The Frivolous Function of Play

What is play? Which animals play? Why do animals play? What do scientists know about play? These questions may have surprising answers!

In this article, you will learn:

Go ahead and take a look!

(warning: post has a lot of videos of cute animals, so it may take time to load)

Do Crocodiles Play?

In a brand-new paper titled "Play Behavior in Crocodilians," Vladimir Dinets argues that not only do crocodiles play, but that they play in varied and complex ways. This may come as a shock to many people, used to thinking of reptiles as cold-blooded and emotionless- particularly crocodiles, which look like they've got nothing but murder on their minds 24/7. But looks can be deceiving.

Now, to be clear, Dinets' paper is not a formal study, and leaves plenty of room for argument that crocodilians (a group that includes crocodiles, alligators, caimans, and others) do not actually play. In fact, though the researchers spent roughly 3,000 hours observing crocodiles for other studies, they only recorded seven instances of play. The other instances were anecdotes collected from crocodile keepers and farmers.

Any good scientist knows that anecdotes don't provide conclusive proof of anything, but they are a good starting point. And the anecdotes are fascinating. They include tales of crocodilians surfing the waves, attacking (and courting) rubber balls, picking pink flowers, and even giving piggyback rides to other crocodilians. There are even reports of crocodiles playing with humans (Pocho the crocodile, pictured above, is mentioned) and one instance of an alligator playing with an otter.

These are all incredibly charming, of course, but it is quite possible to argue that they are not play. Firstly, what play actually is has been famously hard to define, and many animal behaviors once termed play have been found to have actual adaptive functions. For example, before it was known that male fireflies flashed to attract mates, early researchers thought it was for the sheer pleasure.

There is a lot we do not know about crocodilian behavior, in part because they are so different from mammals, right down to the metabolism. Frivolous activity is harder to justify when you are not warm-blooded and need to be more careful about conserving energy. And as with the fireflies, behaviors that apparently have no adaptive purpose can turn out to be performed for specific goals.

So do crocodiles play or not? My hunch is that they do, though probably not nearly as often or even in the same ways that mammals might. There is no conclusive evidence yet to confirm this. Still, of all the things that might interest a crocodile, I bet you never thought of "pink flowers."

Source:

Dinets, V. (2015). Play behavior in crocodilians. Animal Behavior and Cognition, 2(1), 49-55.

(This paper came out with perfect timing, because I am now writing an extensive article on the weird enigma of animal play. It should be out in the next couple of weeks!)

The Development of Social Behavior in Three South American Canids

Here's a neat paper from 1983.

The bush dog, crab-eating fox, and maned wolf are three species of canids from South America. The maned wolf is mostly solitary, with contact between males and females restricted to the breeding season and pup-rearing. Crab-eating foxes, by contrast, pair up and maintain territories together. Pups also sometimes remain with their parents past reproductive age, depending on territory availability.

Of all three species, the bush dog is the most social, living in packs much like the gray wolf or African wild dog does. This enables them to work together and kill prey much larger than themselves, like capybara.

At the time, these three species were all placed within the South American branch of Canidae, distinct from the true foxes and the true dogs. (This has since been challenged.*) The paper's author, Maxeen Biben, chose to compare them because they had such a range of different social lifestyles.

Since the bush dog was the most social of the three, she expected it to show the most complex social development; likewise, she thought the  maned wolf would have the least, and the crab-eating fox would be somewhere in between. However, some of her results were rather surprising.

This paper is extremely detailed, so I'll try to sum up the gist of the results. I highly recommend you read through it yourself, though.

Taken together, the results allowed Biben to reach some extremely interesting conclusions.

Given that maned wolves are much larger than crab-eating foxes, it is not surprising that their development lagged behind (larger size = slower growing). But considering the fact that bush dogs are about the same size as crab-eating foxes, it is surprising that their social development was slower.

Biben suggests that this is because the bush dogs are more neotonized than either of the other two species. The extension of a growth and play period is very common in the evolution of highly social species. Bush dogs even have a more paedomorphic appearance, with their rounded heads and short, stocky bodies.

The lack of more complex social behavior in bush dogs was also unexpected, but Biben theorizes that this is because bush dogs experience less conflict with members of their own species than the more solitary and territorial species do. They may need fewer signals to avoid fighting.

Biben also points out that bush dog pups had a higher incidence of submissive behavior (rolling over) which is important in maintaining a lack of aggression in large social groups.***

Finally, the lack of a discernible social hierarchy between pups of any species led Biben to criticize some earlier studies suggesting that canids such as foxes, wolves, and coyotes form dominance hierarchies as pups. She suggests that the reason these studies came up with these results is that they were carried out on captive animals that were removed from their parents or each other for long periods of time, disrupting their normal social development.

While all the litters in this study were also in captivity, they were kept together with both parents. Biben concludes that the normative social structure of canids is simply that pups are submissive to their parents and that they develop no consistent hierarchy within their litter.

Full Text:

Biben, M. (1983). Comparative ontogeny of social behaviour in three South American canids, the maned wolf, crab-eating fox and bush dog: implications for sociality. Animal Behaviour, 31(3), 814-826.

Image credit: Tambako the Jaguar

*In some more recent phylogenies, the bush dog is placed with tribe Canini near the African wild dog. (x)

**Other authors have suggested that the bush dog's high frequency of vocalization and apparent aggression stems from the fact that they have less mobile faces and bodies to communicate with than other canine species. Bush dog vocalizations are quite complex. (x, x)

***Some other highly social canid species, like African wild dogs, have been observed to 'gang up' on a single individual within the group. Biben suggests that this may be a form of submission to the group by the individual that rolls over, but it could also be a form of group hunting play where one member inadvertently becomes the 'victim.' (x)

My cat playing with her new food dispenser ball! She's just starting to get the hang of it.

Many people know that these toys exist for dogs, but they also make them for cats. The benefits of a food dispenser toy include:

The dispenser I'm using is called the "slimcat" and is fairly inexpensive. You can find more food dispenser toys and reviews here.

But there are other ways to make meal time an interactive and busy time for your cat without buying anything. For example, I like to tape toilet paper rolls to something flat and heavy and put food in the bottom so my cat has to pull out the pieces with her paw. This works whether you tape them vertically or horizontally, and you can even make it more challenging by cutting the tubes different lengths and stuffing tissues or cotton in them that the cat has to remove first.

You can also take something like a cribbage board or a plain old pegboard and fill the holes with bolts or pegs with just enough room for your cat to put her paw or tongue in. Then scatter some dry cat food on the board and watch your cat poke and prod away until she can pull the food pieces out.

I shouldn't understate the benefits of making feeding time more interactive for your pet: it's not only fun and challenging for them, but it satisfies food-seeking behaviors that might otherwise be channeled into destroying your house.

Two final notes: One, be very patient. Cats often have a steep learning curve with these toys and it's best to make their challenges very easy and gradually work them up to harder ones. Otherwise you'll just frustrate yourself and your cat.

Second, if you're making your own toys, make sure you're using cat-safe materials.

Have fun!

Happy Hyena