Before Wally and Ann Collito, of North Attleborough, Massachusetts, had a chance to befriend the stray kitten that had appeared in their yard, the couple discovered that another caring being—a crow—had already done so.

Over the next few months, the Collitos witnessed an incredible friendship develop between the crow and cat they respectively named Moses and Cassie. The pair romped in the grass, swatting gently at each other like they were born playmates, rather than sworn enemies. Moses often dropped nutritious worms and bugs in the kitten’s mouth, following it around like a protective parent.

“If it wasn’t for the crow feeding and taking care of that cat, it would have been dead a long time ago,” relates Wally Collito in a video posted at InterspeciesFriends.blogspot.com. “When the cat would start crossing the road, the crow would holler as if to say, ‘Don’t go in the road, you’re going to get hit.’ Sometimes she would get in front of her and push her back on the sidewalk. It had to be love or friendship.”

The story of Moses and Cassie is not an anomaly, but rather an indication of the potential emotional bond between animals, according to Jennifer S. Holland, author of Unlikely Friendships: 47 Remarkable Stories from the Animal Kingdom. “A number of years ago, it was really taboo to attribute empathy to other animals,” she says, “but more scientists today are crossing that line comfortably.” She explains that no one really knows what emotions animal experience or how, although humans share the brain’s limbic system, considered the seat of emotions in humans, with other mammals. “There is no reason they don’t have experiences similar to ours in terms of basic emotions,” Holland surmises.

Holland’s new book is just one of a growing number of efforts to document the wild landscape of interspecies love, including blogs dedicated to the topic and countless children’s books; one of them, Cat and Crow, by Lisa Fleming, immortalizes Moses and Cassie. “Such stories give us a sense of hope at a time when there is a lot of negativity in the world,” observes Holland. “I think people are looking for a reprieve.”

Mother Love Knows No Bounds

A variety of recent studies by the likes of the University of Cambridge and Max Planck Institute for Evolutionary Anthropology indicate that empathy and altruism may be characteristics of species ranging from squirrels to sea lions. Consider the adventures of Finnegan, a squirrel that had fallen out of its nest and into the loving abode of Seattle resident Debby Cantlon. Her pregnant papillon, Mademoiselle Giselle, adopted the injured squirrel, pulling its cage close to her own dog bed. Giselle continued to care for Finnegan after she had her own litter, literally nursing the squirrel back to health.

“The drive to nurture and be nurtured is strong, particularly when an animal has lost its baby or parent. This story is a perfect example of the mothering instinct coming to life,” says Holland.

Like many human friendships, some unusual animal pairings develop out of the basic need for companionship. One well-known example is Tarra, an 8,700-pound former circus elephant retired to The Elephant Sanctuary, in Hohenwald, Tennessee. Elephants are known to pair up, but Tarra chose to instead bond with a rescued stray dog named Bella. The two became inseparable pals and Tarra proved to be no fair-weather friend: When Bella suffered a spinal cord injury, Tarra stood sentinel at the gate outside the sanctuary office, waiting three weeks for Bella before she could be carried outside for a happy reunion.

Baloo, the bear, Leo, the lion and Shere Khan, the tiger, were each just two months old when they were rescued during a residential drug raid. Noah’s Ark Animal Rehabilitation Center, in Locust Grove, Georgia, took in the trio, and the “BLT” (bear, lion and tiger) became so close that the sanctuary spent thousands of dollars to build a special clubhouse to house them. Eight years later, the three animals—each hailing from different continents—still live like blood brothers.

If peace between traditionally antagonistic species is possible, the implications for mankind are obvious. When basic needs are met, the instinct to protect or play can trump the urge to grab, neglect or fight. We can all share and get along better when we take responsibility for creating the circumstances to support that ideal.

“I joke that we should give my book to politicians to remind them that a lot of good can come from crossing boundaries,” smiles Holland. “Kindness and companionship can mean survival for all kinds of animals; that goes for humans, too.”

April Thompson is a freelance writer in Washington, D.C. Connect at AprilWrites.com.