In 2020, a viral video of an unusual interaction between a badger and a coyote charmed the internet. Filmed by a remote sensor camera in the Santa Cruz Mountains of California, the video Pictures showed the two animals He stepped into a culvert to pass under a highway. Tail wagging, the coyote leapt toward the badger and then away, stopping to see if the badger would follow. The badger hurried to catch up with his companion, and they trotted together into the tunnel.
Their playful behavior suggests that the pair share a friendly bond. But can animals really be friends, like humans are?
In many species of social animals, certain behaviors suggest that individuals may indeed be closer to some than others (in addition to close relatives or partners). Male dolphins that feed on sponges hang out with other males who have a similar foraging styleElephants use specific greetings for other elephants they know. Primates demonstrate intimate bonds with non-relatives through groomingCrows are also known to groom some of the crows in their flock, smooth them with their beaks.
“Individuals form social relationships to navigate their environment,” he said. Delphine DeMoorpostdoctoral researcher in behavioral ecology at the University of Exeter in the United Kingdom. For highly social animals, relationships are defined by varying levels of trust and intimacy, De Moor told Live Science. Patterns of interaction shape these bonds; trust develops when repeated interactions are positive.
If animals can form stable, lasting and mutually beneficial bonds – qualities found in human friendship – “then we see friendship in the animal kingdom,” De Moor said.
Scientists who study primates have discovered that neurochemistry plays an important role in strengthening these bonds, according to Catherine Crockfordresearch director at the National Center for Scientific Research (CNRS) in Lyon and head of the Great Ape Social Mind Lab.
In primates, grooming releases the behavior-regulating hormone oxytocin, “which then feeds into the reward center, which likely provides a positive feedback system that increases the likelihood of grooming again,” Crockford told Live Science. Grooming a friend also reduces cortisol, a hormone associated with stress. In contrast, cortisol levels were unaffected when monkeys groomed a group member with whom they had not formed a bond, Crockford added.
“There appear to be physiological benefits that one gets from doing something like grooming specifically with a bond partner,” she said.
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Scientists first reported reciprocal friendships among primates through observations of matrilineal monkey groups, but recent decades have provided a growing body of evidence about friendship and its benefits in other mammals, Crockford said.
“People who are able to maintain these strong relationships end up living longer, having more offspring and showing fewer signs of stress,” she said. “It really seems like if you can maintain these types of relationships, they get very significant benefits from it.”
For example, orcas share food and information on where to find food; orcas that have strong bonds within their pod are less likely to starve when resources are scarce. Hyenas with more friends tend to achieve more success within their clans, as they have support for social challenges.
But friendship also involves responsibilities, De Moor added. “At some point, animals are willing to take much more risks and engage in much more costly behaviors for their preferred social partners.”
Consider the self-sacrifice of a vampire bat helping a hungry friend in sharing recently eaten meals and regurgitating blood into a friend’s mouth (and if you haven’t vomited into your friend’s mouth recently, can you even consider yourself a friend?).
In chimpanzees, friendship bonds can be so strong that if a mother dies and leaves a dependent young, “a male or female friend (of the parent) can adopt that child,” Crockford said. Raising a young comes at a cost to the new parent, especially if the adopter is a male, she added.
“His overall pace of life has to slow down,” Crockford said. “He’ll have to carry his offspring or go at their pace, and share his nest with them at night, and won’t be able to get involved as easily in group interactions or aggressive interactions with others.”
Interspecies friendship
Mutual trust can also exist between species. In 2022, a revolutionary study have shown that wild chimpanzees and gorillas in the Republic of Congo can cross the species barrier to form friendships that last 20 years or more.
In some cases, animal friendships are formed through human intervention. Cats and dogs who share a home often develop close bonds. At a private zoo in Belgium, a family of Orangutans make friends with otters in the wildafter zookeepers combined their habitats. A lion and a dog In Mexico, two lionesses who were raised together (the lion was kept illegally as a pet) remained close after both were transferred to an animal rescue center.
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Although the playful camaraderie between badgers and coyotes in California has never been observed before, such interspecies relationships may be more common in nature than scientists think, De Moor said. Much more is known about animal friendships in some groups — primates, elephants and dolphins, for example — simply because their social behavior has been observed for decades, with some relationships studied throughout the animals’ lives.
“We only know what we study, and we don’t know what we don’t study,” De Moor said.
Evidence for friendship among animals in general (and primates in particular) sheds light on the evolution that shaped the human capacity for friendship, Crockford noted. Our last common ancestor with apes lived about 25 million years agoSo the neurochemistry behind human friendship and associated behaviors has been around for millions of years.
“These mechanisms are deep and ancient,” she said. “In this day and age, when people value other things more than friendship—like money, fame, or clicks—it reminds us that a fundamental part of who we are is designed to have friends. And if we can have friends and treat them seriously, we will live longer, healthier, and less stressed lives.”