Giant Pandas (ailuropoda melanoleuca) confound me. I think they confound Mother Nature, too.
It's mostly about their diet. Not bamboo, but bamboo shoots. There's a very specific part of the bamboo plant's lifespan where it is mostly starch and protein. You might have had some, it's popular as an ingredient in noodle dishes. Here's the thing: they're only available five months out of the year. After mid-August, most pandas subsist on bamboo leaves, which does basically fuck-all nutritionally speaking. Moreover, every single bamboo shoot grows at roughly the same pace, which means a group of pandas need to find two different species of bamboo in their range or starve to death.
It's not like they have to eat bamboo: pandas can eat fish, honey, small game animals - but they choose bamboo shoots in defiance of their own bodies. They literally are not born with the capacity to ingest bamboo! Their bodies remain carnivorous! They do not possess the gut flora necessary to process bamboo from birth! They have to eat fecal matter from their mother in order to develop such a colony on their own!
It gets worse: bamboo contains cyanide! I do not exaggerate when I say that if the average panda is allowed to eat their fill, they will ingest enough cyanide in one day to kill twenty adult humans. Significant amounts of work done by their digestive system is dedicated to keeping these ridiculous beasts from poisoning themselves.
As a secondary note, keeping a giant panda in captivity is an enormously expensive project. Not just because they are huge moody ursids that want to eat thirty-odd pounds of bamboo shoots every day, but because the CCP (yes, China) charges a panda's hosting nation $1,000,000 a year to lease them in 10-year periods, with the understanding that any cubs born are Chinese state property. What the state did with all that money was unclear, but back in 1998 the WWF (World Wide Fund for Nature, not McMahon's flying circus) had to sue the Chinese government to make sure that at least half of that money went to actual conservation efforts.
Just...why, giant pandas? I can understand finding an ecological niche, penguins are my favorite animal and their only defensive measure against predation is literally "move to another state until junior can swim", but penguins at least have bodies and minds that are largely in agreement! Fish is good, fish is tasty, lots of fish = healthy penguin. Even under ideal ecological conditions, pandas are wired to handicap themselves. The only other animal I know of with this capacity for self-sabotage is typing out this post.