Can a dolphin kill a crocodile?

Question:

Do animals never kill a conspecific?

Answer:

Over the past decades, a number of characteristics have been discovered and described in our animal relatives that have long served to define human uniqueness: culture, complex communication, empathy and cooperation have now been demonstrated in numerous species, such as dolphins and great apes. The fact that killing conspecifics, which humans are extremely efficient at, is not one of these characteristics - this behavior is also widespread and well-known among animals.

Anyone who has once held mice as a child may share the sad experience: The number of helpless, naked newborns decreases overnight - the mother or other adult animals have eaten the offspring. One reason for this behavior is often stress due to too tight housing conditions. But cannibalism also occurs naturally in many species. In fish, amphibians and reptiles, for example, their own relatives are often part of the everyday food spectrum. In this way, some pioneer fish species can survive in temporary or newly created waters, in which (at the beginning) their own young are the only prey for the adults. Young crocodiles and monitor lizards also have to be careful of adult conspecifics as well as of alien predators. For male praying mantises and spiders, the partner is often the last sight in life - after mating, the smaller males serve the females as nutritious delicacies. In the case of tiger sharks, the young animals even eat some of their siblings in the womb, so that they are born as cannibals. In addition to this active cannibalism, passive cannibalism, i.e. eating dead or severely injured and immobile conspecifics, is also widespread. Many scavenging predators and birds, such as crows, are among these cannibals. And anyone who cycles on dirt roads in warm, humid weather has probably already seen nudibranchs feasting on other conspecifics they have encountered. But animals don't kill their own kind just to eat them. Infanticide - the killing of offspring of its own species, usually by males who do not even devour the young afterwards - is also widespread, for example in lions, brown bears, baboons, chimpanzees and numerous rodents. There are a number of explanations for this behavior, including stress in the male perpetrators or developmental disorders in the kittens killed. The most convincing explanation, however, is the following: Adult males in mammals mostly compete with one another for reproductive possibilities. These possibilities are limited by the availability of females, as they are usually not ready to conceive as long as they are suckling and caring for their offspring. Males who kill the offspring of other males make the affected female more ready to conceive and can then produce their own offspring more quickly. Even in territorial fights, usually between males, one of the opponents is sometimes killed by the other. This has been observed in lynxes, wolves, hippos, sea eagles and numerous fish, for example. The closest relatives of humans show a behavior that is in some aspects even comparable to human warfare: In several Central African forests, troops of male chimpanzees have been observed, which systematically patrolled the borders of their home area and targeted members of neighboring groups, especially adult males and Young animals, hunted and killed. In the context of competition between neighboring groups, you can gain a numerical advantage and ultimately gain access to additional resources. In summary, the killing of conspecifics is an ancient behavior that is widespread in the animal kingdom and, among other things, can ensure nutrition under difficult environmental conditions and optimize one's own reproductive success. The massive killing of alien conspecifics using weapons is reserved for humans - a dubious unique selling point.