We know that sometimes animals have unlikely friendships. Whether it's circumstances that throw them together or they just happen to find a friend from another species, animals will occasionally become pals, creating an unconventional alliance.
These unusual relationships cause a certain amount of double-takes — and they're often incredibly adorable — but there's also a scientific benefit to studying odd animal friendships.
“There’s no question that studying these relationships can give you some insight into the factors that go into normal relationships,” Gordon Burghardt, a professor in the departments of psychology and ecology and evolutionary biology at the University of Tennessee, told The New York Times.
Cross-species bonds typically occur in young animals, and they're also common among captive animals that have no choice but to seek each other out.
“I think the choices animals make in cross-species relationships are the same as they’d make in same-species relationships," Marc Bekoff, professor emeritus of ecology and evolutionary biology at the University of Colorado, told Slate. "Some dogs don’t like every other dog. Animals are very selective about the other individuals who they let into their lives.”
And when predator and prey become buddies, that requires serious trust from the animal on the prey end, Bekoff points out.
The polar bears at SeaWorld San Diego in happier times. (Photo: samantha celera [CC BY-ND 2.0]/Flickr)
Animal friendships — whether in their own species or outside — can be very meaningful. Consider the story of Szenja, a 21-year-old polar bear who died at SeaWorld San Diego in mid-April after an unexplained illness including loss of appetite and energy, according to The San Diego Union-Tribune. Szenja had recently been separated from her long-time companion, Snowflake, who had been sent to the Pittsburgh Zoo & PPG Aquarium for a breeding visit. The pair had been together for 20 years. The polar bears made headlines in March when more than 55,000 people signed a petition not to separate the "best friends."
In a statement, PETA Executive Vice President Tracy Remain said Szenja died of a broken heart.
Here's a look at some animal odd couples that have forged lasting bonds.
A llama nuzzles its sheep friend. (Photo: Katriona McCarthy [CC BY 2.0]/Flickr)
Editor's note: This story has been updated with new information since it was published in April 2017.