Whence the giant panda?

Posted 14 May 2004 by Reed A. Cartwright

↗ The current version of this post is on the live site: https://pandasthumb.org/archives/2004/05/whence-the-gian.html

Well our first poll is over and the majority of the five hundred and nine votes cast say that giant pandas are not bears: 28% yes, 62% no, and 10% dunno. I hate to say it, but the majority is wrong.

Giant pandas (Ailuropoda melanoleuca) form the most basal branch of the bear family. The figure below shows the relationship of the bears to the rest of the extant order Carnivoria (Mammalia). It is the composite of two maximum parsimony phylogenies, Figures 1 and 8 of Bininda-Emonds et al. (1999), derived from data present in scientific literature. The scale of the tree is millions of years before present and was derived from data in Tables 2 and 9 of Bininda-Emonds et al. (1999).

The giant panda first appears in the fossil record about 3 million years ago during the Early Pleistocene. It had a wide distribution in the Pleistocene ranging from Myanmar to eastern China and as far north as Beijing (Schaller et al. 1985 p11 ). The giant panda lineage branched off from the other bears around 22 million years ago (Bininda-Emonds et al. 1999). It has been suggested that the giant panda is a descendent of Agriarctos, a “small, bearlike animal of the Ursavus lineage from the mid-Miocene in Europe” and the last surviving member of Ursidae subfamily, Agriotherinnae (Schaller et al. 1985 p229).

Although, there used to be a debate on whether the giant panda was more closely related to raccoons or to bears, multiple studies since the 1960s established its connection to the other bears. In 1869 the giant panda was first discovered by western zoologists and described as a new species of Ursus. However, the next year another zoologist claimed that the giant panda was not a bear but a relative of the red panda, which was at that time believed to be related to raccoons. In 1964, D. D. Davis published a comprehensive, comparative anatomical study that showed that the giant panda was a bear adapted for a particular food niche. After that, only a few zoologists held on to the idea that they two pandas were close relatives (Mayr 1986). Molecular studies beginning in the mid 1980s helped support the conclusion of anatomists and paleontologists.

O’Brien et al. (1985) used DNA-DNA hybridization, isozyme genetic distance, immunological distance, and karyotype evidence to estimate the relationships among the giant panda, red panda, and their supposed closest relatives. They concluded that the giant panda’s closest relative were the other bears.

Molecular and cytological methods specify the divergence of the giant panda from the ursid lineage of the carnivores at 15-25 Myr BP, whereas ancestors of the [red] panda emerge very near the time of the procyonid-ursid split.

(O'Brien et al. 1985)

Wayne et al. (1989) used similar methods to study a larger picture of carnivore evolution and similiarly concluding that the giant panda was a basal lineage of the bears.

The consensus treee indicates that between 30 and 40 M.Y.B.P. the progenitor of modern ussids and procyonids split into two lineages. Within 10 million years of that event the procyonid group split into Old World procyondis represented today by the red panda and the New World procyonids (for example, raccoons, coatis, olingos, kinkajous). Approximately 18-25 M.Y.B.P. the ancestor of the giant panda … diverged from the ursid line. The next divergence is between teh ursine bears and the spectacled bear … which occured between 12-15 M.Y.B.P. The lineages leading to the remaining species—the brown bear … the black bear … the sun bear … and the sloth bear … —first became distinct 5-7 M.Y.B.P.

(Wayne et al. 1989)

Goldman et al. (1989) used one- and two-dimensional protein electrophoresis to estimate the molecular distance among the eight species of bears, raccoon, and red panda.

The addition of two new data sets relating 289 proteins resolved by 2-D gels and 44 allozyme systems from living ursid species plus two procyonid species provides a corroborative basis for interpreting the evolutionary history of this group. The results were in topological agreement with each other and with previous phonetic trees derived using DNA hybridization, albumin immunological distance, and allozyme genetic distance (Sarich, 1973; O’Brien et al., 1985). The cumulative data suggestions an ancient ologocene split of the ursid and procyonid progenitors. Within then million years of that event, the red panda diverged from the lineage that lead to the raccoon. Modern procyonids consist of 19 distanct species, and all but the red panda are found in the New World (Nowak and Paradiso, 1983).

Within the ursid radiation, there are three primary divergence nodes that consistently appear. The earliest is the line that lead to the giant panda, the second lead to the spectacled bear, and the third is a polytypic divergence node with lead to the speciation of size species of usine bears. The divergence relationship among ursine bears was not resolved with any of the molecular data sets with the exception of the affirmation of the close affinity of the brown bear and the polar bear.

(Goldman et al. 1989)

Hashimoto et al. (1993) studied alpha- and beta-hemoglobin sequences from various carnivores using maximum likelihood. They also concluded that the giant panda’s closest relatives were the other bears.

And finally, in a recent study using DNA fingerprinting, Wan et al. (2003) conclude that the giant panda may have two subspecies, Quiling and Sichuan.

Based on the large genetic difference between the QLI [Quiling] and Sichuan populations, we hypothesized that the giant panda may have differentiated into two subspecies. Key morphometric measurements were taken from 37 adult skulls…. The results revealed very significant differences between the QLI and Sichuan populations, with 7 morphological parameters. The measurements indicate QLI giant pandas had smaller skulls than Sichuan individuals. The molecular and morphological evidence indicates that two subspecies of the giant panda have formed….

(Wan et al. 2003)

References

Bininda-Emonds ORP, Gittleman JL, and Purvis A (1999) Building large trees by combining phylogenetic information: a complete phylogeny of the extant Carnivora (Mammalia). Biological Reviews 74 pp143-175
Goldman D, Giri PR, and O’Brien SJ (1989) Molecular genetic-distance estimates among the Ursidae as indicated by one- and two-dimensional protein electrophoresis. Evolution 43(2) pp282-295
Hashimoto T, Otaka E, Adachi J, Muzuta K, and Hasegawa M (1993) The giant panda is close to a bear, judge by α- and β-hemoglobin sequences. Journal of Molecular Evolution 36:282-289
Mayr E (1986) Uncertainty in science: is the giant panda a bear or a raccoon? Nature 323 pp769-771
O’Brien SJ, Nash WG, Wildt DE, Bush ME, and Benveniste RE (1985) A molecular solution to the riddle of the giant panda’s phylogeny. Nature 317 pp140-144
Schaller GB, Jinchu H, Wenshi P, and Jing Z (1985) The Giant Pandas of Wolong. The University of Chicago Press.
Wan QH, Fang SG, Wu H, and Fujihara T (2003) Genetic differentiation and subspecies development of the giant panda as revealed by DNA fingerprinting. Electrophoresis 24 pp1353-1259
Wayne RK, Benveniste RE, Janczewski DN, and O’Brien SJ (1989) Molecular and biochemical evolution of the Carnivora. in Carnivore Behavior, Ecology, and Evolution. ed. Gittleman JL. Cornell University Press

27 Comments

PZ Myers · 14 May 2004

I just wanted to gloat and say yes, I knew all that.

Nick · 14 May 2004

Yes, but why are they so much *cuter* than other bears?

Reed A. Cartwright · 14 May 2004

Yes, but why are they so much *cuter* than other bears?
— Nick

It's the communism.

Andy Groves · 14 May 2004

Nick writ:

Yes, but why are they so much *cuter* than other bears?

And why do they taste so much better too? (For more yummy ideas, see http://www.petsorfood.com)

dana · 14 May 2004

wow. go figure. it's amazing what will still get taught in public schools and in publications aimed at kids even when the information's outdated.

that's all right--china themselves still teach that you can see the great wall of china from orbit. and, well, you can't.

Tom Curtis · 14 May 2004

Having voted that Giant Panda's are bears, I still think it was a close run thing. There is no doubt that Giant Panda's are more closely related to bears than to any other surviving animals, they are still ecologically quite dissimilar to other bears. Bears tend to be generalist omnivores, whereas Giant Pandas are specialist herbivores. I did not think this distinction sufficient to tip the balance, but it could have. Thus while Giant Panda's are bears, tetrapods are not fish, birds are not dinosaurs, and humans are not apes. In each case specialist adaptions make so great a difference in ecology that a classification system that does not make the distinction is less than useful.

Tom Curtis

Andrea Bottaro · 14 May 2004

And why do they taste so much better too? (For more yummy ideas, see http://www.petsorfood.com)

Hey, they carry dodo bird as well! Now I know what to serve next Thanksgiving to impress the in-laws!

Virge · 14 May 2004

Time for a survey question.

Should public school biology teachers teach the scientific evidence for and against Pandabearism or teach only the scientific evidence for it?

Dr.GH · 14 May 2004

I would welcome Tom to the select few that voted for bearhood, but why in the world would such a perseptive fellow say that humans are not apes?

Reed A. Cartwright · 14 May 2004

Thus while Giant Panda's are bears, tetrapods are not fish, birds are not dinosaurs, and humans are not apes.
— Tom Curtis

Actually humans are apes and birds are dinosaurs. I know of very few modern classifications systems that say otherwise.

Ben · 15 May 2004

Yep. It's the koala bears which aren't actually "bears".

Andrew · 15 May 2004

I don't believe the Chicago Cubs qualify either.

DS · 15 May 2004

The trick is to vote both ways, so as to be able to accurately point out down the road that you cast your vote for the winner.

Richard · 15 May 2004

To quote Darwin out of context, what we have here is 'something like a bear'. Going simply by the diagram, whether it's actually a bear or not is determined by where you choose to draw the 'bear-line'. It's the old lumper/splitter argument.

If the giant panda is a bear, it is, like its famous thumb, out on a limb.

God Fearing Atheist · 15 May 2004

Thus while Giant Panda's are bears, tetrapods are not fish, birds are not dinosaurs, and humans are not apes. In each case specialist adaptions make so great a difference in ecology that a classification system that does not make the distinction is less than useful.

This, folks, is just one more example of why grades and other paraphyletic groups are unnatural and meaningless. Only monophyletic groups avoid emphasis on characters which individuals (Tom, in this instance) find particularly significant. It is entirely arbitrary, of course, and far from being "useful", is downright confusing vis-a-vis phylogeny.

Tom Curtis · 15 May 2004

Dr Gary Hurd wrote:

I would welcome Tom to the select few that voted for bearhood, but why in the world would such a perseptive fellow say that humans are not apes?

A classification system is a product of human minds, not of nature. Its purpose is to quickly convey a large parcel of facts, and so its usefullness (not accuracy) depends on how many, and how usefull are the facts it conveys. Classification systems can also be inaccurate to the extent that they suggest "facts" which aren't. In biology, making descent the sole determinant of classification is equivalent to treating phylogeny as the only interesting fact in biology. But clearly that is not the case. It is true that nothing in biology makes sense except in the light of evolution; but not true that there is nothing in biology except evolution. Some adaptions are so significant in relation to an animals mode of life that we ought not to classify their possessors with their closest relatives. Obviously tetrapody makes such a difference in life style that classifying tetrapods as fish would amount to misinformation. Likewise, warm-bloodedness, hair and mammary glands make so great a difference in life style that classifying mammals as reptiles would be bizzare. In like manner, flight makes such a large difference in life style that it is, in my opinion, inappropriate to classify birds as dinosaurs. In one instance, the extreme variety, complexity and extent of avian mating signals is partly a function of the ease with which they can escape predators, compared to mammals, reptiles or dinosaurs. More difficult to argue is that humans are not apes. Phylogenetically, anatomically, and in many respects behaviourally we are apes. But our distinctive, adaptive features - language and flexible tool use specifically - make so great a difference in our mode of life that I think that calling us apes misinforms more than it informs. Language and tool use make a greater difference to our mode of life than wings do for birds, or legs did for tetrapods. I think my points are very arguable, particularly to the extent that the differences between humans and the great apes are biological differences, and hence should be reflected in a biological classification scheme. But I think the case should be argued, and I certainly don't think the fact that we are closer relatives to chimps than are the gorillas settles the issue. Tom Curtis

Tom Curtis · 15 May 2004

God Fearing Atheist wrote:

This, folks, is just one more example of why grades and other paraphyletic groups are unnatural and meaningless. Only monophyletic groups avoid emphasis on characters which individuals (Tom, in this instance) find particularly significant. It is entirely arbitrary, of course, and far from being "useful", is downright confusing vis-a-vis phylogeny.

It is only downright confusing vis-a-vis phylogeny if you think phylogenetic facts are the only facts our classification should represent. From my perspective, however, there is not reason why we should not work with two (or more) classification systems. Cladistic classifications based on enduring features, ie, amniota, diapsida, etc. are very usefull and complementary to traditional biological classifications. When traditional classifications are based on one distinctive feature (eg. monotremata; ornithischia) they may even co-incide with a cladistic classification. But unless phylogenetic facts are the only important facts in biology, there is no reason those other facts should not continue to be recognised in a classification system. Nor is this arbitrary. The fact that birds typically fly is not arbitrary, and is just as much a fact of nature as the fact that they are descendants of feathered theropods. It does make a vast difference their ecological constraints, and hence to the balance of selection they face. No feathered dinosaur would ever have developed the display of the peacock. The relative ease of flight (pun intended) makes to great a difference. Even for flightless birds, the prior possession of flight is important for understanding their geographical distribution. Of course, if GFA is really commited to phylogenetic classification only, then perhaps he can lay out his reasons for classifying humans as fish? Tom Curtis

God Fearing Atheist · 15 May 2004

I've already gone over what I think are the serious problems with para/polyphyletic groups in my rant/exchange with John a few weeks ago, and dont desire to get into it again (feel free to look it up, though). However, Tom seems confused about what I meant above when he says:

Nor is this arbitrary. The fact that birds typically fly is not arbitrary, and is just as much a fact of nature as the fact that they are descendants of feathered theropods

It is not the fact that birds fly that im calling arbitrary: what is arbitrary is your decision that this particular apomorphy is worthy of taxonomic consideration. There is, of course, no objective reason for excluding Aves from the Dinosauria on the basis of possing powered flight than there is any other character(s). It can only be, as I said above, because some particular systematist considers it significant (as Tom obviously does). The practice of naming only monophyletic groups, as the vast majority of modern systematists do these days, severs taxonomy from this sort of arbitrariness by equating them with monophyletic lineages -- groups that dont depend on my thinking they are momentous or neat. (I am not, by the way, against defining *clades* with apomorphies)

Of course, if GFA is really commited to phylogenetic classification only, then perhaps he can lay out his reasons for classifying humans as fish?

Im not aware of any phylogenetic definition of "fish," (and would be against it if there were) so I would not label humans as such. Despite my firm commitment to both phylogenetic taxonomy and nomenclature, of course. :)

Tom Curtis · 16 May 2004

GFA wrote:

I've already gone over what I think are the serious problems with para/polyphyletic groups in my rant/exchange with John a few weeks ago, and dont desire to get into it again (feel free to look it up, though).

Certainly. Where might I find this exchange?

It is not the fact that birds fly that im calling arbitrary: what is arbitrary is your decision that this particular apomorphy is worthy of taxonomic consideration. There is, of course, no objective reason for excluding Aves from the Dinosauria on the basis of possing powered flight than there is any other character(s). It can only be, as I said above, because some particular systematist considers it significant (as Tom obviously does). The practice of naming only monophyletic groups, as the vast majority of modern systematists do these days, severs taxonomy from this sort of arbitrariness by equating them with monophyletic lineages --- groups that dont depend on my thinking they are momentous or neat.

A rifle birds mating dance is beautifull, dramatic, and amusing. If on that basis I decided that rifle birds should be given a classification of equal rank to Aves, my classification would be arbitrary. Humans, possibly uniquely amongst all terrestial animals, are capable of moral considerations; and consequently deserve greater moral consideration than other animals. Classifying them in a distinct group from all other animals on this basis would be biologically arbitrary. The reason these would be arbitrary classifications is that these are not biological facts, and so have no weight in a biological classification. Knowing that humans are moral beings tells us virtually nothing about their biology, and still less do we learn about biology from knowing that we consider the mating dance of rifle birds to be beautiful, dramatic and amusing. In contrast, knowing that birds typically have powered flight, and that they all had ancestors with powered flight tells us a significant amount about biology. Arguably, it tells us more than we learn from the fact that any clade including all dinosaurs includes all birds. In this it contrasts with the fact that all modern birds have a pygostyle, which is equally an apomorphy of (modern) birds; but not an equal apomorphy with powered flight. The possession of powered flight makes a far greater difference to how birds solve the problem of ensuring future generations than does the pygostyle. This is a biological fact. Consequently, a classification that divides dinosaurs and birds into taxa of equal rank is not arbitrary. It may not be usefull, but that needs to be argued. It seems to me that GFA thinks I missed his point only because he refuses to engage with mine. Tom Curtis

God Fearing Atheist · 16 May 2004

Tom said:

Certainly. Where might I find this exchange?

Here.

A rifle birds mating dance is beautifull, dramatic, and amusing. If on that basis I decided that rifle birds should be given a classification of equal rank to Aves, my classification would be arbitrary. Humans, possibly uniquely amongst all terrestial animals, are capable of moral considerations; and consequently deserve greater moral consideration than other animals. Classifying them in a distinct group from all other animals on this basis would be biologically arbitrary. The reason these would be arbitrary classifications is that these are not biological facts, and so have no weight in a biological classification. Knowing that humans are moral beings tells us virtually nothing about their biology, and still less do we learn about biology from knowing that we consider the mating dance of rifle birds to be beautiful, dramatic and amusing.

This makes no sense to me Tom. Rifle-birds engage in mating dances. This is as much a biological fact as "birds fly or are secondarily cursorial." Humans engage in sorts of reciprocal behaviors we call moral. This is a biological fact as well. Both are very interesting and are related to lots of other interesting, biological things. Below you say that:

The possession of powered flight makes a far greater difference to how birds solve the problem of ensuring future generations than does the pygostyle.

Although im sure you cannot quantify this, surely sexual selection is an important factor in ensuring future rifle-bird generations! Therefore, I think its wrong to call some Passeriforms birds. Therefore, humans are not hominids. I think the return of dolphins to the sea is extremely significant. Therefore, they are not mammals. You say that they are "not an equal apomorphy," but have not quantified this. What is an "equal apomorphy"? How is the significance of an apomorphy measured? How significant does it have to be to exclude the group possessing it from one or all of its parent groups? Why that significant? This still seems inescapably subjective to me, but im open to be proven wrong. I'd like to say again that im not against defining monophyletic groups on the basis of particular apomorphies. Indeed, Gauthier (along with de Queiroz) has recently redefined his Avialae to refer to the clade stemming from the first form with feathered arms capable of powered flight, homologous with that in crown birds. This is exactly the sort of group Tom seems to be calling for. There is potentially a great deal of utility in that clade, i'll agree. But where is the added utility of *removing it from the Dinosauria*? To me, it would seem like my powered-flight clade is identical to Tom's, with the exception that mine does not distort dinosaurian phylogeny.

rone · 16 May 2004

Mmmm, Sichuan panda.

Tom Curtis · 17 May 2004

I found your discussion with John interesting. He expressed some of my points better, and more knowledgably than I could. There is, however, at least one point on which he and I differ. He and I agree that classifications are tools to aid research and teaching, ie, that there purpose is to quickly convey a large body of facts and expectations about the objects classified. Consequently, one measure of the adequacy of a system of classification is its usefullness to those who use it. Where we may differ is that I think it likely that having two classification schemes could be usefull. Because of this, and because it would be confusing to have the same name appear in both classification (except for generic and specific names), I think cladistic classifications should be named for apomorphies. You might then argue that the terms "dinosaur" and "bird" are now obsolete, but you would not then argue that birds are dinosaurs. In fact, we can extend this point by disambiguating. We can distinguish between dinosaurs, the group of animals distinguished in a "traditional" classification; which we can call "L-dinosaurs", and the least clade which includes all L-dinosaurs, which we can call "C-dinosaurs". We ought to agree that birds are not L-dinosaurs, but that they are C-dinosaurs. This makes clear that the dispute is about which classification system is more convenient. It is not about which classification system is natural or arbitrary. It is true that a clade is a natural grouping (for some sense of the word natural); but so is the category of creatures that live and breed exclusively in water. That category includes fish, whales and lobsters, and though it is natural, it is not usefull. This brings me to your comments:

This makes no sense to me Tom. Rifle-birds engage in mating dances. This is as much a biological fact as "birds fly or are secondarily cursorial." Humans engage in sorts of reciprocal behaviors we call moral. This is a biological fact as well.

Rifle-birds and bower birds both engage in mating dances, and both are natural behaviour. Where I to insist on classifying bower birds with whooping cranes because I consider their dances absurd, but classify rifle birds with royal albatross because I consider their mating dances beautiful, I would be arbitrary. What I consider beautifull may be a biological fact, but it is not a fact about the biology of birds. In contrast, flight is a fact about the biology of birds, and a very important one. A biologist interested in migratory animals would probably notice that bird migrations tend to be longer than mammal migrations. If she sought to explain this, she would probably make reference to the birds possession of flight as a significant factor. She might also notice that where mammals frequently hibernate, birds never do. Again she would probably make reference to flight in birds as part of an explanation of this. Another scientist, interested in biogeography might notice that the number of bird species on isolated islands far excedes the number of mammal species. Again, flight is likely to be mentioned to explain this. A third biologist, interested in sexual selection, is likely to notice that bird's display patterns are far more brilliant, and likely to attract attention than are the display patterns of mammals. She is also likely to notice that mammal displays, when bright, are easily concealed, far more so than is the case with birds. Again, flight is likely to get a mention in explanations of this fact. In contrast to flight, the fact that modern birds do not possess teeth is not likely to be frequently mentioned in explanations of birds behaviour and life styles. The frequency with which flight factors in explanations of bird behaviour, or that language factors in explanations of human behaviour mean that these are not just one more apomorphy amongst others. They have an unusual significance. This significance is brought out by looking back to the ancestral group. Birds are descended from dinosaurs. Does that mean we can learn a lot about probable dinosaur migrations, or sexual display by looking at birds? I find that highly dubious; indeed, we would probably learn more by looking at mammals. Read as anything more than a statement about ancestry, saying that birds are dinosaurs is misleading. Consequently, insisting that biologists use a classification system that says that is equivalent to insisting that discovering ancestral relations is the only significant function of biology. But that just ain't so. Tom Curtis

God Fearing Atheist · 17 May 2004

When you say, Tom, that it would be absurd to erect polyphyletic groups on the basis of mating behaviors, I fully agree. The issue though was not the creation of polyphyletic groups, but of paraphyletic ones. Aside from the odd pheneticist, perhaps, im sure everyone would agree.

Although you continue to insist that flight is such a significant apomorphy that birds should be excluded from the Dinosauria, you did not quantify this as I requested. You say that flight is an important aspect of lots of interesting things about avian biology and ecology, and I agree. However, there are lots of other apormophies that are significant in their own way, and until you can 1) explicltly tell us how you are determining this significance, 2) explicitly tell us how significant an apormophy must be to exclude the clade possessing it from its parent group, and 3) justify that line in a non-arbitrary way, these divisions you are drawing are going to continue to exist in your mind only.

Additionally, Im still not at all sure how my monophyletic flight-clade, nested in a monophyletic Dinosauria, is any less useful for the purposes you propose. As I said last time, they appear to be identical: you propose a monophyletic flight clade, I propose a monophyletic flight clade. The only difference is that you want to elevate it to the same "rank" as Dinosauria, the purpose of which (so far as I can see) is to satisfy your whimsical, subjective opinion that flight is really significant somehow, and consequently giving people a caracature of dinosaur phylogeny.

Like much older defenses of paraphyly in taxonomy (older because, really, this is a dead/dying position) Tom seems to be saying that there is something fundamentally wrong about a world that does not acknowledge dinosaurs as equal to birds, prokaryotes as equal to eukaryotes and so forth. The reasons, in all of these cases, all seem to boil down to "because I say/think so."

Dont get me wrong Tom, you're free to believe whatever you want about anything. My problem is trying to pass these opinions of yours off as useful and objective. Neither my fancy nor your own, Tom, has any place in science.

Pete Dunkelberg · 19 May 2004

My goodness Tom, are you still saying that birds are not dinosaurs? And your main reason is that they fly? What about bats? They fly. Does this make them not mammals? Are they birds then? Whales live in the sea. Are they then not mammals? And moles. They live in the ground. What self respecting mammal would do that? You conclude:

Read as anything more than a statement about ancestry, saying that birds are dinosaurs is misleading. Consequently, insisting that biologists use a classification system that says that is equivalent to insisting that discovering ancestral relations is the only significant function of biology.

I don't want to dwell on the non sequitur, but I think there are problems with the first statement. First, saying that birds are dinosaurs is supposed to be a statement about ancestry. Second, it is not misleading at all. The more familiar you become with small theropod dinosaurs, the more natural it becomes to think of birds as dinosaurs. A large part of the reason that some people don't like to think of birds as dinosaurs is that dinosaurs have a very unbirdlike image in some people's minds. Surprise! Dinosaurs, or at least the experts' understanding of them, have changed a lot since you were a kid. In his book _Dinosaurs of the Air_, Greg Paul spends a lot of time trying to draw a non-arbitrary line where birds start. He can't. And it has only grown harder to draw such a line since that book was written. The number of feathered dinosaur fossils continues to increase. Unless you propose that feathers evolved several times independently, the common ancestor of these dinosaurs had feathers, and so did other descendants of that ancestor for which the integument is not known directly. And various dinosaurs flew. Oh and by the way, it's no good denying you're an ape. Once you admit it, to yourself first of all, and them come out as an ape, you'll feel much better. :)

britt · 12 October 2004

you start to talk about the panda's niche but then stop alltogether. you should not do that. its confusing and not very detailed at all!bad bad bad!

jojo swervy · 12 October 2004

This website is sooooo boring, you should take it off the web. I had to do a project on the red panda! Not the giant panda. As far as im concerned it was a waste of my time and i hope the maker of this site is banned from posting information like this crap on the web for young childeren to see! You get too carried away bout your stupid giant pandas like stop talking about them!!! anyways I think that you get way off topic and that this site should not be allowed to be on the web. I hope that this comment teaches you a lesson and next time you go to put this crap on here, make it about red pandas like it said it would be about. Don't go blabbing your head off about these stupid giant pandas when all we want is to know about the red pandas. When you put a site on the web like this, make sure that you put it under the giant panda section instead of the red panda section.

Anton Mates · 12 October 2004

Speaking of niches, I'm moderately surprised that Tom Curtis would consider "bears" to form a meaningful ecological category...with or without the giant panda. Polar bears are Arctic marine top predators; spectacled bears are arboreal cloud forest inhabitants which eat mainly fruit; sloth bears are grassland/dry forest inhabitants specializing on ants and termites. Why should giant pandas (which very occasionally scavenge meat, incidentally) be considered the odd one out from an ecological point of view?

That's not a rhetorical question...if Tom (or any passing bear expert)'s still checking this thread, I'd be interested to know if there are lifestyle characteristics and selection pressures which are common to all bears but not to, say, other Carnivora or mammals in general.