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Cake day: July 4th, 2023

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  • That’s the speculation on gut length in pandas based on statistical methods but panda teeth are already well adapted to eat bamboo so selection has been working on them for some time or at least there is no opposing selection at work in panda teeth preventing them from changing. Strangly the large canines are used to cut the bamboo which might be what created their niche in the first place, but their teeth are otherwise very different from other bear teeth.

    Its been a while since I dove into this but from what I remember the speculation with gut length has to do with metabolic tradeoff. If pandas don’t get that tradeoff with the food they eat then they’ll probably keep their current gut length. Or they might make a different tradeoff (slower peristalsis, more gut surface area)


  • Idk if “descendants of omnivores” counts because then you could exclude a number of critters like pigs for being “descendants of herbivores” and then 'why do pigs have more stereoscopic vision than a t-rex ’

    The obvious caveat is that pandas at the minimum don’t have selective pressure for side eyes or they have something pressuring stereoscopic vision even more similar to how aquatic animals have less selective pressure for forward facing eyes.

    I would imagine the way pandas eat bamboo stalks is more visual than most herbivores and that alone could help them retain steroscopic vision.




  • If a squirrel falls they’re probably not going to squish as hard as a monkey. Lots of scavengers also have forward facing eyes (ex racoons) and pandas notably have forward facing eyes and are herbivorous.

    I think the climbing and jumping theory is better than the predator theory on account that it explains why large aquatic animals aren’t selected for close frontal eyes.

    Plus many predators (cats notably) do climb and jump. Humans and monkeys also have werd postures that might lead to them falling over easier.

    In reality its probably never just one pressure that leads to these kind of evolutions.


  • Convergent evolution has more to do with environment and trophic structure than it has to do with lineage. Any animal that can produce a complex eye can have similar evolutionary pressure given similar environments unless there’s some other stronger pressure.

    Animals low to the ground or water often have slitted eyes (including goats who spend a of time with their heads down)



  • Fedizen@lemmy.worldtoScience Memes@mander.xyzOnLy tWo eLemEnTs
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    19 days ago

    Well I think we should caveat this as “in humans there is a tendency for sex to fall under two large umbrellas of typical characteristics” as there’s millions of small caveats for many mammals (its speculated parthenogenesis could naturally occur in humans under certain conditions).

    Because of how early some features tend to develop in mammals there’s less variation than in other types of animals.

    Outside mammals: Amphibians, Reptiles and Birds have many species that can change sex.

    Outside animals: Plants and fungi are an absolute mess.






  • Fedizen@lemmy.worldtoScience Memes@mander.xyzFeynman rules
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    30 days ago

    From what I’ve seen Feyman was more than a little pedantic and he liked to emphasize that science doesn’t answer “why” it answers “how”. So if ICP asked that question Feyman would say “take an undergrad physics course because its not easy to explain in a soundbite”