Kleptoparasites: 8 Animals That Steal From Others

Oh, these cunning creatures. In behavior that requires athleticism and grace as well as planning and decision making, kleptoparasitic animals prove that it really is a dog-eat-dog world out there. Using this sly foraging strategy, animal thieves steal food already procured by other animals. If you’ve ever had a brazen seagull snatch a sandwich from your picnic at the beach, you’ve played host to a kleptoparasite. And gulls aren't the only guileful ones — the following are some of the animals especially adept at pulling a fast one when it comes to pilfering a meal.

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Chinstrap Penguins

chinstrap penguin standing on beach

Christopher Michel/ Flickr / CC by 2.0

Obviously, the charming chinstrap detail was designed to mimic a smile to distract from the fact that these cutie-pie penguins are prone to robbing others' nests of materials to use for their own. While most commonly kleptoparasitism refers to animals that steal food, lifting shelter materials from others gains the chinstrap penguin entry into this motley crew.

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Sperm Whales

A mother sperm whale and her calf off the coast of Mauritius. The calf has remoras attached to its body

Gabriel Barathieu / Wikimedia Commons / CC BY 2.0

We humans have been so rough on the whales, it would be hard to be a member of Team Whale and not feel a glimmer of glee about this. In one of the best, "Oh yeah? Take that" moments in the battle of man vs. nature, sperm whales habitually pilfer fish from fishermen. In Alaska, sperm whales are estimated to pick at least 5 to 10 percent of sablefish off of longlines, and sperm whales have also been spotted sneaking fish from nets. Yes, it's rough on the fisherman, but still. Justice through kleptoparasitism is kind of awesome.

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Western Gulls

Fishermen catch the most valuable species, and discard those that have non commercial value. They throw them into the sea, and the seagulls take the opportunity to catch them and eat them.
Luis Diaz Devesa / Getty Images

Some seabirds, like the tern dive into the depths to capture fish and other seabirds, like the Western gull, are not diving birds. So how is a non-diving bird supposed to catch fish? They take them straight from the beak of a diving bird or from the deck of fishing boats.

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Dewdrop Spiders

Red and Silver Dewdrop Spider on web belonging to another spider

Photo: Jeevan Jose / Wikimedia Commons / CC BY-SA 4.0

Spiders from the Argyrodes genus, commonly known as dewdrop spiders, are some of the brassiest kleptoparasites around. Not only do they steal prey from other spiders' webs, but they invade and move into said webs as well. While the relationship can be beneficial to both spiders since the dewdrop will clean up smaller prey that would otherwise litter the web, things can turn grim quickly when the invading spider decides to devour the host as well.

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Water Crickets

water cricket sitting on pond leaf

Photo: Mike Pennington / Geograph / CC BY-SA 2.0

The cutely named water cricket (Velia caprai) — a surface skating aquatic bug — has all kinds of sophisticated cricket tricks to perform. Along with developing such a terrible taste that trout actually spit them out unharmed, they are also known for their "expansion skating" whereby they spit onto the water to lower the surface tension, which allows them to increase their travel speed by double. They are also great as practicing group kleptoparasitism. If one has some purloined prey that is too heavy to transport, other water crickets come to the rescue and help eat the prize.

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Hyenas

spotted hyena on savanna in Tanzania

Photo: Anja Pietsch / Flickr / CC BY 2.0

Hyenas are no laughing matter. Haha. But really, a quick image search reveals any number of photos of fierce-looking hyenas gadding about with things like severed bloody zebra heads in their maws. They are fascinating creatures, but they don't mess around; an adult spotted hyena can rip off and devour 30 or 40 pounds of flesh per feeding. And while they are very adept hunters, they have no problem chasing off a pride of lions to finish off the lion's share.

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Cuckoo bees

cuckoo bee holding on to plant using only mandibles

Gilles Gonthier / Flickr / CC BY 2.0

Much in the way its namesake, the cuckoo bird, lays eggs in another bird's nest, the cuckoo bee also displays similar parasitism. But whereas the cuckoo bird chick is then raised by the other bird as its own, the cuckoo bee's plotline takes an even more sinister turn. Mama cuckoo bee lays her eggs in another bee’s nest, but the cuckoo bee larvae hatch earlier than others, allowing it to feed on the provisions in store for the home bee's larvae. And then the cuckoo bee babies, with their extra-large mandibles, make mincemeat of the other larvae as well.

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Humans

Two beekeepers lifting frame from bee hive
Peter Muller / Getty Images

Do you think we're above and beyond a bit of parasitism? The truth is, we're master kleptoparasites! There are many instances of people stealing food from other people, but we lift edibles from other species as well. Many people around the world rely on food killed by lions or other large carnivores, for example. And even closer to home, chances are you might be a kleptoparasite as well; have you eaten any honey lately?