{"id":2190672,"date":"2026-04-11T06:00:03","date_gmt":"2026-04-11T04:00:03","guid":{"rendered":"https:\/\/focusingonwildlife.com\/news\/?p=2190672"},"modified":"2026-04-02T15:12:08","modified_gmt":"2026-04-02T13:12:08","slug":"they-bore-the-marks-of-an-attack-including-rib-fractures-internal-haemorrhages-and-specific-teeth-marks-5-animals-that-kill-excessively-seemingly-just-for-fun","status":"publish","type":"post","link":"https:\/\/focusingonwildlife.com\/news\/they-bore-the-marks-of-an-attack-including-rib-fractures-internal-haemorrhages-and-specific-teeth-marks-5-animals-that-kill-excessively-seemingly-just-for-fun\/","title":{"rendered":"\u201cThey bore the marks of an attack, including rib fractures, internal haemorrhages and specific teeth marks.\u201d 5 animals that kill excessively \u2013 seemingly just for fun"},"content":{"rendered":"

At 10am on 27 June 2018, researchers studying dolphins in a Belize mangrove, witnessed a gruesome spectacle. First, a group of four bottlenose dolphins separated a baby manatee from his mother. Then, one of them attacked the calf, biting it over and over again, and ramming it out of the water. The youngster later died from its injuries.<\/p>\n

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Animals kill other animals all the time, but there is usually an explanation. Animals kill for food, for dominance, for mating rights or to avoid being killed. Sometimes, however, there is no obvious motive.<\/p>\n

Dolphins\u00a0don\u2019t eat\u00a0manatee\u00a0calves, nor are manatee calves a threat to the cetaceans. According to the scientists who witnessed the encounter, the aggressors here had nothing to gain. Not was this a one off.<\/p>\n

Between 1999 and 2020, researchers documented ten baby manatee attacks by dolphins, of which at least two were fatal.<\/p>\n

When animals kill excessively, it\u2019s called surplus killing. Dolphins killing manatees is one example, but the term is typically used to describe the behaviour of predators which kill more prey than they can immediately eat.<\/p>\n

Foxes, for instance, will sometimes kill a glut of chickens, leading to the practice\u2019s alternative name of \u2018henhouse syndrome.\u2019 Here are five animals that practice surplus killing.<\/p>\n

Animals that kill for fun<\/h2>\n

Bottlenose dolphins<\/h3>\n
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\"Bottle
Bottlenose dolphins are highly intelligent and are quick learners – by wildestanimal\/Getty Images<\/figcaption><\/figure>
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Dolphins don\u2019t just kill baby manatees \u2013 they also kill porpoises. Harbour porpoises are smaller and lighter than bottlenose dolphins, so they pose no threat. They are also not eaten.<\/p>\n

In recent years, researchers have documented a growing number of dolphin-on-porpoise attacks. In\u00a02016, six porpoises were part of a larger group found stranded on the Baltic Sea coast of Schleswig-Holstein.<\/p>\n

The two calves and four adults stood out because they bore the characteristic marks of a dolphin attack, including rib fractures, internal haemorrhages and specific teeth marks that match the mouths of dolphins. Similar attacks have also been documented in\u00a0UK\u00a0and\u00a0American\u00a0waters.<\/p>\n

Orcas<\/h3>\n

Porpoises do not get off lightly.\u00a0Orcas, otherwise known as killer whales, are not true whales but the world\u2019s largest species of dolphin.<\/p>\n

Over the last 60 years, one particular population, living off the north-west Pacific coast of North America, have chased down at least 78 porpoises, and killed\u00a028<\/a>\u00a0of them. Like the dolphins, they didn\u2019t eat the porpoises, but here at least, there is a possible explanation.<\/p>\n

The whales often targeted young porpoises that were similar in size to their preferred prey item, the adult Chinook salmon. Adult orcas engaged in the killing, but the behaviour was most common amongst juveniles. It\u2019s possible, therefore, that the porpicide was a form of hunting practice.<\/p>\n

Grey wolves<\/h3>\n

Grey wolves\u00a0are social animals that hunt and fell their prey in large, co-ordinated groups. Typically, the carnivores kill one animal at a time, such as an elk or a deer, and then feed on it for a couple of days.<\/p>\n

Waste not want not, they often\u00a0consume more than 90 per cent\u00a0of a carcass\u2019s edible bits, including organs, meat and bones. Occasionally, however, they go rogue.<\/p>\n

In winter 2016, one grey wolf pack is thought to have dispatched 19 elk in a one night. Nine individuals belonging to a group called the Rim Pack, killed two adult cows and 17 calves in Wyoming.<\/p>\n

Surplus killings like this are rare but when they do occur, it\u2019s often during the winter months when it may represent the wolves caching food for the hard times ahead.<\/p>\n

Midges<\/h3>\n
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\"Corethrella
A non-identified specimen belonging to the genus Corethrella, commonly known as frog-biting midges – Amaral.ap, CC BY-SA 4.0\u00a0, via Wikimedia Commons<\/figcaption><\/figure>
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Corethrella appendiculata\u00a0<\/em>is a little midge, with a life cycle comprising four stages: egg; larva; pupa and adult. Two of these stages are predatory.<\/p>\n

In their adult form,\u00a0Corethrella\u00a0<\/em>midges are specialised\u00a0parasites\u00a0that feed mainly on frog blood. In its larval form,\u00a0C. appendiculata\u00a0<\/em>lives in water-filled cavities in trees, where it predates other aquatic invertebrates, such as mosquito larvae.<\/p>\n

Sometimes, the larvae of\u00a0C. appendiculata<\/em>\u00a0really go to town. A single midge larva can kill around\u00a0200 mosquito larvae\u00a0by biting them on the thorax (the bit inbetween the head and the abdomen).<\/p>\n

This is far more than they can eat and is thought to be an adaptation to their crowded environment. They may kill extra prey to reduce competition from neighbouring species.<\/p>\n

Domestic cats<\/h3>\n
\"Domestic
A study of feral domestic cats found they have a kill rate of 32% – nomadnes\/Getty Images<\/figcaption><\/figure>\n

In the UK and many other countries, most\u00a0domestic cats\u00a0are well-fed by their owners. They don\u2019t\u00a0need\u00a0<\/em>to bring home dismembered bodies, yet the behaviour is so instinctive, very often they do.<\/p>\n

As part of a\u00a02025 UK study\u00a0called \u2018What the Cat Dragged in<\/em>\u2019, 553 outdoor domestic cats were monitored over three and a half years. While most cats brought home a maximum of one prey item per month, a handful of serial killers regularly returned over 15 individuals.<\/p>\n

Scaling the numbers up, this means that the UK\u2019s pet cats kill around 140 million wild animals per year, most of which are small mammals. This presents a threat to local wildlife, so if you\u2019re concerned, add a bell. Some\u00a0studies\u00a0suggest that cats which wear bells bring home less wildlife.<\/p>\n<\/div>\n<\/div>\n<\/article>\n

This article<\/a> by Helen Pilcher was first published by Discover Wildlife on 27 March 2026. Lead Image:\u00a0GeoStock\/Getty Images.<\/em><\/p>\n

What you can do<\/h2>\n

Protect wildlife by making a monthly donation as little as $5.<\/em><\/p>\n