why do humans need to eat many different kind of foods to get their vitamins etc but large animals like cows only need grass to survive?
In: Biology
Wild deer sometimes eat dirt, well if they can they find a salt lick. But they still go looking for minerals not found in the plants they eat. They also occasionally munch baby birds. Possibly other small wildlife, but I know about the birds. It’s a bit like the way a dog or cat sometimes eats grass.
In addition to the ‘efficiently breaking down grass’ thing, and the ‘they eat a variety of plants’ thing, there’s also the fact that species typically evolve the ability to make vitamins that they can’t get easily in their diet. For example, humans make vitamin D because there aren’t many food sources of it, but we can’t make vitamin C, but can find it in food. But other species can make their own vitamin C.
It’s a trade off between needing to find a variety of food and not needing the cellular machines to make more stuff.
Ruminants like cows are able to extract more nutrients from vegetation than we are, due to their specially adapted digestive system and gut flora.
Ruminants ferment food in their four-chambered stomach over an extended period, which enables their gut bacteria to break down complex carbohydrates, proteins, fiber, which in turn synthesize their own nutrients that the host can absorb.
Additionally, ruminants will consume animal bones in order to obtain phosphate and calcium if they’re not able to obtain it elsewhere in their diet.
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