Why is a cow's digestive system is not like a human's digestive system?

Answer 1

Cows are ruminants, whereas humans are monogastrics. That means cows or cattle have a stomach with four compartments and an ability to regurgitate partly digested matter back up to rechew while they are resting. Cows are also true herbivores, which means they rely on plants, being primarily grass, to sustain themselves. Humans, on the other hand, only have a simple stomach with one chamber and are omnivores, or eat both meat and plants. Because humans are omnivorous by nature we do not need a complex stomach to fully utilize and digest the 99% plant-based diet to turn it into energy, protein and other nutrients for the body's maintenance, reproductive and metabolic needs. Cows, on the other hand, do.

Grass is considered a coarse plant material, though it has nothing on woody plants like trees and shrubs, compared to the more tender plant material like lettuce and spinach, as well as fruit and nuts which are easy for a human to digest and can be utilized as an energy source. Grass, on the other hand, will simply pass right through a human's digestive system because we lack not only the complexity in the stomach area, but the enzymes and microbes to aid in the digestion of this plant. Cows have both of these things which make them one of much more efficient at consuming and digesting such plants than humans.

So why is a cow's digestive system not like a human's? 1) Cows are herbivores that eat grass, humans are omnivores which tend to not eat grass, but mostly softer plants like lettuce, as well as fruits, nuts and meat. 2) Cows are much more adapted to a life of eating grass and legumes than humans are or will ever be; 3) Cows are an entirely different species from humans; cows belong to the family Bovidae, humans belong to the family of Apes.