Different species of carnivores usually aren't the best of friends, but a new study from the University of Tennessee, Knoxville has found that an unexpected friendship among wolves and hyenas has blossomed in the face of adversity created by an inhospitable environment.

The southern Negev desert in Israel is the most arid location where striped hyenas (Hyaena hyaena) and grey wolves (Canis lupus) are known to coexist. Among the region's remarkable features is a maze of canyons, and in those canyons are where researchers found a striped hyena running with a pack of gray wolves. 

It is believed that the unfavorable conditions of living amid an extreme desert, paired with the need to find food, facilitated an alliance between the two enemies.

"Animal behavior is often more flexible than described in textbooks," said study co-author Vladimir Dinets, an assistant professor of psychology at the University of Tennessee. "When necessary, animals can abandon their usual strategies and learn something completely new and unexpected. It's a very useful skill for people, too."

Even so, Dinets and co-author Beniamin Eligulashvili, an Israel-based zoologist, were surprised by their findings. Traditionally, striped hyenas are solitary hunters, only seen in company around a large kill.  Grey wolves, on the other hand, are social, but not with other species.

Stripped hyenas are known to fight epic battles with lions and African wild dogs and even steal kills made by leopards and cheetahs. Wolves are hunters, too, preying primarily on lynxes, coyotes and even dogs - their closest relatives.

When researchers first spotted hyena tracks mixed with gray wolf tracks, they assumed that the two animals had travelled across the same area at different times. However, a second track sighting revealed that, in some places, the prints of a wolf were on top of a hyena's print, suggesting that the animals had all traveled through the area at the same time. It was not until four years later that researchers observed a wolf pack traveling with a hyena in its midst.

It is still unknown if the same animals were involved in both cases, or if the observed behavior is an isolated case of something that happens regularly but has never before been documented.

Therefore, Dinets theorizes that both predators accept each other due to the mutual benefits of traversing the barren terrain together. For instance, wolves are more agile, able to chase and take down all large animals of the region, while hyenas have an especially keen sense of smell and are able to sniff out carrion from many miles away. An additional benefit of the uncanny friendship is that hyenas are also better at digging than wolves and have jaws that can crack open large bones and tin cans.

The study was published in the Feb. 10 issue of the journal Zoology in the Middle East.