Why Is This Deer Licking This Fox?

A cuddly island mystery

A buck licks the head of a small island fox in a grass clearing
Mmm, salty (Chris Lowe / California State University Shark Lab)

When Chris Lowe first saw the buck stoop to lick the small, silver-speckled fox, he thought his eyes might be playing tricks on him. He’d just gotten back from a run on Santa Catalina, a remote Southern Californian island where he studies sharks, and came upon the two animals in the scrub. Mule deer and island foxes, the rascally miniature descendants of gray foxes, are everyday sights on Catalina’s grassy hills. But to see them nuzzling was downright weird.

Was the buck simply nibbling on a plant behind the fox? Had the fox happened to hop in front of the buck’s face? Lowe dashed into his apartment to grab his camera, and made it to the window to catch the deer taking another lick. The fox, docile in the shade of its antlered friend, wasn’t just tolerating the apparent cleaning, Lowe realized. “It looked like it was actually enjoying this,” he says.

Lowe tweeted a picture of the curious scene a few hours later, and it quickly racked up several thousand likes and retweets. In the image, the buck has its pursed lips planted on the fox’s forehead. The fox, its eyes closed, resembles a dog getting a good behind-the-ears scratch. People responding to Lowe’s tweet were captivated by the strange pairing. It was adorable—in one person’s words, “a Disney moment!” And no one had ever seen anything quite like it.

Well, no one except Michael Cove. To match Lowe’s tweet, Cove offered picture of his own: a lean doe in a forest rubbing noses with a cat. “We get this all the time in the Keys ... interesting that it is happening on islands,” he wrote. Then he brought the party down: “Certainly a pathway for disease transmission.”

One of a few cat-licking incidents Michael Cove’s motion-triggered cameras have captured (Michael Cove)

Cove, a mammologist at North Carolina State University who spends several months each year on the Florida Keys, has in fact spotted several peculiar meetings between the islands’ diminutive Key deer and other creatures. Motion-triggered cameras he’s set up around a wildlife refuge on one of the islands have photographed a deer dancing around a peacock, and a deer getting its face groomed by raccoon. There are a few more cases with cats, including a time off-camera that Cove passed a dumpster and saw two deer licking the same cat at once. (“The Florida Keys are an interesting place,” he says.)

Cove speculates that cut-off places like the Keys and Catalina, which is one of California’s eight Channel Islands, have two features that could encourage such interspecies intermingling. The most prominent is a lack of large predators. The islands’ deer have lived for generations on verdant floating worlds devoid of wolves, mountain lions, and other sharp-toothed threats. It’s possible their isolation has granted them a peace of mind that mainland deer can’t afford. Perhaps by now they don’t even know they could be afraid of other curious creatures.

The second is geography. Since an island’s inhabitants have limited land to roam, it’s easy for them to bump into each other. And as Cove points out in a new research paper in the journal Mammalian Biology, the scattered centers of human activity in the Keys attract animals that can find easy meals, pulling them into an even tighter orbit. The paper focuses on the Key deer and raccoons, but the same could likely be said of cats and island foxes, the latter of which are known to beg tourists for food and sneak off with your peanut butter even though you left it safely on your campsite’s picnic table, you swear.

These two factors account for a greater probability of animal-to-animal encounters on islands, but they don’t explain what would convince a deer to run its tongue over a cat or fox in the first place. Moreover, there’s evidence that this licking isn’t an island thing exclusively: Deer are occasionally spotted giving tongue baths to cats, at least, in mainland backyards. The exact motivation behind this behavior is much harder to pin down.

There’s a temptation to describe their interactions as mutually beneficial, in line with the natural world’s other astounding instances of species-to-species symbiosis. When Lowe first saw the buck and fox together, for example, he was reminded of underwater “safe zones,” where “predators and prey all line up to get cleaned” by small fish that munch on parasites.

Yet as Gary Roemer, an ecologist at New Mexico State University, points out, scientists reserve the concept of mutualism specifically for relationships in which both sides benefit in ways that help them survive. The dynamic is conceivable for Key deer and raccoons; in Cove’s camera-trap photos, a slinking raccoon takes a doe’s snout into its paws and nibbles around the patient animal’s eyes and ears, probably hungry for a snack of ticks. Neither Cove nor Roemer, who spent years studying island foxes earlier in his career, however, are convinced licking does much for the ecological fitness of deer, foxes, or cats.

This raccoon has also been photographed by a camera trap grooming a doe. (Michael Cove)

Both researchers suggested what might be a more obvious benefit for the foxes and cats: Getting licked feels good. “Maybe deer are getting those hard to reach places,” Cove says. As for the deer, ocean breezes cover islands—foxes and cats included—in salt. Cove has a theory that deer on islands particularly might be lured into the cleanings by a little extra seasoning.

But Cove’s tweet about disease transmission also underscores the much more ominous way these pictures can be read. Even if it feels and tastes nice, contact between animals isn’t necessarily positive, because it can cripple populations by passing along rabies, roundworms, and plenty of other viruses and parasites. These dangers are especially threatening in locations where the entirety of a species resides. Key deer and island foxes, both endemic to their respective coastal islands, have each been pushed to the edge of extinction in the past. If their newly observed canoodling sessions hint at any larger changes in island ecosystems, they conceivably are causes of concern.

But Roemer cautions against the impulse to read anything more into a few documented instances of deer licking smaller and probably salty animals than what they perhaps most clearly seem to be: two wild creatures inquisitive enough to give each other a closer look. “This is probably a novel, random, curious interaction,” he says of the buck and the fox. “It probably doesn’t have much significance either from an evolutionary or an ecological standpoint.”

(Roemer doesn’t buy the salt theory, either: If plants and rocks are also coated by the breeze, he reasons, it wouldn’t make sense for a deer to go through the trouble of tracking down a moving, claw-possessing island resident for tastiness alone.)

Busted (Chris Lowe / California State University Shark Lab)

Still, randomness leaves open two opposite conclusions about interspecies encounters like these. It’s possible—if not certain—that animals bump into each other in all kinds of undiscovered ways. “[Camera traps] are opening our eyes to just how fascinating the natural world is,” Cove says. “There are tons of species interactions that we might have never noticed just casually walking around the woods and stuff.” Key deer might not lick cats for a reason, but that doesn’t mean they don’t do it often.

Then again, it might be misguided to say what all deer on an island do in the first place. “More and more, we’re recognizing that, just like us, animals have different personalities,” Roemer says. “Sometimes they do bizarre things.” While working on one of the Channel Islands, he befriended an exuberant island fox named Josie, who made a game of goading a nature conservancy’s surly hunting dog into chasing her up trees.

So maybe it was an especially bold buck and a uniquely lonely fox that met under that fading afternoon sun on Santa Catalina Island. They neared each other in the brush of the only land they’ve ever known. And when they were close enough to touch, they were both filled with enough wonder to decide: why not?