It was a typical game drive for Patrick Njobvu in Zambia’s South Luangwa National Park—until he witnessed something unique in his 23 years of guiding.

As he and a vehicle of tourists watched on a recent July morning, a hippopotamus emerged from the Luangwa River and approached a sleeping spotted hyena, which soon awakened.

“The hyena didn't run and both started sniffing each other, nose to nose, almost like kissing,” Njobvu, the head guide at Shenton Safaris, told National Geographic by email. For almost 20 minutes, the young animals hung out together, touching noses, with the hyena rolling on its back at one point. “It was very strange indeed,” he says.

Njobvu later described the incident on the safari’s blog as a “hyena-hippo love affair”, but experts say it was instead likely a case of youthful curiosity.

“If I was to guess, I’d say that the young hippo was simply inquisitive about the hyena, who in turn wasn’t feeling threatened enough to leave because the hippo wasn’t being aggressive,” says Rob Heathcote, a behavioural ecologist at the University of Exeter in the U.K.

Young animals are inquisitive in part to help them test the boundaries and learn about unknown elements of their environments. “However, we can’t really say what this interaction is about, beyond speculating, since this kind of thing is too rare to study properly,” he cautions.

Fear factor

Arjun Dheer, who studies spotted hyenas in Tanzania’s Ngorongoro Crater, does not “doubt that there was some mutual curiosity,” but he adds that both animals were likely afraid of one another.