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Anonymous
a friend of mine was talking about bears and dogs,apparently they have the capacity to make thier own vitamins (internally) is this true?
>> Anonymous
utorrent>azureus
>> Anonymous
Primates can't synthesize vitamin C because the gene that codes for that function got broken in our common ancestor (we still have the gene but it doesn't work). Most other animals can make vitamin C, except guinea pigs who also have the gene broken (though in a different way than primates as one might expect).

I'm not sure about other vitamins. I think humans can produce at least D internally.
>> Anonymous
Cats can't produce some amino acids internally if they don't eat meat. That's why putting a cat on a vegetarian diet is a bad, horrible idea.

Dunno about other animals. It'd stand to reason that some birds' skin, for instance, wouldn't produce vitamin D3 like a humans' would in response to UV radiation from the sun. But really, no idea for reals.
>> Anonymous
>>112594
The production of vitamin D in humans is promoted by exposure to sunlight. Those who live in areas of low exposure must make up for it with diet.
>> Anonymous
Dogs can produce Vitamin C. I know this because I remember learning about how during the Amundsen expedition to the South Pole they had to eat some of their sled dogs to prevent getting scurvy.
>> Anonymous
>>113246
Nah, most animals' livers contain piles of vitamin C. It's how many siberian reindeer-herding tribes get theirs. Doesn't mean that a dog can produce it independently (though I wouldn't be surprised if they could).
>> Anonymous
makes sense if a bear can since they hibernate for a good chunk of the year.
they cant get vitamins from a diet if theyre asleep.
its logical to say they adapted to just making their own instead of facing the frigid weather.

as for dogs, not too sure. i dont think they are very closely related