The Panda's Thumb | Berean Archive

"The sesamoid thumb wins no prize in an engineer's derby. It is, to use Michael Ghiselin's phrase, a contraption, not a lovely contrivance. But it does its job." (Stephen Jay Gould, The Panda's Thumb, 1980)¹

Summary

In 1980 Stephen Jay Gould made the giant panda's "thumb" the best-known example of an idea: odd, improvised structures prove evolution better than perfect ones do. The thumb is not a finger. It is the radial sesamoid, a wrist bone that in most carnivores is "a small, lens-shaped bone" and in the giant panda is about 35 millimetres long.²³ The parent article, Vestigial Structures, found that it is not a vestige on any definition. This article judges it as Gould meant it, as a bad-design argument, using the three steps of Arguments from Bad Design: state the task and the cost, compare a feasible alternative, and price the tradeoff.

Gould's claim was about history, not poor performance. He called the thumb "a somewhat clumsy, but quite workable, solution" that "does its job," forced on the panda because its true thumb was "committed to another role."¹ Behind it sat a premise about God: an ideal designer "would not have used a collection of parts generally fashioned for other purposes."¹
The thumb is one part of a wrist mechanism. Hideki Endo and colleagues showed from dissection and CT scans that the sesamoid does not move on its own. The whole hand folds at the wrist around it, giving "the virtual but functional opposability between the phalanges and the double pincers."⁴
It works quickly and precisely. D. Dwight Davis, Gould's own source, watched pandas handle single straws and candy discs "less than an inch in diameter."³ George Schaller's team timed wild pandas eating a whole bamboo shoot in 36.5 seconds on average.⁵
A real tradeoff holds it short, but nobody has priced it. Xiaoming Wang and colleagues described an ancestral panda's sesamoid longer than any living panda's. They argue the bone stopped growing "because it must be balanced with the constraints of weight bearing while walking in a plantigrade posture."⁶ No study has measured grip or walking cost for longer or shorter thumbs, and Wang's reason the tradeoff exists is that "the panda inherited a plantigrade posture."⁶
The foot changed too. The matching bone of the hind foot enlarged along with the thumb, and Davis called that growth "non-functional."³
Two pandas, two false thumbs. The red panda, which is not a bear, has one, and so did its fossil relative Simocyon.² Its discoverers read this as "an even more striking example" of Gould's point about history.²
The creationist replies. John Woodmorappe's best point, also argued in a 2023 philosophy paper, is that Gould's key premise is theology.⁷⁸ Other replies answer a claim Gould never made, that the thumb does not work. Answers in Genesis now places the giant panda in the bear kind and credits its diet to simple changes "such as larger jaw muscles and a bump on its wrist."⁹¹⁰ That concedes Gould's history and disputes only its timescale and cause.

Verdict: as a bad-design argument, the panda's thumb fails. Gould measured no shortfall, the grip is fast and precise, and its short length is plausibly explained by a weight-bearing tradeoff he did not know about. As an argument from history, it partly stands. The thumb is a remodelled wrist bone, its twin in the foot enlarged with no known use, and the best explanations of the tradeoff are inherited constraints. Young-earth creationists now accept that history within the bear kind. They have not explained the foot's side effect, and nobody on either side has priced the tradeoff.

Part 1: What Gould claimed

Gould's essay opens with Darwin's book on orchids. Orchids build insect traps and pollen launchers out of ordinary petals, and Gould drew the lesson in one paragraph: "If God had designed a beautiful machine to reflect his wisdom and power, surely he would not have used a collection of parts generally fashioned for other purposes. Orchids were not made by an ideal engineer; they are jury-rigged from a limited set of available components. Thus, they must have evolved from ordinary flowers."¹ He then stated the rule the essay defends: "Odd arrangements and funny solutions are the proof of evolution — paths that a sensible God would never tread but that a natural process, constrained by history, follows perforce."¹

The panda was his example. He watched the two pandas China sent to the Washington zoo strip bamboo "by passing the stalks between an apparently flexible thumb and the remaining fingers," and he was "amazed by their dexterity."¹ From Davis's monograph, which he called "probably the greatest work of modern evolutionary comparative anatomy," he took three facts.¹ The thumb "is not, anatomically, a finger at all" but "a bone called the radial sesamoid, normally a small component of the wrist."¹ Ordinary bears "already have a slightly enlarged radial sesamoid" with some of the same muscle attachments.¹ And Davis thought the enlargement "may have been fashioned by a simple genetic change, perhaps a single mutation affecting the timing and rate of growth."¹

The conclusion followed on page 24: "An engineer's best solution is debarred by history. The panda's true thumb is committed to another role, too specialized for a different function to become an opposable, manipulating digit. So the panda must use parts on hand and settle for an enlarged wrist bone and a somewhat clumsy, but quite workable, solution."¹ He did not say what the true thumb was committed to, except that "Carnivores run, stab, and scratch."¹

Three things matter here. Gould conceded function. "Somewhat clumsy" is his only performance claim, tied to no observation. And the inference from reused parts to history needs a premise about what "a sensible God" would do. Stephen Dilley of the Discovery Institute reconstructed the argument in 2023 and concluded that "both versions of the argument rest on a theological claim—namely, that God would not (likely) create or allow a suboptimal panda's thumb."⁸ He added that "nowhere in his writings does he provide a detailed empirical study that demonstrates the suboptimality of the panda's thumb."⁸ Both observations are accurate, and a test of the argument has to supply what Gould left out.

Why the thumb is filed among vestiges

The next essay in the same book, "Senseless Signs of History," applies the same reasoning to vestigial organs: "Remnants of the past that don't make sense in present terms — the useless, the odd, the peculiar, the incongruous — are the signs of history."¹ Vestiges and the panda's thumb sit side by side in that category, which is how the thumb came to be discussed alongside vestiges. But the parent article's test for a vestige asks for a homologue that has been reduced. The panda's sesamoid has been enlarged and given a new job. It fails the reduction step outright, so the vestige question does not arise. The live question is whether the thumb is a botch, and if not, whether its history still tells against design.

Part 2: What the thumb is made of

Davis, a curator at the Chicago Natural History Museum, based his 1964 soft anatomy mainly on one embalmed subadult male, Su Lin, from the Chicago zoo.³ He described the radial sesamoid as "the most extraordinary bone in the fore foot. It is about 35 mm. in length, and lies in line with the metacarpals, closely resembling a sixth metacarpal on the medial border of the hand."³ It has a true joint with the wrist, and on a ligament preparation "this bone could be manipulated through a range of about 20° of abduction-adduction, but was practically immobile in the direction of flexion-extension."³

Davis's reason for calling the mechanism simple was the muscles. In bears the long abductor tendon already ends partly in the sesamoid, and the short thumb muscles already attach to it. So "the musculature for operating this remarkable new mechanism — functionally a new digit — required no intrinsic change from conditions already present in the panda's closest relatives, the bears. Furthermore, it appears that the whole sequence of events in the musculature follows automatically from simple hypertrophy of the sesamoid bone."³

His reason for calling the genetics simple was the foot. The tibial sesamoid, the matching bone of the hind foot, "has no function corresponding to that of the radial sesamoid, yet as is evident from the figure it undergoes a corresponding increase in size."³ From that he inferred that "the genetic mechanism is a very simple one, perhaps involving no more than a single gene."³ This is an inference from two bones growing together, not a genetic finding, and no study found for this article has tested it.

Endo and colleagues at the National Science Museum in Tokyo reopened the anatomy. Their 1996 dissection of one old male found the sesamoid tied by fibrous tissue to the first metacarpal, and concluded that it "is only an elevated ridge or post opposite the 5 flexing digits and that it does not constitute an active mobile apparatus for grasping to any substantial extent."¹¹ In 1999 they CT-scanned the hand of an adult female carcass from the Ueno zoo, posed gripping a tube or stick 30 to 40 millimetres thick.⁴ The sesamoid, the radial carpal and the first metacarpal moved as one unit, and the accessory carpal and ulna as another, forming "a double pincer-like apparatus in the medial and lateral sides of the hand."¹² The fuller paper concluded: "In this refined system, the giant panda is equipped with the virtual but functional opposability between the phalanges and the double pincers."⁴ A 2001 study found the joint that lets the outer side of the hand fold as well.¹³

Endo's results come from single carcasses in posed grips. Mauricio Antón and colleagues objected in 2006 that one of Endo's muscle claims "seems to derive from observations on dead specimens where muscles are inert."¹⁴ Wang's team published a photograph of a living panda gripping bamboo and wrote that it "also shows that the pisiform plays no role in bamboo grasping, contra Endo et al."⁶ The details are still argued, but the main result is not. The grip depends "on the flexor muscles of the fingers, with the radial sesamoid acting as a passive stop against flexion of the fingers."⁶

Gould set a wrist bone beside an opposable thumb. The functional unit in the panda is the whole folding hand, and the sesamoid is its fixed jaw.

Part 3: How well it works

Davis gave a careful account: "The skill and precision with which objects are grasped and manipulated by the fore feet is astonishing. I have observed animals in the Chicago Zoological Park pick up small items like single straws and handle them with the greatest precision. Small disks of candy less than an inch in diameter were handled deftly and placed in the mouth."³ His verdict, "less clumsy than this comparison would indicate," is the opposite of Gould's "somewhat clumsy," though Gould cited Davis for everything else. Richard Perry's 1969 popular book repeats the straws and candy discs and adds a young panda using her thumb "to hold a spoon and ladle up her vegetable soup."¹⁵

Schaller's field study timed it. At the Wolong reserve, Schaller, Hu Jinchu, Pan Wenshi and Zhu Jing found that a captive named Ping-Ping took 36.6 ± 20.8 seconds per shoot over 77 shoots. "Pandas in the wild eat just as rapidly: in our study 14 shoots were consumed, on the average, in 36.5 ± 10.1 seconds."⁵ They added: "Forepaws and mouth work together with great precision, with great economy of motion".⁵ The demand is heavy: Wang's team gives intake as "up to 45 kg/day (depending on the season)" over about 15 hours a day of eating.⁶

So the hand does its central task well, though not everything. Wang's team calls the grip "far less effective than that of humans" and says pandas "never evolved sufficiently long false thumbs to seize large bundles of bamboo, a task that, while desirable, is not critical for survival."⁶⁶ What nobody has measured is the comparison the bad-design argument needs: how much faster or more securely a differently built hand would feed a panda.

Part 4: The tradeoff test

The task and the cost

The task is not "grasp like a human." It is to hold bamboo stems tightly against the twisting pull of the jaws, many thousands of times a day, on a forelimb that also walks flat-footed and climbs. Wang's team argues that grip strength is the point: "it seems likely that a tight grip is more critical to panda's feeding ability than the volume of their grasp."⁶ Davis added one relevant fact: the panda "does not pursue prey, and does not need to wander in search of food," so speed and range matter little.³ Load does matter. Schaller's team gives adult weights of "about 85-110 kg,"⁵ and the sesamoid sits under the palm on which the animal walks.

Feasible alternatives

Three alternatives appear in the literature.

The first is Gould's: a true opposable thumb. Gould said the panda's first digit was too specialized to become one. Antón's team says what it is specialized for. "The typical ursid hand consists of five subparallel digits lacking grasping abilities, owing to their adaptations for ambulatory terrestrial locomotion and digging."¹⁴ Primates show that an opposable first digit and four-footed walking can share one hand, so the alternative is not impossible in principle. What it would cost a clawed, 100-kilogram, flat-footed climber has never been estimated. Gould did not estimate it either; he assumed the cost from history.

The second is a longer sesamoid. Wang's team asked why pandas did not evolve one, since sesamoids "seem to be readily elongated with relatively little developmental constraint."⁶ The sesamoid of Ailurarctos from Shuitangba in Yunnan is 42.0 millimetres long against 31 to 39 in living pandas. Relative to body size, measured against the length of the second upper molar, it is 1.89 against 0.84 to 1.28. "Yet, modern pandas have a shorter radial sesamoid relative to their increased body size (as compared to their fossil ancestors), adding only a slight hook at the distal end."⁶ Their reason: "Due to its position in plantigrade posture, any further enlargement of the radial sesamoid would result in greater ventral protrusion and interference with walking."⁶ The living bone shows both demands: a hook on the gripping side, and a flattened walking surface under a fleshy pad that no other living bear has.⁶

The third is to take the wrist off the ground. Wang's team raised it themselves: "a digitigrade posture (lifting the palm off the ground, freeing the wrist area from weight bearing), as in cursorial carnivorans (canids, felids, hyaenids), but this may not have been feasible for ursids given their evolutionary history of plantigrady in addition to arboreality."⁶ A digitigrade panda would free the sesamoid, but it would give up the flat foot that bears use for climbing.

Pricing the tradeoff

Wang's paper turns "somewhat clumsy" from a verdict into a tradeoff with a mechanism: a gripping post that is also a walking surface cannot grow without getting in the way. The fossil shows the lineage moving toward a relatively shorter bone, which fits a compromise between two demands. On the grandparent's first two steps, Gould's criticism fails. He named no measured failure at the central task, and his alternative was never shown to improve that task without a loss.

The third step is incomplete on both sides. Wang's team offers the weight-bearing constraint as a proposal and warns "that the fossil record is too incomplete to allow a full understanding of this process."⁶ No one has measured grip force, how often stems slip, or the walking cost of sesamoids of different lengths. The tradeoff is identified, not priced. A defender of design can say a balance is struck, not that it is the best one.

Gould's argument still has force at three points. The thumb is built from a wrist bone, while the true first digit stays in line with the other fingers, its metacarpal locked to the sesamoid as one unit.¹⁴¹³ The tibial sesamoid in the foot enlarged in step, and Gould's summary is accurate: it "supports no new digit, and its increased size confers no advantage, so far as we know."¹ A designer aiming at the hand has no need to change the foot. Growth that spreads along a shared developmental field does, which is Davis's point. And the best explanations of the tradeoff are historical. Endo's team wrote that the panda "evolved from typical bear-like carnivores that did not display first metacarpal and digit opposability," and suggested that it "could not arrive at any solution other than the double-pincer mechanism."⁴ Wang's team explained the weight-bearing limit by inheritance too: "more efficient consumption of bamboo cannot override requirements for weight-bearing while walking because the panda inherited a plantigrade posture."⁶ They ended by saying Gould's "insightful remarks still stand" and that he "would probably have been delighted" by the tradeoff.⁶

Part 5: Two pandas, two thumbs

The red panda is a small tree-climber that also eats bamboo. It belongs to its own family, Ailuridae, and is not a bear.¹⁴ It too has an enlarged radial sesamoid, about 5.5 millimetres long in one measured skeleton.¹⁴ In 2006 Manuel Salesa and colleagues found the same enlarged bone in Simocyon batalleri, a puma-sized, partly tree-dwelling meat-eater from a Miocene carnivore trap near Madrid. They concluded that the ailurid false thumb began "as an aid for arboreal locomotion," with the red panda "secondarily developing its ability for item manipulation and thus producing one of the most dramatic cases of convergence among vertebrates."² Antón's team added the reason from the giant panda's side: "the need to manipulate food items was the main adaptive pressure leading to the selection of this highly specialized trait in Ailuropoda melanoleuca."¹⁴

Juan Abella and colleagues qualified this in 2015. They found moderately enlarged sesamoids in Indarctos, an early bear of the giant panda's line, and in the spectacled bear, civets and tree-climbing martens. So a middling sesamoid may be ancestral to all living bears, or to a wider group.¹⁶ On their reading, "the false thumb should not be interpreted as an anatomical convergence, but as an exaptive convergence regarding its use during the bamboo feeding."¹⁶ Both readings agree on two points. The giant panda's version is extreme, "almost as long as the first metacarpal."¹⁶ And the bamboo grip arose separately in the two lineages.

A second origin shows the solution is not a fluke. Enlarging a sesamoid is a route a carnivore's hand reaches readily, as Davis's genetic simplicity predicts. In that sense the parent article is right that a solution reached twice is less of an accident than Gould implied. But the discoverers draw the opposite lesson from the same finding. For Salesa's team, a thumb that began as a climbing aid and was reused for bamboo "provides an even more striking example of how evolution works opportunistically from the available materials."² A common designer reusing a good idea could also produce two similar thumbs. The double origin fits both readings, so it cannot decide between them.

Part 6: What the creationist replies say

Woodmorappe (1999). The fullest reply is John Woodmorappe's in the Journal of Creation. He split Gould's argument into five premises and wrote that "four of which are shown to be false."⁷ His strongest point is the first: Gould's claim about what God would do is untestable, which Dilley also argues. His second point fails. He wrote that "To say that the panda's thumb is a modified sesamoid bone already presupposes that the panda evolved from an ursine ancestor."⁷ The bone is identified by its joint with the scapholunar and its tendon, not by assuming a family tree. Answers in Genesis says the same thing without any ancestry: it "is simply an enlarged radial sesamoid — a wristbone."¹⁷ His third point answers a demand Gould did not make. "Pandas do not paint, type, write," he wrote, and "Were the Creator to have endowed the panda with a human-like thumb, this would be an instance of over-design."⁷ Gould's alternative was an opposable first digit of the kind primates keep, not human skills. Whether that digit would serve a panda better, and at what cost, is the question, and the reply does not engage it. Woodmorappe also misquotes Gould's key sentence as "clumsy, but workable solution," dropping the "quite" that concedes function.

Catchpoole (2001) and Sherwin (2005). David Catchpoole of Creation Ministries International wrote that the panda's thumb "serves them far more effectively in handling bamboo than a human thumb could."¹⁸ No measurement is given. Frank Sherwin of the Institute for Creation Research wrote that Gould "ignored the fact that panda bears have been doing just fine with this supposedly inferior structure."¹⁹ Gould did not ignore it; he wrote that "it does its job." Both replies refute a claim Gould did not make.

The kind question. The more consequential creationist writing is about where the panda sits. In 2001 Catchpoole set out the options: pandas may descend from a created bear kind, perhaps because "other bears have lost the genetic information for the thumb," or the thumb might "have arisen by mutations which resulted in distortion and enlargement of the wrist-bone," or pandas were "originally created as their 'own kind'". He favoured the last.¹⁸ Answers in Genesis now takes the first option. Jean Lightner's survey of Ark kinds in the Answers Research Journal says of the bears that "morphological and molecular evidence support" the giant panda's inclusion, and "the family seems to correspond to a kind."⁹ The red panda is its own kind.⁹ Melissa Webb, writing for Answers in Genesis, puts the change after the Flood: "As the bear kind diversified after the worldwide flood, the panda again adapted to a mostly herbivorous diet." She credits it to "simple changes to its body, such as larger jaw muscles and a bump on its wrist."¹⁰¹⁰

This position meets Gould's actual claim by accepting most of it. On the current young-earth model, the giant panda's thumb is a bear's wrist bone enlarged to meet a new diet, which is the history Gould inferred. The disagreement is over two things. One is time: a few thousand years on the creation model, against the six to seven million years Wang's team assigns to Ailurarctos.⁶ The other is cause: an unguided mutation, or a capacity for change built into the created kind, as Catchpoole's "lost the genetic information" option suggests.

Does the creation view have an answer beyond "it works"? In outline it does. A created bear kind able to enlarge a sesamoid when its diet changed would produce a working thumb quickly, and a matching enlargement in the foot, since the two bones share a growth control. But no creationist source found states that proposal, predicts the tibial sesamoid, prices the tradeoff, or engages Wang's fossil. Until one does, the reply is a possibility, not an explanation.

Objections and responses

"The hand is refined, so Gould was simply wrong." Endo's anatomy and Schaller's timings defeat "clumsy." They do not touch Gould's inference from reused parts to history, and Endo's own explanation of why the pincer was the only solution is ancestry.

"Calling it a sesamoid assumes evolution." The identification rests on the bone's joint, ligaments and tendon, and Answers in Genesis uses it too.

"Wang proves the thumb is optimal." Wang's team proposes a constraint and says the panda solution "may not be the most elegant."⁶ A tradeoff explains why a feature stops short of an ideal. It does not show the stopping point is the best one.

"The double origin proves a common designer." Convergence fits a designer reusing an idea, and it fits two lineages enlarging a bone that is easy to enlarge. The current creationist model already treats the giant panda's thumb as a change within the bear kind, so it too needs the second explanation for that lineage.

"An omnipotent designer could have made a hand that grips and walks perfectly." Perhaps. But "perfectly" has to be specified, and Gould never specified the better hand or its costs. The claim that a designer would never reuse parts is theology, as Dilley argues, and Arguments from Bad Design sets out why design does not by itself entail maximum performance.

"The foot's enlarged sesamoid is harmless, so it proves nothing." Harmless is not the point. A side effect with no use is what shared developmental control predicts and what a target-by-target design does not. It is the strongest item in Gould's case. The young-earth model can absorb it as a developmental change within the bear kind, which is what its own writers now propose, but not as special design of the hand.

"Pandas thrive, so the design is good." Pandas live on one food and absorb less than a fifth of its digestible matter.⁶ The thumb's success is local to one diet. That supports "workable," the word Gould chose, and no more.

Issues and unanswered questions

The tradeoff is unmeasured. No study found measures grip force, stem slippage, feeding rate or walking load against sesamoid length. Until one does, neither "clumsy" nor "well balanced" is a measured claim.
The anatomy rests on few animals. Davis's soft anatomy came mainly from one subadult male, Endo's from one carcass per study, Antón's from two red pandas. The fossil evidence for a shortening thumb is one Ailurarctos bone.
The single-gene claim is untested. Davis's "perhaps involving no more than a single gene" is an inference from the foot. No genetic study of sesamoid size in pandas was found.
Independent origin is disputed. Salesa and Antón read the two false thumbs as separate origins; Abella reads a shared, moderately enlarged ancestral bone reused twice.
The timescale is not addressed here. Wang's six to seven million years for Ailurarctos and the young-earth post-Flood timescale conflict. That is a dating question for other articles. This article does not settle it.
One quotation is unverified. A sentence that Woodmorappe, Catchpoole and Dilley attribute to Endo's 1999 Nature letter, calling the panda's grasp much more refined than earlier models suggested, is not in the letter's public abstract, and the letter itself could not be read. It is held in quarantine and not used here.
The creationist literature is thin. Beyond Woodmorappe and short magazine pieces, no creationist treatment of the tibial sesamoid, the weight-bearing constraint, the red panda's separate thumb or Ailurarctos was found. No article by Jerry Bergman on the panda's thumb was found.

Verdict

The panda's thumb is a weak bad-design argument and a moderate argument from history. Gould measured no shortfall, the hand lets a panda eat a bamboo shoot in under forty seconds with precision, and the thumb's short length is plausibly explained by a weight-bearing tradeoff, so "clumsy" does not survive. What survives is the observation that the thumb is a remodelled wrist bone and that its twin in the foot grew with it for no known use. The current young-earth model accepts that history within the bear kind and disputes its length and cause. To turn the thumb into positive evidence for design, a creationist would need to show why the foot changed, and to price the tradeoff against a real alternative. Neither has been done.

Sources

1.
Gould, Stephen Jay. “The Panda's Thumb.” The Panda's Thumb: More Reflections in Natural History, 19–26. W. W. Norton, New York. 1980. An essay in a book of essays, the first of two that the article cites from it. The article's subject is the essay's rule that odd arrangements and funny solutions prove evolution.
1. 1a.
  Page 20: “Orchids manufacture their intricate devices from the common components of ordinary flowers, parts usually fitted for very different functions. If God had designed a beautiful machine to reflect his wisdom and power, surely he would not have used a collection of parts generally fashioned for other purposes. Orchids were not made by an ideal engineer; they are jury-rigged from a limited set of available components. Thus, they must have evolved from ordinary flowers.” ↩ ↩
2. 1b.
  Pages 20–21: “But ideal design is a lousy argument for evolution, for it mimics the postulated action of an omnipotent creator. Odd arrangements and funny solutions are the proof of evolution — paths that a sensible God would never tread but that a natural process, constrained by history, follows perforce.” ↩
3. 1c.
  Page 21: “I was amazed by their dexterity and wondered how the scion of a stock adapted for running could use its hands so adroitly. They held the stalks of bamboo in their paws and stripped off the leaves by passing the stalks between an apparently flexible thumb and the remaining fingers.” Later in the same paragraph: “Carnivores run, stab, and scratch.” ↩ ↩
4. 1d.
  Page 22: Gould's words about Davis's 1964 monograph. “It is probably the greatest work of modern evolutionary comparative anatomy, and it contains more than anyone would ever want to know about pandas.” ↩
5. 1e.
  Page 22: “The panda's "thumb" is not, anatomically, a finger at all. It is constructed from a bone called the radial sesamoid, normally a small component of the wrist. In pandas, the radial sesamoid is greatly enlarged and elongated until it almost equals the metapodial bones of the true digits in length.” ↩
6. 1f.
  Page 23: “Moreover, ordinary bears already have a slightly enlarged radial sesamoid.” ↩
7. 1g.
  Page 23: “Moreover, Davis postulates that the enlarged radial sesamoid may have been fashioned by a simple genetic change, perhaps a single mutation affecting the timing and rate of growth.” ↩
8. 1h.
  Page 24: “In a panda's foot, the counterpart of the radial sesamoid, called the tibial sesamoid, is also enlarged, although not so much as the radial sesamoid. Yet the tibial sesamoid supports no new digit, and its increased size confers no advantage, so far as we know.” ↩
9. 1i.
  Page 24: “The panda's thumb provides an elegant zoological counterpart to Darwin's orchids. An engineer's best solution is debarred by history. The panda's true thumb is committed to another role, too specialized for a different function to become an opposable, manipulating digit. So the panda must use parts on hand and settle for an enlarged wrist bone and a somewhat clumsy, but quite workable, solution. The sesamoid thumb wins no prize in an engineer's derby. It is, to use Michael Ghiselin's phrase, a contraption, not a lovely contrivance. But it does its job and excites our imagination all the more because it builds on such improbable foundations.” ↩ ↩ ↩
10. 1j.
  Page 28: The second essay, "Senseless Signs of History," begins on p. 27. “But, Darwin reasoned, if organisms have a history, then ancestral stages should leave remnants behind. Remnants of the past that don't make sense in present terms — the useless, the odd, the peculiar, the incongruous — are the signs of history.” ↩
2.
Salesa, Manuel J. et al. “Evidence of a false thumb in a fossil carnivore clarifies the evolution of pandas.” PNAS 103(2):379–382. Jan 10, 2006. A report of new fossils from Batallones-1, a Miocene site near Madrid, by a team at the Madrid natural history museum. The fossils come from two individuals of Simocyon batalleri, a puma-sized, partly tree-dwelling meat-eater whose enlarged wrist bone resembles the red panda's, and the team concluded that the false thumbs of the fossil and the red panda began as climbing aids, while the giant panda's probably evolved for bamboo. The article uses it to show that the thumb arose a second time, and for the authors' reading that the red panda later reused its thumb for bamboo.
1. 2a.
  Page 379, section Abstract: “The radial sesamoid of S. batalleri shows similarities with that of the red panda, which supports a sister-group relationship and indicates independent evolution in both pandas. The fossils from Batallones-1 reveal S. batalleri as a puma-sized, semiarboreal carnivore with a moderately hypercarnivore diet. [...] Thus, it seems that, whereas the false thumb of the giant panda probably evolved for manipulating bamboo, the false thumbs of the red panda and of S. batalleri more likely evolved as an aid for arboreal locomotion, with the red panda secondarily developing its ability for item manipulation and thus producing one of the most dramatic cases of convergence among vertebrates.” Section First paragraph, page 379: “The fossil site of Batallones-1 (Madrid) is a Miocene carnivore trap”. ↩ ↩
2. 2b.
  Page 380: “In all known carnivores, other than the pandas and Simocyon, the radial sesamoid retains its primitive state as a small, lens-shaped bone that develops on the tendon of the abductor pollicis longus muscle where it glides over the scapholunar.” Abella and colleagues 2015 report moderately enlarged radial sesamoids in some other carnivores; see Part 5. ↩
3. 2c.
  Page 381: “Over a quarter of a century ago, Stephen Jay Gould celebrated the concept of contingency in evolution as illustrated by the development of the giant panda's false thumb (31). The evidence presented in this article, indicating that the false thumb of the red panda did not originally evolve for its present function of grasping bamboo, but rather shifted from its earlier function as an aid in arboreal locomotion, provides an even more striking example of how evolution works opportunistically from the available materials.” ↩ ↩
3.
Davis, D. Dwight. “The Giant Panda: A Morphological Study of Evolutionary Mechanisms.” Fieldiana: Zoology Memoirs 3. Chicago Natural History Museum. Dec 7, 1964. A monograph on the giant panda's anatomy by a curator at the Chicago Natural History Museum, and the study Gould drew on for his account of the thumb. It is based largely on one embalmed body, Su Lin, a subadult male from the Chicago zoo, so its soft-anatomy claims rest mainly on that one animal. The article uses it for the size and joint of the radial sesamoid, and for Davis's report that the matching bone of the foot enlarged without a function.
1. 3a.
  Page 13: “This study is based largely on the embalmed and injected body of a giant panda that lived in the Chicago Zoological Park from February, 1937, to April, 1938. The panda was popularly known as Su Lin. Unless otherwise stated, all statements relating to the soft anatomy are based on this specimen. Su Lin was a subadult male (teeth fully erupted).” ↩
2. 3b.
  Page 22: “It has practically no natural enemies, does not pursue prey, and does not need to wander in search of food. Demands on locomotor efficiency are absolutely minimal.” ↩
3. 3c.
  Page 23: “The skill and precision with which objects are grasped and manipulated by the fore feet is astonishing. I have observed animals in the Chicago Zoological Park pick up small items like single straws and handle them with the greatest precision. Small disks of candy less than an inch in diameter were handled deftly and placed in the mouth. Objects are grasped between the radial pad and the palmar pad and are held in the shallow furrow that separates these two pads. The actions of the fore paw suggest a human hand grasping through a thumbless mitten but are less clumsy than this comparison would indicate.” ↩ ↩
4. 3d.
  Page 99: “The radial sesamoid (fig. 54) is the most extraordinary bone in the fore foot. It is about 35 mm. in length, and lies in line with the metacarpals, closely resembling a sixth metacarpal on the medial border of the hand.” ↩ ↩
5. 3e.
  Page 100: “The tibial sesamoid has no function corresponding to that of the radial sesamoid, yet as is evident from the figure it undergoes a corresponding increase in size. This indicates a genuine serial homology between these two bones, with a common genetic control of the size factor at least”. ↩
6. 3f.
  Page 123: “The localized remodeling seen in the sesamoid surely has a specific genetic base, as is strongly indicated by the "sympathetic" hypertrophy of the tibial sesamoid. The parallel and non-functional hypertrophy of the tibial sesamoid also indicates that the genetic mechanism is a very simple one, perhaps involving no more than a single gene.” ↩ ↩
7. 3g.
  Page 139: “The articulation between the radial sesamoid and the scapholunar is a true diarthrosis, capable of quite extensive movements of abduction and adduction, but probably incapable of dorsal and volar flexion. On a ligamentary preparation this bone could be manipulated through a range of about 20° of abduction-adduction, but was practically immobile in the direction of flexion-extension.” ↩
8. 3h.
  Pages 182–183: “Thus, the musculature for operating this remarkable new mechanism — functionally a new digit — required no intrinsic change from conditions already present in the panda's closest relatives, the bears. Furthermore, it appears that the whole sequence of events in the musculature follows automatically from simple hypertrophy of the sesamoid bone.” ↩
4.
Endo, Hideki et al. “CT examination of the manipulation system in the giant panda (Ailuropoda melanoleuca).” Journal of Anatomy 195(2):295–300. 1999. A computed tomography study (CT, X-ray scans rebuilt into 3-D images) of the hand of a single adult female giant panda carcass from Ueno Zoological Park, scanned while it gripped a tube or stick. It found that the radial sesamoid, radial carpal and first metacarpal move as one unit, and that the accessory carpal and ulna form a second unit, which the authors call double pincers. The article uses it for the point that the thumb is one part of a wrist mechanism.
1. 4a.
  Page 295: “The carcass of an adult female giant panda was donated to National Science Museum, Tokyo, from Ueno Zoological Park (Tokyo, Japan).” Page 296: “The hand was artificially positioned on the CT scanning machine in both opened and gripped states. The carcass hand gripped the centrifuge tube or a plastic stick 30–40 mm in diameter to reproduce the manipulating state.” ↩
2. 4b.
  Page 299: “The RS and AC are not active manipulators independent of the bones with which they articulate in any gripping state, but constitute functional complexes. We can conclude that the giant panda flexes and extends the doubler pincer-like apparatus, the R–R–M complex and the A–U complex, during the action of grasping. In this refined system, the giant panda is equipped with the virtual but functional opposability between the phalanges and the double pincers.” "doubler" is printed that way in the source [sic]. ↩ ↩
3. 4c.
  Page 299: “This species evolved from typical bear-like carnivores that did not display first metacarpal and digit opposability in their hand structure. The adaptation for a herbivorous diet required the species to skilfully manipulate bamboo stems in Asian forests. We suggest that the panda could not arrive at any solution other than the double-pincer mechanism.” ↩
5.
Schaller, George B. et al. The Giant Pandas of Wolong. University of Chicago Press. 1985. A book by four authors who studied giant pandas at the Wolong reserve. They timed a captive panda named Ping-Ping and wild pandas eating bamboo shoots, and they recorded adult weights. The article uses their timings to show that pandas feed quickly and precisely.
1. 5a.
  Page 17: “Pandas are robust, bearlike animals, weighing about 85-110 kg, whose specialized physical features include broad, flat molars, modified for crushing, and an enlarged wrist bone functioning as a thumb”. ↩
2. 5b.
  Page 57: “Between 18 and 20 May, we fed the captive Ping-Ping 77 shoots [...] Average eating time was 36.6 ± 20.8 (range 10-110) seconds per shoot, but average total time per shoot, including activities other than preparing and eating the shoot, was 50 seconds (table 3.7). Pandas in the wild eat just as rapidly: in our study 14 shoots were consumed, on the average, in 36.5 ± 10.1 seconds.” ↩ ↩
3. 5c.
  Page 58: “When watching a panda eat leaves, stem or new shoots we were always impressed by its dexterity. Forepaws and mouth work together with great precision, with great economy of motion, as the food is grasped, plucked, peeled, stripped, bitten and otherwise prepared for being swallowed.” ↩
6.
Wang, Xiaoming et al. “Earliest giant panda false thumb suggests conflicting demands for locomotion and feeding.” Scientific Reports 12:10538. 2022. A report of a late Miocene fossil panda, Ailurarctos, from Shuitangba in Yunnan, China, with an enlarged wrist bone that is the earliest of its kind in the panda line. The authors argue that the bone stopped growing because it must carry weight when the animal walks on the whole sole (a plantigrade posture), so the thumb serves both for bamboo and for weight bearing. The article uses it for the argument that a real tradeoff holds the thumb short, and for the authors' view that the panda's grip is 'far less effective' than a human's.
1. 6a.
  Page 1, section Abstract: “We report the earliest enlarged radial sesamoid, already a functional opposable "thumb," in the ancestral panda Ailurarctos from the late Miocene site of Shuitangba in Yunnan Province, China. However, since the late Miocene, the "thumb" has not enlarged further because it must be balanced with the constraints of weight bearing while walking in a plantigrade posture. This morphological adaptation in panda evolution thus reflects a dual function of the radial sesamoid for both bamboo manipulation and weight distribution. The latter constraint could be the main reason why the panda's false thumb never evolved into a full digit. This crude "thumb" suggests that the origin of the panda's dedicated bamboo diet goes back to as early as 6–7 Ma.” ↩ ↩
2. 6b.
  Page 1: “If bamboo manipulation is the main function of this feature, why did pandas not evolve a markedly more elongated radial sesamoid, one that more closely resembles a true opposable thumb for the efficient gripping of bamboo, given that mammalian sesamoids seem to be readily elongated with relatively little developmental constraint?” ↩
3. 6c.
  Page 5: “Such a passive system of gripping, far less effective than that of humans, nonetheless offers the panda the tightness of grip it needs for bamboo feeding.” ↩
4. 6d.
  Page 6: “The radial sesamoid in Ailurarctos exceeds that of its modern descendants, both in absolute and relative size (radial sesamoid index = 1.89 for Ailurarctos from Shuitangba; 0.92 for Shuanghe Cave fossil; 0.84–1.28 for living Ailuropoda melanoleuca) (Tables 1, 2). If a longer radial sesamoid alone was being selected, it would be expected that modern pandas would have increased the length of the radial sesamoid in the intervening six million years. Yet, modern pandas have a shorter radial sesamoid relative to their increased body size (as compared to their fossil ancestors), adding only a slight hook at the distal end.” Table 2 gives the greatest length as 42.0 mm for Ailurarctos and 31–39 mm for modern Ailuropoda melanoleuca. ↩
5. 6e.
  Page 6: “Due to its position in plantigrade posture, any further enlargement of the radial sesamoid would result in greater ventral protrusion and interference with walking.” ↩
6. 6f.
  Page 6: “As illustrated in the evolution of the false thumb (Fig. 5), more efficient consumption of bamboo cannot override requirements for weight-bearing while walking because the panda inherited a plantigrade posture.” ↩ ↩
7. 6g.
  Page 6: “Potential alternatives to overcome such a constraint include a digitigrade posture (lifting the palm off the ground, freeing the wrist area from weight bearing), as in cursorial carnivorans (canids, felids, hyaenids), but this may not have been feasible for ursids given their evolutionary history of plantigrady in addition to arboreality.” ↩
8. 6h.
  Page 8, figure 6: The words are from the figure caption. “This photo also shows that the pisiform plays no role in bamboo grasping, contra Endo et al.” ↩
9. 6i.
  Page 8: “Of the living ursids, only the giant pandas have a large fleshy pad (Fig. 6) to cushion the radial sesamoid, signaling the importance of the weight-bearing function for this bone. While the panda solution may not be the most elegant, its functionality is evidenced by a long history of at least 6–7 million years (Fig. 1).” ↩ ↩
10. 6j.
  Page 8: “Therefore, it seems likely that a tight grip is more critical to panda's feeding ability than the volume of their grasp.” ↩
11. 6k.
  Page 10: “The strength of the giant panda grip is dependent on the flexor muscles of the fingers, with the radial sesamoid acting as a passive stop against flexion of the fingers.” ↩
12. 6l.
  Page 10: “Because of the functional constraints imposed on the length of the radial sesamoid noted above, pandas never evolved sufficiently long false thumbs to seize large bundles of bamboo, a task that, while desirable, is not critical for survival.” ↩
13. 6m.
  Page 10: “To make this tradeoff work, pandas eat prodigious quantities of bamboo, up to 45 kg/day (depending on the season), and spend ~ 15 h/day eating. The panda's short digestive tract, inherited from its carnivoran ancestors, is also poorly suited for extracting nutrients, absorbing less than 20% of digestible dry matter.” ↩ ↩
14. 6n.
  Page 11: “We caution, however, that the fossil record is too incomplete to allow a full understanding of this process and future discoveries will likely reveal unforeseen details.” ↩
15. 6o.
  Page 11: “Steven [sic] J. Gould's insightful remarks still stand”. Later in the same paragraph. “However, he would probably have been delighted to learn that the historic contingency of the panda's false thumb requires that while being a better finger was favored by selection, it also had to bear the burden of considerable body weight.” ↩
7.
Woodmorappe, John. “The panda thumbs its nose at the dysteleological arguments of the atheist Stephen Jay Gould.” Journal of Creation 13(1):45–48. Apr 1999. A reply, in the Journal of Creation, to Gould's arguments from supposed bad design (dysteleology). Its opening summary says that Gould's case rests on five premises, four of which the author says are false. The article uses it as the fullest creationist reply to Gould, and calls its first point the strongest and its second point a failure.
1. 7a.
  Section Opening summary: “Evolutionists have argued that this arrangement is bad design, and so the panda would not have been created but must have evolved. However, their argument is based on five premises, four of which are shown to be false.” Section Main text: “Premise [1] is completely untestable. There is no way of knowing, apart from revelation (which we do not have about this issue), the specifics of what God would or would not do when creating something.” ↩ ↩
2. 7b.
  Section Main text, before the heading "Correct functions": “To say that the panda's thumb is a modified sesamoid bone already presupposes that the panda evolved from an ursine ancestor having a 'normally small' sesamoid wrist bone.” ↩
3. 7c.
  Section Correct functions: “Pandas do not paint, type, write, or do countless other things which humans do with their hands.” “Were the Creator to have endowed the panda with a human-like thumb, this would be an instance of over-design.” Woodmorappe's quotation of Gould in the same article reads "a somewhat [5] clumsy, but workable solution"; Gould's p. 24 reads "a somewhat clumsy, but quite workable, solution." ↩
8.
Dilley, Stephen. “God, Gould, and the Panda's Thumb.” Religions 14(8):1006. 2023. A 2023 philosophy paper in the journal Religions that rebuilds Gould's panda argument in two forms and argues that both rest on a claim about what God would do. Its author is at the Discovery Institute, which funded the paper. The article uses it as the fullest recent form of Woodmorappe's point that Gould's key premise is theology.
1. 8a.
  Page 1, section Abstract: “I contend that both versions of the argument rest on a theological claim—namely, that God would not (likely) create or allow a suboptimal panda's thumb.” ↩ ↩
2. 8b.
  Page 11: “Oddly, Gould does not give strong reasons to accept this claim; nowhere in his writings does he provide a detailed empirical study that demonstrates the suboptimality of the panda's thumb.” ↩
9.
Lightner, Jean K. “Mammalian Ark Kinds.” Answers Research Journal 5:151–204. 2012. A survey of mammal families as the "kinds" that were on Noah's Ark, in which each family is treated as one kind. The article uses its entry on the bears to show where creationists now place the giant panda.
1. 9a.
  Page 188, section Ursidae (Bear kind): “Some have questioned the inclusion of the giant panda in this family because it has some unique characteristics. However, morphological and molecular evidence support its inclusion here (Wilson and Reeder 2005). Hybrid data connect all species except the giant panda (Hennigan 2010). Based on the extensive hybrid data and strong cognitum, the family seems to correspond to a kind.” ↩ ↩
2. 9b.
  Page 189, section Ailuridae (Red panda kind): “This monotypic family contains only the red panda, which has previously been placed in Procyonidae.” ↩
10.
Webb, Melissa. Giant Panda: The Veggie Bear. Answers in Genesis. Jan 1, 2020. A web article from Answers in Genesis about the panda's diet. It says the bear kind diversified after the Flood and that the panda changed its diet through simple changes to its body. The article uses it for the claim that a jaw muscle and a bump on the wrist were enough for the diet change.
1. 10a.
  Section Opening section: “As the bear kind diversified after the worldwide flood, the panda again adapted to a mostly herbivorous diet like its ancestors in Eden.” ↩
2. 10b.
  Section You Are What You Eat: “These new studies help explain how the panda was able to change its diet quickly with simple changes to its body, such as larger jaw muscles and a bump on its wrist.” ↩ ↩
11.
Endo, Hideki et al. “Functional anatomy of the radial sesamoid bone in the giant panda (Ailuropoda melanoleuca).” Journal of Anatomy 189:587–592. 1996. A dissection study by a team at the National Science Museum in Tokyo, of one male giant panda estimated at over 25 years old and about 150 kg, which died at Ueno Zoological Park. The team examined the bones and muscles by eye and with radiographs, and found the sesamoid tied by a fibrous joint (a joint held by tough connective tissue, not a free-moving one) to the first metacarpal, so it cannot move on its own. The article's account of the reopened anatomy starts with this dissection.
1. 11a.
  Page 592: “We conclude that the RS is only an elevated ridge or post opposite the 5 flexing digits and that it does not constitute an active mobile apparatus for grasping to any substantial extent.” ↩
12.
Endo, Hideki et al. “Role of the giant panda's 'pseudo-thumb'.” Nature 397:309–310. Jan 28, 1999. A Scientific Correspondence, a brief letter in Nature, by the same Tokyo team. It used computed tomography (CT, X-ray scans rebuilt into 3-D images) and magnetic resonance imaging on one panda hand, and found that the radial sesamoid cannot move independently of the bones it joins. The article uses it for the double-pincer picture of how the hand grips.
1. 12a.
  Section Abstract, page 309: “The three-dimensional images we obtained indicate that the radial sesamoid bone cannot move independently of its articulated bones, as has been suggested, but rather acts as part of a functional unit of manipulation. The radial sesamoid bone and the accessory carpal bone form a double pincer-like apparatus in the medial and lateral sides of the hand, respectively, enabling the panda to manipulate objects with great dexterity.” ↩
13.
Endo, Hideki et al. “Carpal bone movements in gripping action of the giant panda (Ailuropoda melanoleuca).” Journal of Anatomy 198(2):243–246. 2001. A short report from the same Tokyo team, using CT scans of a female carcass's forelimbs and bone specimens to follow the wrist bones while the hand gripped a tube or stick 30 to 40 mm thick. It found that the radial carpal and fourth carpal bones rotate or flex toward the radial and ulnar sides, letting the panda bend its palm from the forearm to grip. The article uses it for the point that the sesamoid moves together with the first metacarpal, not on its own.
1. 13a.
  Page 244: “The 1st metacarpal flexes with the radial carpal and the radial sesamoid and thus the radial sesamoid does not move independently of the 1st metacarpal.” ↩
2. 13b.
  Page 246: “The present data demonstrate that the distal part, including the radial sesamoid, crooks the wrist from the proximal part, including the accessory carpal, enabling the panda to skilfully manipulate objects.” ↩
14.
Antón, Mauricio et al. “Implications of the functional anatomy of the hand and forearm of Ailurus fulgens (Carnivora, Ailuridae) for the evolution of the 'false-thumb' in pandas.” Journal of Anatomy 209(6):757–764. 2006. A dissection study of the red panda (Ailurus fulgens) by anatomists in Madrid and Valladolid, who dissected two animals and combined that with CT scans and a skeleton. They found that the enlarged bone has a real joint with a wrist bone, which an earlier study had misread, and that some of the red panda's hand features are climbing adaptations later put to use on bamboo. The article uses it for the authors' objection that one claim by Endo and colleagues came from dead animals, and for the red panda's bone, about 5.5 millimetres long.
1. 14a.
  Page 757, section Abstract: “Both the giant panda (Ailuropoda melanoleuca) and the red panda (Ailurus fulgens) possess a 'false-thumb', actually an enlarged radial sesamoid bone, which contributes to the gripping action of the hand. These species are not closely related, however, as one is an ursid and the other an ailurid, so the fact that they share this adaptation implies a remarkable convergence.” ↩
2. 14b.
  Page 757: “The 'false-thumb' is a small bone, the radial sesamoid, that is present in many carnivores, which has enlarged in pandas, contributing to gripping actions, and compensating for the lack of prehensile abilities in a hand where the pollex is aligned with the other digits.” ↩
3. 14c.
  Page 758: “The radial sesamoid of Ailurus fulgens, although enlarged in relation to other carnivores, is a small bone (Fig. 1), measuring about 5.5 mm in maximum length in our specimen 2031.” ↩
4. 14d.
  Page 760: “The suggestion by Endo et al. (1999a, p. 299) that the muscles abductor pollicis brevis and opponens pollicis would act as 'a cushion for objects grasped between the radial sesamoid and the first metacarpal' seems to derive from observations on dead specimens where muscles are inert, whereas in live animals the contraction implies a shortening of the fibres, not a folding.” ↩
5. 14e.
  Page 762: “The typical ursid hand consists of five subparallel digits lacking grasping abilities, owing to their adaptations for ambulatory terrestrial locomotion and digging (Gambaryan, 1974).” ↩
6. 14f.
  Page 762: “But the development of an hypertrophied radial sesamoid in an essentially ursid hand in the giant panda reflects a very different evolutionary scenario to that of the ailurids, suggesting that the need to manipulate food items was the main adaptive pressure leading to the selection of this highly specialized trait in Ailuropoda melanoleuca.” ↩
15.
Perry, Richard. The World of the Giant Panda. Taplinger, New York. 1969. A 1969 book about the giant panda. Its account of the panda's skill repeats the straws and candy discs and adds a young panda that used her thumb to hold a spoon. The article uses it as a second witness to the precision of the panda's grip.
1. 15a.
  Pages 76–77: “A beishung can therefore grasp and manipulate objects with astonishing adeptness, using one or both hands to hold his length of culm or, in captivity, sugar-cane or slice of bread [...] Ming., when young, is reported to have used her thumb to hold a spoon and ladle up her vegetable soup; and certainly the smallest objects, such as single straws or candy-discs less than an inch in diameter, can be picked up and handled with the utmost precision.” ↩
16.
Abella, Juan et al. “Tracing the origin of the panda's thumb.” The Science of Nature 102:35. 2015. A study of 13 fossil radial sesamoids of Indarctos arctoides, an early bear of about 9 million years ago from the Batallones-3 site near Madrid, representing at least eight animals. It found that this bear's sesamoid was relatively enlarged, shaped more like the red panda's and other carnivores' than the giant panda's. The article uses it for the authors' view that the two pandas' thumbs are an 'exaptive convergence' in their bamboo feeding, and for the suggestion that a middling sesamoid may be ancestral to bears.
1. 16a.
  Page 1, section Abstract: “Moreover, in the two extant pandas, the false thumb should not be interpreted as an anatomical convergence, but as an exaptive convergence regarding its use during the bamboo feeding, which changes the evolutionary view of this singular structure.” ↩
2. 16b.
  Page 6: “First, the giant panda differs from all the remaining taxa in having an extremely hypertrophied radial sesamoid, which is almost as long as the first metacarpal (Table 1).” ↩
3. 16c.
  Page 9: “On the other hand, the possession of similarly enlarged radial sesamoids in both the early ailuropodine Indarctos and extant tremarctine bears suggests that a moderately well-developed radial sesamoid is likely to represent the plesiomorphic condition for crown ursids as a whole”. Page 10: “This suggests that the somewhat hypertrophied configuration of the Late Miocene ursid I. arctoides and the other carnivorans with well-developed radial sesamoids could be interpreted as the symplesiomorphic condition for the Arctoidea.” ↩
17.
Answers in Genesis. “Why Pandas Have Six Fingers.” Creation 17(2):39. Mar 1995. An unsigned article from Answers in Genesis on the panda's "sixth finger". It calls the extra "thumb" an enlarged radial sesamoid, a small bone that forms in a tendon, and says it is larger in the giant panda because the giant panda eats larger stems. The article uses it because it identifies the thumb as a sesamoid without assuming an ancestor, as Woodmorappe does.
1. 17a.
  Section Main text: “The 'sixth finger', or pseudo-thumb, is simply an enlarged radial sesamoid — a wristbone that helps the panda grasp the bamboo stems it eats. This 'thumb' is larger in the giant panda because it eats larger bamboo stems.” ↩
18.
Catchpoole, David. “The bamboozling panda.” Creation 23(2):28–32. Mar 2001. An article in Creation that sets out where the giant panda might sit among the bears. The article uses it for two points: the claim that the panda's own thumb works better than a human thumb would, and the options for the panda's place among the bears.
1. 18a.
  Section How much evolution can a panda bear?: “Though creationists are open to the idea that the giant panda is descended from a more generalized ancestral bear 'kind', we can't be sure. [...] Could it be that other bears have lost the genetic information for the thumb, which was present in the originally created bear 'kind'? Or could the appendage have arisen by mutations which resulted in distortion and enlargement of the wrist-bone?” “My assessment therefore is that giant pandas were originally created as their 'own kind', already endowed with their distinctive characteristics that suit them superbly to their specialized mode of life.” ↩
2. 18b.
  Section Box "Pandas thumb their nose at evolution": “Consequently, they do not need a human thumb—indeed, their own 'thumb' serves them far more effectively in handling bamboo than a human thumb could.” ↩
19.
Sherwin, Frank. That Troubling Laryngeal Nerve? Institute for Creation Research. May 1, 2005. A web article by Frank Sherwin of the Institute for Creation Research, which says Gould repeatedly cited the panda's thumb as a corrupt feature. Its note 2 cites Gould's 1987 essay "The Panda's Thumb of Technology", which is about typewriter keyboards, not the 1980 essay. The article uses it for the reply that pandas do just fine with their thumb.
1. 19a.
  Section Second paragraph: “The late S. J. Gould repeatedly cited this allegedly corrupt feature, but he ignored the fact that panda bears have been doing just fine with this supposedly inferior structure.” ↩