So Giant Pandas were made for digesting meat, however, they found themselves in a vast habitat with no meat and were forced to eat bamboo. I understand this to some extent - but aren’t/weren’t there monkeys, fish etc (for food) in the same region of China?
However, I can’t find info on why they would reproduce semi-formed young that need highly intensive parenting (the licking of the genitalia because they can’t go to the loo by themselves is a little icky). Having no natural predators only partially explains this - wouldn’t it be easier if they came out of the womb more formed than this?
most bears birth young that are very hamster looking. the mom bear and baby bear live in the birthing den until the baby is able to walk.
most bears birth their babies during hibernation.
polar and pandas don’t have a hibernation time. polar do stay in the den for quite some time, until the wee bear can walk, living off the seal binge. pandas will leave young in the den to go out nearby for bamboo. once panda baby can walk, mama bear will stash them into trees while they go further a field for bamboo.
It is my understanding that Panda babies are the most unformed of all bear babies. Am I wrong?
Nitpick: Bears are omnivores. Black bears are mostly vegetarian (and most of their non-vegetarian diet is insects), as are grizzlies in some areas.
Well the documentary I just watched said Pandas were made for digesting meat, so have had to adapt physically and disgestively to a bamboo diet.
Bears would probably find it difficult to live off monkeys-- small, fast critters that live high in the trees aren’t that easy for big, lumbering bears to catch. But, as has already been mentioned, most bears are omnivores (polar bears live mosly off seals), so it’s not a huge step for pandas to have made. Also, pandas do eat insects and fish-- they’re not completely vegetarian. Think of them as one end of the carnivore <—> omnivore specturm. Keep in mind that this change was probbably gradual, and not the result of a population of bears suddenly finding “themselves in a vst habitat with no meat”. It’s more likely that the bears adapted to a habitat (bamboo forests) that had no inidginous bear populations. Pandas have a long evolutionary history, going back 15M years or more, so there was plenty of time to adapt to that new habitat.
Polar bears will eat berries and other vegetation, if those and no other foods are available, though they are mostly carnivorous.
Then why haven’t their digestive systems evolved well - apparently they only take a small percentage of everything they eat into their system, that’s why they have to eat continuously.
Because there has been no need. Simply eating constantly has worked well enough so far.
Bamboo isn’t very nutritious. Most mammals that get all their nutrition from grass (bamboo is a grass) spend a lot of time eating.
"(the licking of the genitalia because they can’t go to the loo by themselves is a little icky). "
I’m sure someone will correct me if I’m wrong, but I think that is a fairly common issue.
The advantage of the bamboo diet is that bamboo is available in essentially unlimited quantities pretty much all the time. (Pandas have a hard time in years when some of the bamboo flowers and then dies, but most of the time there’s plenty.) The price of this secure food supply is that they have to spend most of their time eating it. They compensate in part by eating only the most nutritious parts of the bamboo, and passing it through the digestive tract quickly.
Animals are not completely flexible in how they can evolve. There are always going to be morphological and genetic constraints on what is possible. The panda’s carnivore digestive tract has not been flexible enough to develop extensive foregut fermentation (like cows) or hindgut fermentation (like horses), so that they can’t make use of much of the cellulose in their diet (which is broken down by bacterial fermentation in either the fore or hind gut of more specialized herbivores.) Therefore they cannot simply eat a lot of grass and let it ferment inside them like cows and horses do - they have to pass it through quickly.
Like the products of evolution in general, pandas are not intelligently designed. They are cobbled together and jury-rigged. What matters is not elegance or efficiency, but what works. It worked for pandas for millions of years, until humans came along, and that’s all that mattered.
Are you postulating that evolutionary mechanisms respond to ‘need’? I was not aware that there was any force or agency of evolutionary change that from time to time assessed ‘need’ and planned the next stage of an animal’s evolution accordingly, so as to ‘respond to need’, the way that the forward planning office of a company develops new products to respond to changing patterns of consumer demand.
According to the evolutionary theory I learned about, and may have misunderstood completely, random mutation produces random variations on a theme. In some cases, the random mutation just happens to confer a survival advantage and so it spreads through the gene pool. ‘Need’ doesn’t come into it. There are many instances of animals that experience a dire need for some genetic variation, but sadly (for them) this doesn’t mean they can expect a handy evolutionary change to come down the chute. Right now, tigers would love to develop the ability to survive on grass. They may well die out altogether if they don’t. But this has no impact at all on which random genetic mutations may arise within the ‘tiger’ blueprint.
I think he means “selective pressure”. If bamboo is so abundant that a panda with a poor digestive system survives just as well as a panda with a random mutation that allows it to get more nutrition from grass, both pandas will survive/breed about equally, and no overall evolutionary change will occur. If a situation were to arise where bamboo became more scarce, the random mutant pandas would have an advantage over those that can’t digest grass as well. The panda population will experience selective pressure in favor of those better able to digest bamboo, gradually making all pandas better at it. Depending on the way you look at it, evolution here is sort of responding to “need”.
I remember learning (when I was a kid) that pandas aren’t really bears, but are a different kind of animal more closely related to raccoons. (Koala “bears” being another example of “bears” that aren’t really bears.)
Then I seem to have heard that relatively recently, scientists changed their mind and said that, yes, pandas really are bears after all.
Apparently, according to Wikipedia, the matter is still somewhat up in the air.
I don’t know how much of debate is still going on. I think that most biologists accept them as members of the *Ursidae *family. They are genetically closer to bears than to racoons, although I suppose one might make a case for putting them in their own family, seperate from true bears.
Some of the confusion comes from the two types of pandas:
Giant Pandas are placed in the bear family, while the Lesser (or Red) Panda is more closely related to racoons or skunks, or possibly it should be in its own family. At any rate, I think there is much more debate about how to classify the Red Panda than how to classify the Giant Panda. As was pointed out in another recent thread, though, there isn’t an official sanctioning body for classifying organisms at the Family level.
Koalas are only called “Koala bears” outside Australia. They’re marsupials, so they are as genetically distant from the *Ursidae *family as knagaroos are. It was once common to give Australian marsupials names that link them to the placental mammals they superficially resemble (eg, tasmanian tiger for thylacine)
Wiki is a great resource, but don’t accept everything you read there as gospel.
Both the Giant and the Red Panda have been taxonomic puzzles. Formerly they were frequently classified together in their own family (they both eat bamboo, and have similar “false thumbs” for handling it). It was debated whether they were more closely related to raccoons or to bears.
The consensus today, based on genetic and other evidence, is to put the Giant Panda in the same family as bears (Ursidae), and the Red Panda in its own family, the Ailuridae.
Actually I would guess that the probability if bamboo became scarce would be more that the panda would go extinct than that it could evolve fast enough to survive.
There appears to be a feeling in some posters here that evolution finds the optimum solution for survival. The fact appears to be that evolution merely results in the *minimum alteration that will allow survival of a species.
I thought I had read once that the giant panda originally called the “particolor bear,” and ended up getting renamed “panda” when the physiological similarities between it and the red panda were discovered? If that’s the case, they had it right the first time. Interestingly, the OED (1920 edition) does not include the panda bear in its definition of “panda,” only the red panda.
Way to clear up the confusion: stick the thing with a family name that means “cat.”
(Full disclosure: elephant shrews are neither elephants nor shrews.)