In nature, why do some animals live by sucking blood, but humans cannot?

I think the main reason for this is that people can't achieve nutritional balance by sucking blood, and there are bloodborne pathogens in the blood, in addition, the main thing is that humans don't have blood-sucking tools like other blood-sucking animals, so in general, human sucking blood is harmful to human beings themselves, and besides, in many countries, blood-sucking is illegal.

Because the body functions of each life are different, the substances required are also different, just like a mosquito sucks blood for a living, and a sheep eats grass for a living.

Maybe it's not that people can't do it, but they can't do it, not only are they uncivilized, but they also base their lives on the mutilation of other lives, which is too cruel. This is the biggest difference between humans and animals.

Because the direction of biological evolution is different, and the choice of food is also different, some animals live by sucking blood, while humans cannot.

Humans have evolved to be unable to eat raw and cold food, and certainly cannot survive like vampires.

Human survival requires the participation of many elements, if it is only a single one, like a vampire sucking blood, people can only take in a small part of the energy, can not meet the needs of survival.

Because the human body needs a lot of nutrients for development, and the nutrients contained in the blood are not enough for human development.

Definitely not, because different kinds of organisms have different ways of obtaining food, and human beings cannot meet the nutritional needs of the development and normal operation of the body by sucking blood, and we do not have a strong immune system, and the blood can transmit pathogens, which can lead to a lot of diseases.

It is vampires who live on blood, we humans need a lot of nutrients to survive, and the nutrients in the blood alone cannot sustain our lives, so we are mammals, not vampires.

For natural creatures, survival is a top priority, so they will find ways to get food. Of course, different kinds of creatures get their food in different ways. Most animals get their energy and nutrients by ingesting plants or other types of animals.

There are also organisms that can survive by parasitizing, and some organisms seem to be nothing special on the surface. , but the way they get their nutrients and energy is trembling because they survive by sucking the blood of other animals. Some of your friends may think of vampires when you see this message, but this creature does not exist in reality.

There are many animals that depend on blood to survive.

Because the nutrients needed by the human body are far from enough to simply suck blood, human beings not only need trace elements and dietary fiber in vegetables, but also need the rich protein and carbohydrates contained in meat products, which are necessary factors to maintain good health.

Because humans don't need to suck blood at all, humans have mastered fire and can use it to roast food.

Because the human stomach can no longer adapt to it after tens of thousands of years of evolution, the nutrients in the blood are also very low, and it cannot be used to maintain the characteristics of life activities.

It's possible. Because extraterrestrial life may live in a very different environment from Earth, it is possible that extraterrestrial life does not need to breathe.

Whether extraterrestrial life needs to breathe or not is currently unknown. The first non-breathing animal, it was called "Cercospora salmonata" (

Oxygen is the material condition on which we humans and most of the creatures on Earth depend, and it may be replaced by something else on other planets.