At a wildlife park in Germany, observers were surprised when a young ring-tailed lemur attempted to initiate a playful wrestling match with an adult ruffed lemur.
The two species of lemurs don't ordinarily interact. And there was some concern that the adult lemur would take the playful advances of the young lemur the wrong way and react aggressively.
Instead, the adult lemur rolled over on its back and invited contact.
In February's edition of Frontiers in Ecology and Evolution, the researchers documented lemur encounters, as well as others, in what they described as "rare" and "dangerous" examples of "interspecies play."
You're more apt to see two different species at play when they're held in captivity. We see it all the time in homes that host both cats and dogs as pets. If the puppies and kittens are brought up together, they are likely to become so familiar with each other that the barriers that would normally keep them apart come down.
Those barriers include how one member of a species communicates with another. Vocalizations, visual signals, and even olafactory cues are learned by members of the same species at a young age so that the cues that lead to play are well understood.
What happens when members of two different species confront each other? Those same play cues are useless, which could lead to play being misinterpreted as aggression.
“It would be a critical mistake to keep antagonizing a play-fighting partner when they are no longer interested—an event likely leading to real aggression and the risk of physical or social harm,” says Dr. Heather J.B. Brooks, an animal behavior specialist and postdoctoral researcher at the University of Colorado, Boulder.
“These risks are common when playing with the same species, but they are likely even more problematic when we start to examine interspecies play," says Dr. Brooks.
Cats and dogs in the care of humans live in much closer proximity than they would normally would. “Close proximity allows animals to become more comfortable with one another and likely also more confident in the ability to correctly read the other individual’s play signals,” says Brooks.
In the wild, young animals tend to be more playful than their adult counterparts, Brooks notes, “because their needs are met by parental care.” So while mom rests, baby is looking for someone to play with—even if that someone is from a different species.
For example, at Gombe Stream National Park, Jane Goodall noted a recurring relationship between a young chimpanzee named Ferdinand and a young olive baboon. While these two animals have more in common than other pairs, such as a dog and a bearded dragon, “chimpanzees are predators of olive baboons in adulthood, so there is still an added layer of danger,” Brooks notes.
“Young animals that do not have access to similarly aged individuals from their own species may be more inclined to play interspecifically,” Brooks says.
In the wild, there have been many documented instances of predators playing with their prey. Predators like cats and orcas may temporarily release caught prey only to catch it again, which helps hone their reflexes and coordination. Falcons may engage in aerial chases with prey species, such as terns, without immediately finishing the kill, a form of behavior often called "play."
If you've had both cats and dogs as pets, you probably have your own unbearably cute stories of dogs and cats playing together, sleeping together, and cleaning each other.
And then there are the stories where your dog and cat don't get along, and you have to watch them carefully to prevent catastrophe. We really needn't worry. The two species eventually establish an unwritten set of rules of possession so that certain pieces of furniture or parts of the house are "out of bounds" to the other. Trespassers be forewarned.
My family had a golden retriever that enjoyed terrorizing our two cats, chasing them endlessly around the house, growling and barking at them during the day.
At night, they'd all curl up together and fall asleep. Go figure.
