Why don't animals eat their own kind

Feces consumption in the animal kingdom: This is why animals like to eat their own feces so much

Updated

Consuming feces is a disgusting proposition from a human point of view. In the animal kingdom, however, that makes perfect sense.

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Normally, what comes out at the back shouldn't come back in at the front. But some animals do not adhere to it: They eat excrement - some their own, others that of their own kind, and still others that of other animals. Experts call this coprophagia.

What is a disgusting idea for most people (see box) is quite natural in the animal kingdom - and makes sense.

Own manure ensures survival

Rabbits, hares, rodents and some species of monkeys are so-called autocoprophages. They take care of their own excretions and those of their fellow species in order to prevent nutrient deficiencies.

Because in herbivores, nutrients are already absorbed in the small intestine. However, some proteins that are vital for the animals are only formed in the subsequent appendix and then excreted.

So that these are not lost unused, the autocoprophages once again attack their feces after digesting. So you can still enjoy the essential proteins.

The excretions of others

Dung beetles, roundworms and numerous species of mites belong to the group of allocoprophages. They feed on the excrement of other animal species.

In doing so, they target the organic substances that are still contained in the manure. This makes them an important element in the ecological cycle of materials.

Eat feces for the great love

Another group of animals, to which the Egyptian vulture belongs, pursue another and completely different goal by eating excrement: They are trying to find a partner.

Female Egyptian vultures prefer males with bright yellow faces, possibly because this indicates a strong immune system. The pigment lutein is responsible for the yellow coloration.

Since this is only partially available in the carrion, the actual source of food for the animals, the males also use the lutein-rich faeces of ungulates such as cattle, sheep and goats.

Humans also consume feces

Not only do animals eat feces, but some people too. In contrast to animals, however, it is not a natural behavior in these. Rather, it can be traced back to a disorder in the brain - specifically to a damaged amygdala, which is important in healthy people for the emotional evaluation of situations and the analysis of possible dangers.

If this central part of the brain is defective, the feeling of disgust is switched off, among other things. And those affected are not afraid to eat their own feces, as researchers from the Mayo Clinic in Rochester, USA, reported in the Journal of Neurology in 2016. Accordingly, dementia and brain tumors are considered to be the triggers of coprophagia in humans.

Coprophagia in the subjects examined for the study was often accompanied by smeared stool, aggressive behavior, sexual hyperactivity or the desire to swallow any kind of object.