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
Others have explained it well, but another fact about many animals that we think of as herbivores(cows, deer, squirrels) will commonly eat meat if it’s available! Cows and deer have both been seen munching on baby birds in low nests, as well as chewing on bones from carcasses
Fun fact: We actually still have most of the genes required to synthesize vitamins, such as the gene to synthesize vitamin C which dogs and cats possess, but it is deactivated.
When we started living arboreal lifestyles and consuming a lot of fruit, it was no longer evolutionary preferential to synthesize our own vitamin C- it takes much less energy to absorb it from food, where the plants have already expended the energy to synthesize it- and therefore the gene has gradually grown redundant in chimps and eventually humans.
The same has occurred for many other aspects of our genes. Any expense of energy which can be avoided is generally selected against, because individuals who could survive longer with less food were more likely to survive periods of scarcity and thus produce offspring.
Because it is the most efficient. We can get all the nutrients we need in about an hour over all and spend the rest of the time doing stuff.
Carnivores spend 80% of their day sleeping, and herbivores spend 80% of their day eating. We spend 30% of our day sleeping and <10% eating. It’s the best of both worlds.
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