for a hind limb is still in the genome of every whale, and the young-earth account owes an explanation of why.

Sources

1.
Struthers, John. “The bones, articulations, and muscles of the rudimentary hind-limb of the Greenland right-whale (Balaena mysticetus).” Journal of Anatomy and Physiology 15(2):141–176. 1881. A dissection study by John Struthers, professor of anatomy at Aberdeen, of the muscles, ligaments and joints around the hind-limb rudiments of ten Greenland right whales taken in Davis Straits, dissected between 1873 and 1876. He found a knee-joint and a hip-joint, and he argued that the names for the three parts of the pelvic bone mislead, because the bone has only one centre of ossification. The article uses him for the view that the rudiments look useless, for his finding that they are femur and tibia, and for his measurements of the bone in the two sexes.
1. 1a.
  Page 142: “Nothing can be imagined more useless to the animal than rudiments of hind legs entirely buried beneath the skin of a whale, so that one is inclined to suspect that these structures must admit of some other interpretation. Yet, approaching the inquiry with the most skeptical determination, one cannot help being convinced, as the dissection goes on, that these rudiments really are femur and tibia.” ↩
2. 1b.
  Page 142: “The synovial capsule representing the knee-joint was too evident to be overlooked. An acetabular cartilage, synovial cavity, and head of femur, together represent the hip-joint.” “in two of these whales the hip-joint was firmly anchylosed, in one of them on one side, in the other on both sides, without trace of disease, showing that these movements may be dispensed with.” ↩ ↩ ↩
3. 1c.
  Page 143: “The function point of view fails to account for the presence of a femur in addition to processes from the pelvic bone.” ↩
4. 1d.
  Page 148: “as there is no evidence that the pelvic bone is developed from more than one centre of ossification, these terms are apt to mislead”. “The posterior part, besides attaching muscles and ligaments, attaches the crus penis, entitling us to regard the one pelvic bone as an ischium.” ↩ ↩
5. 1e.
  Page 149: “In the female the pelvic bone is shorter, more bent, broader at the angle, and, above all, thinner at and towards the hinder end, than in the male.” ↩
6. 1f.
  Page 150: “In the 62 feet long female (No. IV.), with an angle of 135°, the length is about 15 inches, while in the 48 feet long male (No VII.) with an angle of 143°, the length is almost 20 inches.” ↩ ↩
7. 1g.
  Page 150: “the pelvic bone is much heavier in all the adult males than in any of the females.” ↩
2.
Dines, James P. et al. “Sexual selection targets cetacean pelvic bones.” Evolution 68(11):3296–3306. 2014. A comparative study of pelvic bones from 130 individuals of 29 cetacean species, which measured each bone's size and shape and set them against the mating system inferred for each species, with the first pair of ribs as a control. It found that males of species with relatively intense sexual selection, judged by relative testes size, have relatively large penises and pelvic bones for their body size, and that pelvic bone shape diverges faster in species pairs whose mating systems differ; the ribs showed neither pattern. The authors call one of their hypotheses speculative because direct observations of cetacean mating are scant, but the article uses the study as evidence that the bones are not mere relics and that their function can be measured.
1. 2a.
  Section Introduction: The closing sentence of the introduction. “Our study suggests that far from being mere relics of a terrestrial past, cetacean pelvic bones are targets of sexual selection.” ↩
2. 2b.
  Section Abstract: “since evolving from land-dwelling ancestors, they lost external hind limbs and evolved a highly reduced pelvis which seems to serve no other function except to anchor muscles that maneuver the penis.” ↩ ↩ ↩
3. 2c.
  Section Abstract: “1) males from species with relatively intense sexual selection (inferred by relative testes size) have evolved relatively large penises and pelvic bones compared to their body size, and 2) pelvic bone shape diverges more quickly in species pairs that have diverged in inferred mating system. Neither pattern was observed in the anterior-most pair of vertebral ribs, which served as a negative control.” ↩ ↩
4. 2d.
  Section Abstract: The abstract's closing sentence. “These important functions may explain why cetacean pelvic bones have not been lost through evolutionary time.” ↩
5. 2e.
  Section Introduction: “the cetacean pelvic girdle evolved to a highly reduced state (Fig. 1A) over the span of roughly 7 million years”. ↩
6. 2f.
  Section Introduction: “Cetacean pelves no longer share a symphysis at the sacrum, no longer contact the vertebral column, have lost their acetabulum and obturator foramen, and evolved to such small size that there is still no general consensus as to which of the three fused bones found in their terrestrial ancestor (ischium, ilium and/or pubis) they derive from”. ↩
7. 2g.
  Figure 1: In the caption. “An adult male of approximately 3 meters”. “These pelvic bones are approximately 11 cm long.” ↩ ↩
8. 2h.
  Section Introduction: “all 92 extant cetacean species except two (Kogia sima and K. breviceps, which appear to have replaced their pelvic bones with functional cartilaginous sheets, Benham 1901) have retained their pelvic bones.” ↩ ↩
9. 2i.
  Section Introduction: “In male cetaceans, the paired ischiocavernosus muscles insert deeply towards the distal end of the penis, while proximally encapsulating the paired crus of the penis which anchor to each pelvic bone”. “The ischiocavernosus muscles appear to maneuver the penis by pulling it to one side or the other.” ↩ ↩
10. 2j.
  Section Methods: “As in males, female ischiocavernosus muscles originate on the pelvic bone, but insert instead on the clitoris.” ↩
11. 2k.
  Section Introduction and methods: 130 adult specimens from 29 species, 962 semi-landmarks per bone, phylogenetic generalised least squares and a Bayesian model of correlated evolution. ↩
12. 2l.
  Section Results: “Taken together, these results suggest that pelvic bones function in unique aspects of male and female reproductive ecology.” ↩
13. 2m.
  Section Discussion: “Because direct observations of cetacean mating behavior are scant, this hypothesis remains speculative.” ↩
14. 2n.
  Section Discussion: “Importantly, our study rejects a common assumption (mostly among non-cetacean biologists) that cetacean pelvic bones are 'useless vestiges' (Curtis and Barnes 1989), and instead suggest they are a critical component of male, and possibly female, reproductive fitness.” ↩ ↩
15. 2o.
  Section Methods: “some cetacean species retain internal vestiges of femurs and/or tibiae (Struthers 1881; Howell 1970; Omura 1980) and in extremely rare cases individuals develop external hindlimbs (Andrews 1921; Sleptsov 1939; Ohsumi 1965; Berzin 1972). However, these additional bones do not attach to the ischiocavernosus muscles and are ignored here.” ↩
3.
Senter, Phil, and John G. Moch. “A critical survey of vestigial structures in the postcranial skeletons of extant mammals.” PeerJ 3:e1439. 2015. A descriptive survey of vestigial skeletal structures, which are parts that have lost their ancestral function and are usually much reduced, across the skeletons of living mammals. The authors examined 578 skeletal specimens and skins from 293 species, about 70 percent of the 139 living mammal families, and supplemented their own observations with earlier published descriptions as needed. The article uses it for which baleen whales keep a hind bone, for the three readings of the whale pelvis, and for the claim that a vestigial structure can keep some function. Mirror: PMC
1. 3a.
  Section Hindlimb: “Typically, the bowhead whale (Balaena mysticetus) retains the femur and tibia; the humpback (Megaptera novaeangliae) and fin whale (Balaenoptera physalus) retain only the femur; the minke whale (Balaenoptera bonaerensis) retains the femur in about one-third of individuals; and the hindlimb is absent in the sei whale (Balaenoptera borealis)”. ↩ ↩
2. 3b.
  Section Pelvic girdle: “Previous authors have disagreed as to whether the cetacean pelvic girdle retains the ischium alone (Struthers, 1881; Simões-Lopes & Gutstein, 2004), the ischium and ilium (Abel, 1908; Lönneberg, 1910; Schulte, 1916; Howell, 1930), or the ischium, ilium, and pubis (Gol'din, 2014). Its connections with soft anatomy indicate that much of the girdle is the ischium”. “the presence of the acetabulum in mysticetes (Struthers, 1881; Fordyce et al., 2000; Gol'din, 2014) suggests that all three bones are present, at least in reduced form”. ↩ ↩
3. 3c.
  Section Methods: “The first criterion for vestigiality is that in comparison to its state in the sister groups the structure exhibits extreme reduction”. “The second criterion is that the structure has lost the specialized morphology that it exhibits in the sister groups”. “The third criterion is that the structure has lost a salient ancestral function”. “A pelvic girdle further satisfies this criterion if it is not connected to the vertebral column”. ↩
4. 3d.
  Section Pelvic girdle: “The pelvic girdle is vestigial in Cetacea (whales). It is extremely reduced in size, has lost contact with the vertebral column, and has lost a distinct acetabulum”. ↩
5. 3e.
  Section Introduction: “The term 'vestigial' does not imply a complete lack of any function”. “vestigial whale pelves have lost their ancestral locomotor function but still anchor muscles associated with the reproductive system (Struthers, 1881; Simões-Lopes & Gutstein, 2004).” ↩
6. 3f.
  Section Methods: “atavistic limbs in aberrant cetacean and sirenian individuals show that loss is not completely irreversible (Abel, 1908; Andrews, 1929; Ogawa & Kamiya, 1957; Ohsumi, 1965).” Their "Andrews, 1929" is the 1921 Novitates paper. ↩
4.
Gingerich, P. D. et al. “Hind limbs of Eocene Basilosaurus: evidence of feet in whales.” Science 249:154–157. 1990. A 1990 research paper in Science describing the hind limbs of Basilosaurus, a fossil whale from the Eocene epoch. Its authors read those limbs as copulatory guides, structures that steer the penis during mating, and not as the functionless remnants that earlier writers had assumed. The article uses it for the 1990 view that the Basilosaurus limbs were functional, and for the authors' description of living whales as keeping only rod-like vestiges of the hind limbs. Mirror: Archive.org
1. 4a.
  Page 154: “Modern cetaceans live in water and lack hind limbs entirely, retaining only rod-like vestiges of pelvic bones, femora, and rarely tibiae embedded in musculature of the ventral body wall”. ↩
2. 4b.
  Page 154: Of the B. cetoides pelvis and femur collected in 1894–1896: “these remains were considered vestigial and functionless (14), an interpretation consistent with loss of functional hind limbs in modern whales.” Reference 14 is Kellogg 1936. ↩ ↩
3. 4c.
  Page 154, section Abstract: “Hind limbs of Basilosaurus are interpreted as copulatory guides.” ↩
4. 4d.
  Page 154: “The innominate (Fig. 1B) is a straplike coossification of an elongated pubis and a relatively small ilium and ischium, each contributing to a well-defined acetabulum. The pubis and ischium surround a small obturator foramen.” ↩
5.
Thewissen, J. G. M. et al. “Developmental basis for hind-limb loss in dolphins and origin of the cetacean bodyplan.” PNAS 103(22):8414–8418. 2006. A laboratory study of gene activity in the hind-limb buds of pantropical spotted dolphin embryos (Stenella attenuata). It found that the hind-limb bud forms a signalling ridge at first, but the posterior signalling centre, a patch of cells that sends chemical instructions to the limb, never forms, so the leg stops developing. The article uses it for the evidence that a dolphin's leg starts and then stops, and for the authors' view that the leg shrank gradually. Mirror: PMC
1. 5a.
  Section Abstract: “cetacean embryos do initiate hind-limb bud development. In dolphins, the bud arrests and degenerates around the fifth gestational week”. “the cetacean hind-limb bud forms an AER and that this structure expresses Fgf8 initially, but that neither the AER nor Fgf8 expression is maintained. Moreover, Sonic hedgehog (Shh), which mediates the signaling activity of the ZPA, is absent from the dolphin hind-limb bud. We find that failure to establish a ZPA is associated with the absence of Hand2, an upstream regulator of Shh.” ↩ ↩
2. 5b.
  Section Results: “Although Shh was expressed posteriorly in the fore limb of Stenella embryos during Carnegie 14 and 15 (Fig. 2 G and H), it was not detected in the posterior hind-limb bud mesenchyme of the same embryos”. “Hand2 expression in the fore-limb region at Carnegie 12 follows the generalized pattern (Fig. 2A), but Hand2 was undetectable in the area of the developing hind limb”. ↩
3. 5c.
  Section Discussion: “Modern cetaceans have a strongly reduced hind-limb skeleton embedded in the ventral abdominal wall (Fig. 3). It consists, at most, of innominate, femur, and tibia (25), and at least just the innominate (e.g., in Stenella). Interestingly, mice lacking Shh expression are strikingly similar to the cetacean pattern: Both exhibit loss of distal limb structures, but retain parts of the remaining limb skeleton embedded within the body wall (26).” ↩ ↩
4. 5d.
  Section Abstract: “Integration of paleontological and developmental data suggests that hind-limb size was reduced by gradually operating microevolutionary changes. Long after locomotor function was totally lost, modulation of developmental control genes eliminated most of the hind-limb skeleton. Hence, macroevolutionary changes in gene expression did not drive the initial reduction in hind-limb size.” ↩ ↩
5. 5e.
  Section Discussion: “we cannot exclude the possibility that the Hand2 domain was eliminated from the hind-limb bud after the leg had been reduced via other mechanisms, which would have relaxed the selective pressure to maintain an active signaling pathway in the hind-limb bud.” ↩
6. 5f.
  Section Discussion: “The hind-limb bud is located near Somite 43 at Carnegie Stage 13, indicating that the 39th vertebra is homologous to the first sacral vertebra of land mammals”. ↩ ↩
6.
Andrews, Roy Chapman. “A remarkable case of external hind limbs in a humpback whale.” American Museum Novitates 9:1–6. Jun 3, 1921. A six-page museum paper on a humpback whale captured off Vancouver Island in July 1919 that had two external protrusions. It rests on a photograph of one protrusion in place, its bones sent to the author, and a letter from an officer of the whaling company. The article uses it for the 1919 humpback and for Andrews' conclusion that the protrusions were vestigial hind limbs showing a reversion to the primitive four-legged condition.
1. 6a.
  Page 1: “In July 1919, a female Humpback Whale (Megaptera nodosa) with two remarkable protrusions on the ventral side of the body, posteriorly, was captured by a ship operating from the whaling station at Kyuquot, on the west coast of Vancouver Island, British Columbia.” ↩
2. 6b.
  Page 2: Sidney Ruck's letter of 4 March 1920: “This particular whale was a female humpback of the average length with elementary legs protruding from the body about 4 feet 2 inches, covered with blubber about one-half an inch thick.” Ruck's words, not Andrews'; the paper gives no length for the whale. ↩
3. 6c.
  Page 2: “I have come to the conclusion that the protrusions actually do represent vestigial hind limbs and show a remarkable reversion to the primitive quadripedal condition.” Original spelling of "quadripedal". “the tendency will be to consider this a teratological case of no reversionary significance, but the evidence is so strong that I can not interpret it in that way.” ↩ ↩
4. 6d.
  Page 2: “The skeletal remains in my possession consist of two bones and two heavy cartilages. When placed in position as in Fig. 2, the total length is 31 inches.” Page 4: Identifies them under the headings FEMUR (cartilage), TIBIA (bone), TARSUS (cartilage) and METATARSAL (bone). ↩
5. 6e.
  Page 4: “The pelvic bones, as usually present in the Megaptera, are slender ossifications about 6 or 8 inches in length”. ↩
6. 6f.
  Page 5: Summarising Kükenthal's 1914 humpback embryos. “In Kukenthal's Stage I (an embryo 32 mm. in length) the rudiments are best developed and are 2 mm. long”. In Stage III, “the hind-limb rudiments have still more decreased in size and appear as minute papillae.” ↩
7. 6g.
  Page 6: “The limbs, according to the statements of the whalers, were symmetrical; they are in the exact position in which the hind-limb rudiments have been found in embryonic Megaptera”. ↩
8. 6h.
  Page 6: “Although hundreds of thousands of whales have been killed, especially in the last fifty years since the beginning of shore-whaling, no other instance has been reported.” ↩
7.
Ogawa, Teizo, and Toshiro Kamiya. “A case of the cachalot with protruded rudimentary hind limbs.” Scientific Reports of the Whales Research Institute 12:197–208. 1957. A case report by two anatomists at the University of Tokyo on a 10.6 m female cachalot (sperm whale) with a pair of small protrusions beside its genital opening. They examined excised skin and blubber from the protrusions and found a pelvic bone, a cartilage-covered femur and a partly ossified 13 cm stick that they called a tibia. The article uses it for the 1956 sperm whale and for the authors' reading, like Andrews', that the protrusions are an atavism, a return to a feature of an ancestor.
1. 7a.
  Page 198: “it was a female measuring 10.6 m in length. The protuberances were present on both sides of the genital opening”. “The height measures 5.35 cm on the right side, 6.56 cm on the left.” ↩
2. 7b.
  Pages 198–199: “The pelvic bone measuring 19.5 cm in length was found there”. Page 200: “the femur covered with cartilage is present taking the form of a small ball with the diameter ca. 3 cm”. “a mostly cartilaginous stick of the length 13 cm is present. It is only partially ossified”. “Between femur and tibia no joint like the knee exists, as both bones are not in contact but far (4.8 cm) apart from each other.” ↩
3. 7c.
  Page 207: “This case can be understood by assuming abnormal retention of the early embryonic state, and show very probably an atavism back to the quadripedal condition of the whales' remote ancestors. It can never be a malformation of no phylogenetic significance.” ↩ ↩
8.
Ohsumi, Seiji. “A dolphin (Stenella caeruleoalba) with protruded rudimentary hind limbs.” Scientific Reports of the Whales Research Institute 19:135–136. 1965. A short report of one dolphin of the species Stenella caeruleoalba with a pair of protruding, rudimentary hind limbs. The male was 230 cm long, and its two protrusions were 28 and 33 mm long and 10 and 13 mm high. The article uses it for the 1963 dolphin and for the rarity figure of about one in ten thousand, which rests on the number of dolphins Nishiwaki's group had investigated.
1. 8a.
  Page 135: “Present individual is a male, and is 230 cm long”. “The minor axis of the left and right limbs is 22 and 23 mm respectively, and the major axis of the left and right limbs is 28 and 33 mm respectively. The height is 10 and 13 mm in the left and right limbs respectively.” ↩
2. 8b.
  Page 135: “Dr. Nishiwaki and his group have investigated this species of dolphin on about ten thousand individuals, but it is the first time for us to find such an individual.” ↩ ↩
3. 8c.
  Page 135: “there have been reported for one humpback whale (Megaptera novaeangliae; Andrews, 1921) and sperm whales (Physeter catodon; Ogawa & Kamiya, 1957; Nemoto, 1963). Slijper (1958) reviewed two similar records on a dolphin and a pilot whale.” ↩
9.
Bergman, Jerry. “Whale evolution: a whale of a tale.” Creation Research Society Quarterly 49(2):122–134. 2012. A journal article by Jerry Bergman in the Fall 2012 issue of the Creation Research Society Quarterly. It surveys the whale fossil record and argues that none of the proposed fossils is a viable transitional form. The article uses it for the argument that the whale pelvic bones have a function and are therefore not vestigial.
1. 9a.
  Page 129: “Their support role fits either the design, or the descent-with-modification view, but either way they are not vestigial. Creationists also once effectively explained the whale hip bones as evidence of degeneration, but this view is no longer valid because a clear function has now been determined for the bones.” Page 128: “The evolutionary explanation for the whale pelvic bones is that they are the useless vestigial remains of the pelvic girdle and the hind legs that existed when the whale ancestor was a terrestrial tetrapod”. ↩ ↩
2. 9b.
  Page 130: “One explanation for these whale 'leg' bones (and similar abnormalities) is they are due to abnormal development caused by mutations or teratogens. Evidence for this includes their rarity in many whale species.” A teratogen is an agent that causes birth defects. ↩
10.
Wise, Kurt P. “Towards a Creationist Understanding of 'Transitional Forms'.” CEN Technical Journal 9(2):216–222. 1995. A 1995 essay by the creationist palaeontologist Kurt Wise. It argues that creationists should not divert scarce resources into the transitional-forms debate, and it calls the fossil record of whales the largest challenge from the stratomorphic intermediate record. The article uses it for the escapes Wise offers from that challenge.
1. 10a.
  Page 220: “This suggests that modern cetaceans have latent genetic information for the development of small hind limbs. Could this mean that Basilosaurus, for example, (which has hind limbs and pelvis) is actually an early post-Flood representative of some cetacean baramin”. This is escape (b) of the four that Wise offers after calling the whale record 'the largest challenge' to creation theory, and the whale evolution article on this site prints all four. ↩ ↩
2. 10b.
  Page 219: “the largest challenge from the stratomorphic intermediate record appears to this author to come from the fossil record of the whales”. ↩
11.
Tajima, Yuko et al. “Comparative anatomical study on the relationships between the vestigial pelvic bones and the surrounding structures of finless porpoises (Neophocaena phocaenoides).” Journal of Veterinary Medical Science 66(7):761–766. 2004. A dissection study of three finless porpoises, a small toothed whale, that traces the pelvic bones and the muscles and tissues around them. It found that the bones are slender rods with no joint to the spine, and that in the male they support the penis as the pelvic bones of land mammals do. The article uses it for the shape of these bones in both sexes, for the muscles that attach to them in males, and for its view that the male bones hold the penis.
1. 11a.
  Page 761: In the abstract. “a pair of slender rod-like structures within the abdominal wall muscles just anterior to the anus with no articulations to the axial skeleton”. ↩
2. 11b.
  Page 762: “The pelvic bones in male specimens were more elongated, robust and larger than those of a female.” ↩
3. 11c.
  Page 762: “a pair of Crura penis, arising from the medio-ventral surface at almost middle of the pelvic bones with very strong attachments, united to form the Corpus cavernosus penis”. The three muscles are named in the Fig. 3 caption, p. 763. ↩
4. 11d.
  Page 764: “It is evident that the pelvic bones of the finless porpoise male act to support the penis in similar way as those of terrestrial mammals.” ↩
5. 11e.
  Page 764: “the bone could be a fused remnant of the Os pubis and the Os ischii, instead of Os ilium and Os ischii which was proposed by Abel.” ↩
12.
Duras, Martina et al. “Hip bone morphometrics of bottlenose dolphins (Tursiops truncatus) from Adriatic Sea: sex determination and postnatal development.” Marine Mammal Science 32(3):945–959. 2016. A morphometric study of the hip bone (os coxae) of 131 bottlenose dolphins, 61 females and 70 males, salvaged from Croatian waters of the eastern Adriatic Sea and ranging in age from newborns to 28 years. It found that adult males' hip bones are longer, heavier and more robust than females', and that sex can be told from the bone with 97 percent accuracy; it also found a single ossification in each bone, yet argues that soft tissue and comparison with land mammals suggest the bone equals the three-part hip bone of land mammals, while admitting that it knows of no developmental data establishing that homology. The article uses it for the sex difference in the bone and for that admission that homology is not established by development. Mirror: Wwwi.vef.hr
1. 12a.
  Page 945: In the abstract. “fully-formed hip bones from males were significantly longer, heavier, and more robust than those from females”. “classification functions for reliable sex determination (97%)”. ↩
2. 12b.
  Pages 946–947: “we are unaware of specific developmental data for extant species documenting separate presumptive bones (likewise noted by Gol'din, 2014) and/or establishing homology with the bony elements in terrestrial mammals.” ↩ ↩ ↩
3. 12c.
  Page 947: “the small bones in question are homologous not to the pelvis of terrestrial mammals but to their hip bones.” ↩
13.
Conrad, Ernest C. “True Vestigial Structures in Whales and Dolphins.” Creation/Evolution (10):8–13. 1982. A Fall 1982 article by Ernest C. Conrad in the journal Creation/Evolution. It accepts that many organs once called vestigial have uses, and it draws on the Russian zoologist Alexy Yablokov's book Variability of Mammals, which accepts vestigial hind limbs in cetaceans and knows six cases in sperm whales alone. The article cites it for those six sperm whale cases.
1. 13a.
  Page 9: “This means that creationists gain very little by the 'advancing knowledge' that keeps discovering useful, but altered, functions for organs formerly defined as 'vestigial.' These organs still demonstrate descent with modification.” Bergman 2012 cites the same passage as Conrad 1983, p. 9. ↩
2. 13b.
  Page 10: Conrad is describing Yablokov's vestigial hind limbs. “He is aware of six cases in sperm whales alone.” ↩
14.
Coyne, Jerry A. Why Evolution Is True. Viking. 2009. A 2009 book by Jerry A. Coyne. The article quotes it for the account that the whale hip bones were once part of the skeleton and became disconnected and tiny when they were no longer needed.
1. 14a.
  Page 60: “They once were part of the skeleton, but became disconnected and tiny when they were no longer needed.” ↩
15.
Sedmera, David et al. “On the development of cetacean extremities: I. Hind limb rudimentation in the spotted dolphin (Stenella attenuata).” European Journal of Morphology 35(1):25–30. 1997. A laboratory study of spotted dolphin embryos 10 to 30 mm long, whose hind-limb buds were examined under the microscope at the level of tissues and cells. It found that the buds show the early steps of a mammal limb, including a ridge of cells that soon regresses and cell clusters that will form skeletal parts, and that some cells die while others are taken into the body wall. The authors call the temporary buds an example of recapitulation of phylogenesis in ontogenesis, meaning that the embryo briefly repeats its ancestors' development. The article uses it for the claim that dolphin embryos start hind limbs before those limbs disappear.
1. 15a.
  Section Abstract: “Hind limb buds of dolphin embryos, CRL 10-30 mm, were examined histologically. Before total disappearance, they show histodifferentiation comparable with other mammals. Initially, they form the apical ectodermal ridge, which soon regresses. The mesenchyme undergoes the process of condensation to form anlagens of prospective skeletal elements.” ↩
16.
Inamori, Daiki et al. “Second occurrence of a dolphin with fin-shaped hind appendages from waters off Taiji, the Pacific coast of Japan.” Cetacean Population Studies 4:1–2. Mar 29, 2023. A short communication, published online ahead of print on 29 March 2023, by staff of the Taiji Whale Museum, which holds the specimen. It describes a second striped dolphin with a pair of fin-shaped hind appendages, found in a January 2023 fishery harvest, and the authors promise fuller details in later reports. The article uses it for the second Taiji case and for the description of that animal's appendages.
1. 16a.
  Page 1: “Ohsumi and Kato (2008) reported on a very unique bottlenose dolphin (Tursiops truncatus) having fin-shaped hind appendages, captured from waters off Taiji ... Japan in 2006.” The primary is Seiji Ohsumi and Hidehiro Kato, "A bottlenose dolphin (Tursiops truncatus) with fin-shaped hind appendages," Marine Mammal Science 24(3):743–745, 2008, doi 10.1111/j.1748-7692.2008.00202.x. ↩
2. 16b.
  Page 2: “The dolphin (Taiji Whale Museum serial specimen ID 230105) was a male, 182 cm long”. “They were of similar size and shape, 4.3 cm (left side) to 5.8 cm (right side) in straight length, with the right one being slightly larger. The shape was similar to that of the pectoral flippers but more sticklike exterior”. ↩
17.
Wieland, Carl. “The strange tale of the leg on the whale.” Creation 20(3):10–13. Jun 1998. A 1998 magazine article by the creationist writer Carl Wieland that traces a story about a whale with a complete hind leg back to Robert Bakker's book The Dinosaur Heresies and then to E. J. Slijper's book Whales. It finds only a small bone inside a bump on a sperm whale, and it argues that a developmental defect can make extra bone but could not make an actual leg. The article uses it for Wieland's developmental-defect reply and for the test that his own model must pass.
1. 17a.
  “I knew, of course, that some modern whales have a pair of bones embedded in their tissues, each of which strengthens the pelvic wall and acts as an organ anchor”. “these strips of bone have a known function, differ in males and females, and are not even attached to the vertebral column.” ↩
2. 17b.
  “A mutational defect in this program could easily cause one or more extra pieces of bone to form, which would almost inevitably be in the same region, either separate from or fused with the normal bone. In the same way, people can be born with extra fingers, ribs, nipples, etc.” ↩
3. 17c.
  “such an explanation would be unable to cope with the occurrence in modern whales of an actual leg (internal or external), since this would clearly have design features which would never have been needed if the first whales were created.” ↩ ↩
4. 17d.
  “at Ayukawa Whaling Station (Japan), a Sperm Whale was brought in in 1956, with a 5-inch tibia projecting into a 5½-inch 'bump,' and a Russian factory ship in the Bering Sea had a similar experience in 1959.” The Ayukawa 1956 sperm whale is the specimen of Ogawa and Kamiya 1957. “Ignoring for the moment the purely anecdotal nature of the evidence”. ↩
18.
Surtees, Marc. “Whales designed or evolved: part 2—anatomy and genetics.” Journal of Creation 38(1):104–109. Apr 2024. The second part of a two-part article by Marc Surtees in the Journal of Creation, on the anatomy and genetics of whales. It argues that the whale features it covers, from the echolocation system to the reproductive organs, have no adequate evolutionary explanation, and it denies that the pelvic bones are vestigial legs. The article cites it for the denial of homology and for its claim that the historical reports of atavistic legs are unconfirmed.
1. 18a.
  Section Reproduction: “This is an appeal to homology which is not well supported by the evidence”. Section Vestigial legs?: Homology, as Surtees sets it out, requires three things: “same fundamental structure”. “same relationship to surrounding characters”. “same embryonic development”. “The bones are located within the body wall of the abdomen or the reproductive organs, which disqualifies them from being vestigial legs, since they are differently located with respect to other parts of the body.” ↩
2. 18b.
  Section Vestigial legs?: “But these historical accounts of atavistic legs have not been verified and there are no recent reports.” In the same paragraph, on the 2006 Taiji dolphin: “It is more likely that this was the result of a developmental defect which caused the growth of extra fins.” ↩
19.
Sarfati, Jonathan, and Don Batten. “'Vestigial' organs: what do they prove?” Creation Answers Book. Creation Ministries International. 2006. A section of the Creation Answers Book, written by Jonathan Sarfati and Don Batten for Creation Ministries International. The article uses it for the function reply, which it calls the oldest line of response to the vestigial argument.
1. 19a.
  Section Hip bones in whales: “These bones are alleged to show that whales evolved from land animals. However, Bergman and Howe point out that they are different in the male and female whales. They are not useless at all, but help penis erection in the males and vaginal contraction in the females.” The claim is Yablokov's, relayed. ↩
2. 19b.
  “even if the alleged vestigial organ were no longer needed, it would prove devolution not evolution.” ↩
20.
Thomas, Brian. “Vital Function Found for Whale 'Leg' Bones.” Institute for Creation Research. Oct 6, 2014. A short article by Brian Thomas, a science writer at the Institute for Creation Research, on a 2014 study of whale pelvic bones in the journal Evolution. Thomas reports the study's reasoning that species with relatively large male sexual organs need relatively large muscles and pelvic bones to anchor them, and he reads this as the bones being built for anchoring reproductive organs. The article cites it as part of the function reply.
1. 20a.
  “These results show that male whales use pelvis bones that were well crafted for anchoring reproductive organs—not for anchoring limbs. Whale hips are not vestigial.” ↩
21.
Answers in Genesis. Vestigial Structures. n.d. Retrieved Sep 26, 2026. An undated Answers in Genesis web page on vestigial structures, with a figure of a whale's pelvis. The article cites it in its treatment of the function reply.
1. 21a.
  “The figure on the left shows the supposed vestigial pelvis of a whale. Even though it has a clear reproductive function, evolutionists call it a left-over from a time when whales walked on land.” ↩
22.
Engler, Patricia. “Vestigial Organs: Evidence for Evolution (Part 5).” Answers in Genesis. Oct 7, 2020. A blog post by Patricia Engler in the Answers in Genesis series on vestigial organs. It sets out seven checks of critical thinking for judging vestigial-structure arguments, and it says that structures once called vestigial, such as the tailbone, the appendix and the whale pelvic bones, have functions. The article cites it for the function reply and for the charge that vestige arguments are circular.
1. 22a.
  “Even pelvic bones in whales serve essential reproductive functions, as a study reported in the journal Evolution the year after my textbook edition was published.” ↩
2. 22b.
  “So, these arguments must assume evolution is true in order to claim that evolution is true. Does anyone smell circular reasoning?” ↩
23.
Guliuzza, Randy. “Major Evolutionary Blunders: Are Whales and Evolution Joined at the Hip?” Institute for Creation Research. Feb 29, 2016. An article by Randy Guliuzza, the national representative of the Institute for Creation Research, that answers the Dines and Dean study of whale pelvic bones. It argues that calling the bones a pelvis is a mystical claim, because they are not attached to the backbone, and that co-option is a declaration rather than an observation. The article cites it as a creationist denial that the bones are a homologous pelvis.
1. 23a.
  Section Salvaging the Darwinian Whale Hip Story: “These 'hip' bones are not attached to the backbone of living whales, dolphins, or any of the fossils. Claims beyond the realm of human detection are mystical. The assertion that these bones are hip bones or a pelvis is a mystical claim.” The claim that no fossil whale's hip bones attach to the backbone is contradicted by Ambulocetus, which the whale evolution article treats. “Co-option is not an observation, it is a declaration.” ↩
24.
Wieland, Carl. “A dolphin with legs—NOT.” creation.com. Nov 6, 2006. A 2006 creation.com article by Carl Wieland about a dolphin found with a set of rear fins, which he says are fins and not legs. The article uses it for Wieland's answer to the 2006 Taiji dolphin, that today's two-finned dolphins may still carry the information for four fins.
1. 24a.
  “Today's two-finned dolphins may actually have the latent genetic information for generating all four fins. All dolphins may have once had two rear fins, and subsequently lost the information for generating them.” “The reality is that a dolphin was found with a nice-looking set of rear fins. Note—fins, not legs.” ↩
25.
Rana, Fazale. “Is the Whale Pelvis a Vestige of Evolution?” Reasons to Believe. Nov 17, 2014. A 2014 article by Fazale Rana, an old-earth creationist, for Reasons to Believe, on the 2014 Dines study of whale pelvic bones in the journal Evolution. Rana argues that the study shows the pelvis is functional and not vestigial, which he reads as the design of a Creator, and he states the evolutionary reply that the pelvis is still a homologous structure. The article cites it for that evolutionary reply.
1. 25a.
  “Evolutionary biologists will argue that this insight doesn't diminish the case for biological evolution one bit. They will maintain that the whale pelvis is a homologous structure, even if it isn't vestigial, and therefore supports common ancestry.” ↩