Dolphin fish image8/14/2023 ![]() ![]() This walk through some of the grimmer aspects of the behavior of animals serves as a reminder that nature can be brutal. Is the behavior distasteful to us? Yes, but then again, nature does not care what you think. Read: Is human morality a product of evolution?Īre dolphins murderers or rapists? No, because we cannot apply human legal terms to other animals. One study in the 1990s reported nine that had died of blunt-force trauma, including multiple rib fractures, lung lacerations, and deep puncture wounds that were consistent with bites from an adult dolphin. There are plenty of reports of dolphin calves washed up on beaches with extreme injuries. Their sperm mixes internally in the female, and she will give birth to offspring of several paternities in a single litter. Female cheetahs get around all these issues by copulating with multiple males. Alpha-female meerkats will kill the litters of subordinate females so that they will be free to help nurture the alpha’s litter. Mother-and-daughter teams of chimps in Tanzania have been seen killing and eating the babies of other parents for reasons that are not clear. Males acting alone or sometimes in packs will kill her young in order to bring her back to being fertile so they can then sire a pride. It often gets translated into murder in the popular press, but it should be noted that in plenty of other organisms, both males and females kill the young of others within their own species as a reproductive strategy.Ī female lion lactates for more than a year when she is nursing cubs, and during this time won’t breed. Infanticide is another unpleasant behavior seen in dolphins. But we must be careful not to anthropomorphize their behavior, whether it be cute, smart, or horrid. There is no doubt that sexual coercion is part of their reproductive strategy, as it is in many organisms, and that the behavior is violent. Many people say semi-jokingly that in contrast to their cute and smart image, dolphins rape. The evidence comes from observations of the precopulatory behavior, and physical evidence of violence on the females. It should be noted that forced copulation has not been directly witnessed, as far as I am aware. These gangs don’t tend to be closely related. On occasion, they form looser “super-alliances,” where multiple second-order gangs will join forces-up to 14 individual males-to corral a single female. The males are often closely related in these alliances, so as a means of transferring their genes into the future, this fits perfectly well within evolutionary theory. ![]() Second-order alliances do the same, but the team-up makes a ratio of five or six males to one female. Read: If you insulted a dolphin 20 years ago, he’s probably still bitter about it ![]() The males restrict her attempts at freedom by charging in, and bashing her with their tails, head-butting, biting, and body-slamming her into submission. During this aggressive corralling, the female repeatedly tries to escape, and does so in about one of every four attempts. First-order partnerships will single out a female, rush at her, and then herd her away to have sex, which is coercive (this is a general assumption, because it is rarely seen). The bottlenose dolphins have a different tactic: They form gangs.Īlliances are an essential part of the mating strategies of the males. In most cases in nature, that competition is between individual males. When breeding season comes around, there is fierce competition for access to females, as happens in many sexual species. These Shark Bay dolphins are also viciously violent. Sometimes two pairs will team up and form a second-order alliance. Two or three male Shark Bay dolphins will form a gang that swim and hunt with each other, called a “first-order” pair or trio. They also have complex societies, among them notably (but certainly not exclusively) the bottlenose dolphins best studied in Shark Bay in Australia. ![]() They are smart and have large, complex brains. This post is adapted from Rutherford’s new book.ĭolphin is a loose and informal name for several different groups of cetaceans, including the Delphinidae (ocean dolphins) and three classes that live in rivers or estuaries (Indian, New World, and brackish). ![]()
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