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It’s said that laughter is the best medicine, but it’s also one of the most multifaceted reactions. Humans use laughter to bond with other humans and to express joy. Laughter has even been shown to soothe the nerves and have a psychological effect on stressful or awkward situations. But while laughing is commonly considered a purely human response, several members of the animal kingdom can be heard cackling through the day and night for a number of reasons.

The animal kingdom is full of family connections, and some relations are easy to spot: lions and tigers, horses and zebras, dogs and wolves among them. 

But evolution isn’t always so obvious—over time, related species can develop completely different shapes, sizes, behaviors, and lifestyles, even if they share a family tree. Sometimes, the result is a pair of animal relatives that look like they couldn’t possibly be related. Take a look at five animals with surprising cousins.

Animal coat patterns are some of nature’s most striking designs, whether it’s a tiger’s bold black stripes or a leopard’s intricate rosettes.

But as striking as they are, an animal’s markings go well beyond aesthetics; these patterns have evolved through natural selection to aid in survival. But why do some animals have spots while others have stripes? Is there a functional difference, or is this just a quirk of evolutionary fate?