What do you get the walrus that has everything?

Don’t waste your money on Furbys and Tickle Me Elmos. According to a new study, what walruses really want to play with are bird carcasses.

It may surprise you to learn that walruses are playful creatures—and you wouldn’t be alone. Compared with more jovial sea lions and seals, even scientists have long thought of the 1.5-ton walrus as the most humorless pinniped. But according to study co-author Andrey Giljov, a zoologist at St. Petersburg University, this prejudice may stem from the fact that walruses are poorly studied.

Play or Prey? Watch Walruses Interact With Seabirds WATCH: Walruses were observed exhibiting a wide variety of behaviors around seabirds in the Chukchi Sea.

That's why Giljov and his fellow zoologist Karina Karenina spent a month in 2015 observing a huge group of walruses on Kolyuchin Island (map) in the Chukchi Sea near Russia. To avoid interfering with the animals’ behavior, the researchers perched atop an icy cliff, braving bitter winds and the risk of falling into the midst of several hundred snoring beach behemoths. (See "Biggest Walrus Gathering Recorded as Sea Ice Shrinks.")

In the end, the toil was worth it. Giljov and Karenina observed 74 interactions between walruses and seabirds and noted several different kinds of play—the first such observations for this species.

"The reasons why young walruses engage in such behavior are probably the same reasons why all animals begin to play,” says Giljov, whose study appeared recently in the journal acta ethologica. “Play may be important for the development of physical and social skills.”

Any Bird Will Do

Researchers have known for some time that young male walruses play-fight on the beach. This is thought to prepare them for competing against rivals when it comes time to breed.

But what’s new about this paper is the way walruses of both sexes appear to use birds as toys. (Also see "Crocodiles Play, Too, Study Says—Why Do Animals Have Fun?")

Sometimes the walruses would sneak up on live birds floating on the water and scare them away. Other times they’d dive down below the birds and rear up out of the water at the last minute, attempting to slash the unsuspecting fowl with their tusks. Glaucous gulls, kittiwakes, tufted puffins—walruses do not seem to care about the species. So long as it was avian and floating, it seemed fair game.

Young walruses, among which a vast majority of the interactions occurred, are nearly impossible to sex from a distance, says Giljov; however, he suspects both immature male and female walruses engage in play, since behavioral differences don't usually show up until the animals are older.

Though it was far less frequent, the researchers did also observe play in adults, citing 13 instances of males playing with birds. Adult females were observed playing just twice.

Interestingly, only one of these 74 encounters resulted in the bird’s death, suggesting that the walruses aren’t really trying to kill their playthings.

Whole New Ball Game

“The most interesting type of play observed was an object play,” says Giljov, “when one or several walruses used seabird carcasses as ‘toys.’”

In this game, the walruses made use of bird carcasses that had either been dropped by birds of prey or washed in with the tide. The walrus would grab the carcass and drag it underwater and let it float back to the surface, at which point the walrus would swim up and drag it down again—as many as eight times in a row. (See "Chimp 'Girls' Play With 'Dolls' Too—First Wild Evidence.")

In another instance, one walrus grabbed a seabird carcass in its mouth while a group of other walruses formed around it to jostle and lean on the carcass holder. If the carcass holder released its grip, another walrus would snatch the bird up and take its turn in the center of the circle, sort of like a group of children fighting over a football.

Giljov notes that one walrus was even seen taunting its buddies when they lost interest by placing the carcass near their heads and then stealing it back before they could grab it.

“Such a complex play behavior is not often observed in nonprimate animals,” he says.

Is It Really Play?

In 10 interactions with bird carcasses, the researchers observed walruses eating dead birds—even though walruses typically dine on shellfish. So does this mean we should view the other chase interactions as attempts to catch prey, rather than lighthearted play?

Well, it might be a little of both.

According to Gordon M. Burghardt, a comparative ethologist at the University of Tennessee and author of The Genesis of Animal Play, play is often derived from other behaviors such as courtship, fighting, and feeding.

“Think of a cat playing with a rubber mouse, or even real dead ones before eating them,” he says, “[or] dogs retrieving sticks as compared to retrieving prey.”

Burghardt admits he’s not versed in walrus behavior specifically, but he does believe that the researchers’ observations fall under the definition of animal play: repeated, pleasurable behavior that's similar, but not identical, to other behaviors in which the animal regularly engages. It also must be seen when the animal is healthy and not under stress.

He adds it’s crucial that we study species not typically thought of as being playful—from walruses to insects to fish—in order to better understand the fascinating phenomenon.

This vote of confidence will surely come as good news to Giljov, who says he saw the sun only three times in the month he spent on Kolyuchin Island and that it took another six months before the stench of walrus feces came out of his field clothes.

“However, it was not miserable or disheartening for us, since the severe nature of the Arctic has its own beauty.”