Why do monkeys kill their young
Scientists have long noticed that male chimpanzees are prone to infanticide. For many years, all sorts of assumptions have been made about the nature of this phenomenon, but it was possible to come to a single point of view only recently. After analyzing the materials accumulated over 24 years of observations of primates, zoologists finally found the answer to this question.
There were four hypotheses explaining the killing of other people's cubs by male chimpanzees. The first is related to the rivalry between males. It was believed that the offspring of other males were exterminated in order to get rid of future competition for females. The second suggests that it's all about the struggle for resources. Chimpanzees often suffer from a lack of food and in this way remove excess mouths.
The third considers the option that adult males see food in the cubs. Chimpanzees are known to be omnivorous and often prey on smaller primates. Colobus monkeys suffer the most in this case. Especially often their defenseless and not too mobile babies become prey.
Well, the fourth one, which turned out to be correct, speaks about the peculiarities of the reproductive cycle in female chimpanzees. They feed the cubs for a long time, sometimes 4-5 years. All this time, the females do not ovulate and they do not allow males to mate with them.
Zoologists have come to the conclusion that chimpanzees kill small brothers so that their mothers become more capable of mating faster. Scientists from the UK, Switzerland and Uganda were dealing with the problem. They spent 24 years observing a community of chimpanzees in the Budongo Nature Reserve in western Uganda. There are 60 animals that live there, which are kept in one pack.
During the observations, male chimpanzees attacked the cubs 33 times and in 30 cases they managed to kill them. It may seem that for almost a quarter of a century, the figure is not impressive. But it should be remembered that this type of monkey reproduces very slowly. In total, 103 babies were born in the pack over the years of observation. This means that 23 percent of those born died due to the fault of relatives. This is 63 percent of the total number of deaths during this time.
At the same time, having considered the sexual composition of the group of killers, scientists were surprised to notice that females sometimes do this. In 12 cases, the cubs were attacked by males, and in 5 — by females. In other fatal situations, the gender could not be determined. It also turned out that males die more often at the hands of relatives. There were only 7 females for 19 males. Almost always, small chimpanzees became victims at a very young age, up to six months. It was also noticed that in 6 cases the beating of infants was accompanied by their eating.
The fact that small males die more often should confirm the hypothesis of competition. But this is not the case. The thing is that zoologists could not determine the ratio of cubs of different sexes in the community. Perhaps it's just that more boys are being born. Therefore, they are more often deprived of life.
Chimpanzees in general often throw riddles to the scientific world. For example, it took a long time in academic circles to figure out why these monkeys like to throw their feces.