American author Bill Schutter's biology popular science book "Cannibalism" published in 2020 attracted my attention with only a short title, reminding me of today's highly competitive contemporary society, and the inner volume has become a popular word in recent years. But after reading the book, I found that this book is about a special way of eating in the process of biological evolution: the competition of using the body of the same kind as food seems to be more fierce, but behind it has a very significant evolutionary significance. So the author defines "cannibalism" as the behavior of one individual in a species consuming all or part of the body of another individual in the same species.
This book interprets the evolution of biological civilization in nature from the fields of anthropology, sociology, medicine, biology, religion and so on. What we previously thought of as bloody cannibalism between animals concludes in this book that cannibalism in the biological world is not an anomaly at all, but a normal response to various environmental factors. In the second half of the book, the author begins his narrative from the animal kingdom to humans, exploring the causes of cannibalism and cultural taboos.
In the animal kingdom, cannibalism includes sibling rivalry, parent-child cannibalism, sexual cannibalism, stress cannibalism, expendative offspring, and scavenging; in humans, it is embodied in ritual behavior, medical treatment, and mental disorders.
Sibling rivalry and cannibalism are relatively easy to understand and common types, such as the sowing spawning of fish, only a small part of the eggs will be fertilized, and the remaining eggs will become food; the stressful cannibalism is caused by the lack of food or space and other resources, the most common is the phenomenon of "big fish eating small fish" between fish.
The sex-eating counterpart is one of the more interesting types, and spiders are one of the representatives. For red-backed spiders, it's the female choosing the male that's suitable for mating. Some studies have found that smaller males, i.e., who are not usually very healthy, are often eaten by their own kind (females and males). After the end of male and female mating, the female spider may eat the male, which is beneficial to the male: this behavior will reduce the female's acceptance of the later suitor; on the other hand, the male who is eaten will have a longer mating time than the uneaten male, and the number of offspring will be more, and the male will be eaten to make the female get more nutrition, so that the offspring have more reproductive opportunities, so that the male genes will be inherited. When there are more males, females also choose to eat some of them as their food source before mating, and the authors comment, "When the number of short-lived male spiders is relatively small and the likelihood of encountering fertile females is low, cannibalism after mating seems to have good evolutionary significance." In these cases, when meeting a potential partner, being able to give everything means it's worth paying--- even if it means giving your life. "Maybe this is the charm of evolution, for a single organism, passing on its genes is a mission, and the evolution of living things has never stopped, and it will never reach the peak of perfection."
Expendable offspring manifests itself in breastfeeding (which is known to be extremely draining on the mother's body) and mothers raising offspring with organs or all of their tissues. The black lace spider has an extremely special way of raising offspring spiders, when the spider mother can not afford the nutrients required by the spider offspring, it will call on the toddler to gather and climb on its body by tapping the spider web, and then eat it raw, they will suck all the tissue liquid in the body of the large spider as their own nutrients, and finally only an empty shell is left. For the cultivation of biological offspring, matrilineal investment and patrilineal investment are not uncommon, although bloody, but touching and beautiful.
The author says, "In the animal kingdom, as far as cannibalism is concerned, there is no gray area, no sin to speak of, and no deception. Faced with a series of environmental changes--- whether there are too many children, too few spaces, too few males or a scarcity of food, all the animals do is a variety of coping methods--- occasionally bloody, always charming. It was only at this evolutionary branch of our own that the diarrhoea and uncertainty surfaced, and it was here that I found that 'cannibalism' was painted with an equal amount of scarlet and gray shades. ”
In the second half of the book, the phenomenon of cannibalism is mentioned. Some anthropologists have pointed out that certain human groups engage in cannibalism in order to speed up the separation of the souls and bodies of the dead, which is equivalent to a Christian funeral or last-of-life prayer. The emergence of Kuru disease (a disease of the central nervous system manifested by tremors, muscle twitches and impaired coordination, which eventually makes people unable to swallow, lose control of the body and eventually die) in new Guinea is associated with this cannibalism, and the latest research has found that it is not because of eating part of the body of the sick person that causes the occurrence of Kourou disease, but because in the process of cutting parts of the body, the pathogen in body fluids will pass through wounds on the skin, the human mouth, Mucosal and retrograde transmission (i.e., vaccination transmission). This kind of cannibalism, which is related to religious etiquette, has been greatly reduced in recent years at the request of the local government, and the incidence of disease has decreased year by year.
In addition to religious rituals, cannibalism can also occur in medical care, with the placenta being the most common form. Pregnant women will be required to eat the placenta after giving birth, the current research believes that the placenta contains a large number of hormones can reduce the occurrence of postpartum depression, on the other hand, there is a lot of nutrition in the placenta, which can supplement the physical loss of pregnant women to a certain extent. In Chinese medicine, the placenta, also known as the "Purple River Car", is a good tonic and can greatly replenish vitality. In addition, cannibalism is also a cultural taboo, and there is no shortage of depictions of man-eating demons in literary works. Cormac McCarthy described cannibalism in the science fiction novel "The Road", and vampires, zombies and other film and television works have also become popular around the world.
For animals, cannibalism has evolutionary significance. For human beings, cannibalism has become part of myths and legends, the oldest and oldest level of human life, although it has played an important role in the evolution of human beings and has also built the basis of some medical therapies, but with the development of humanities and sciences, it may not exist in the current world. This is the benefit of advances in the humanities and sciences.
The evolution of animals has never stopped, and the same is true for the evolution of humans. However, because of the emergence of civilization, the evolution of human beings and animals are necessarily different, and the evolution brought about by the progress of science and humanities is a gift from God to mankind.