Do animals play?

Play behavior is, in humans, quite obviously something we grow up with and bring into adulthood with us. The games change as we grow, but the concept is exactly the same.  Play is crucially important in our social development as children; in other words, “plays well with others” is an important component of a person’s functioning in society. Physical play hones strength, agility, balance, etc. Mental play builds, and helps maintain, neural connections in our brain. And don’t forget that play is just plain fun, and that fun is relaxing, which is crucial to maintaining health. You get it. From your own experience, you already know everything I’ve said here, so you already know that play is important, multifunctional, and comes in a very wide variety of forms (some of which are not obvious!).  

But do animals play? Do all animals play, or only some types or species? This topic has been debated, sometimes controversially, since at least the 1800s. Charles Darwin made references to observed behaviors among animals that he interpreted as playing. Because of its diverse, and sometimes subtle nature, play can be difficult to define, which means it also can be difficult to identify with certainty based on animal observations. A century ago, some scientists claimed many animals lack the cognitive skills to be involved in play. Some species, they argued, are too cognitively simple to engage in play. Other scientists focused on purpose, and were frustrated by the fact that sometimes they could not connect seemingly frivolous activities observed with anything related to survival and reproduction – in other words, a basis for natural selection.  

A broadly accepted definition of play describes it as repetitive, seemingly non-functional behaviors that differ structurally, contextually, or developmentally from more adaptive counterparts, initiated in relaxed or low-stress settings. Whew! You might want to read that sentence a couple of times. It comes to us courtesy of legendary animal behaviorist Dr. Gordon Burghardt, a now-retired but still-active professor at the University of Tennessee. He further breaks play down into five component criteria:  

1. Incomplete functionality and unrelated to immediate survival 
2. Voluntary, spontaneous, and/or pleasurable/rewarding 
3. Different than typical maintenance behaviors, as it is incomplete, exaggerated, or precocious 
4. Repetitive but not stereotypic because of variability 
5. Initiated in situations when the animal is fed, healthy, and free of stress and intense competition.  

Dr. Robert Fagen has organized play into three contexts:  

1. Object/predatory play occurs when the animal manipulates and explores inanimate objects 
2.  Locomotor/rotational play comprises bodily movements such as running, spinning, or jumping.  
3. Social play involves interactions between two or more animals, not necessarily conspecific, for instance chasing or mock fighting.  

So, playing with a ball is object play, climbing on playground equipment is locomotor play, and chasing your friends is social play. These are not mutually exclusive and often occur simultaneously.  

But don’t be fooled by ready definitions and criteria! Play in animals can be difficult to demonstrate scientifically, and it can be deceptively easy for a good scientist to fall victim to bias, mischaracterization, and anthropomorphism. This is not an easy field of research. 

Next time you are at Zoo Atlanta, watch the youngest gorillas for a while. You will see play behavior within minutes, and it is clear that play behavior builds social skills necessary for survival in gorilla social groups. Watch younger goats as they seem to purposefully trip themselves up and fall over all by themselves. My guess is that it does not hurt, that it is fun (human kids in a park will do the same thing), and scientists have suggested that it builds balance and coordination skills in a species that evolved jumping across rocks on sheer cliff faces. Indeed, learning to recover immediately from a non-perfect landing can save your life if you are a wild goat.  

Play behavior in mammals has been accepted as a real phenomenon for a long time, but some behaviorists argued that animals that they prejudicially assumed to be “lesser” in terms of cognitive skills do not, indeed cannot, play. Reptiles and amphibians are common examples of this scientific prejudice. “They are too simple to engage in something as esoteric as play” is a common argument. Critics have argued that play behavior in animals is restricted to the realm of mammals, and maybe birds, and particularly social mammals like most primates and many carnivore and hoofstock species. In fact, early proponents of play in animals (e.g., Dr. Burghardt) were actually shunned and mocked by some of their colleagues for their heretical ideas of play in reptiles or invertebrates. To resolve this, enter zoos and enter Dr. Burghardt! 

Zoos are perfect situations for evaluating play in animals. The general behavioral profile and habits of individual animals often are known, and this is because animal-care professionals often are among the very best observers of animal behavior. The animals are accustomed to being observed, so they don’t tend to change their behaviors (e.g., freeze still, or run away) at the sight of a human. We have constant and unobscured views of the animals under every condition. And we can manipulate things such as giving them a ball, or giving them the choice among four different balls and a cube.  

Focusing on animals in zoos and aquariums, Dr. Burghardt and his students forged new ground in animal play and have inspired a generation of behaviorists such that we now have play unequivocally documented in a wide range of animals as diverse as spiders, octopus, fish, and, yes, reptiles! (Teaser: My lab has a paper to be published soon documenting play in our turtles at the Zoo!) I encourage you to re-watch the truly captivating movie My Octopus Teacher and argue with me that the octopus and the diver are not mutually engaging in social play. What is interesting is that this is heterospecific play, in other words individuals of two different species coming together to play. If that sounds bizarre and unlikely to you, just bring a tennis ball to a dog park and see how long it takes for another species to attempt to engage in play with you! 

In his classic 1981 book Animal Play Behavior (referenced below), Robert Fagan identified the first known published suggestions of play in reptiles. He found a 1946 report of object play in a zoo-housed Komodo dragon (visit the Zoo at Halloween and watch our dragon, Rinca, play with his holiday pumpkin!) and a 1977 report of an American alligator repeatedly snapping at the drops from a dripping faucet. Since Burghardt pioneered the field of animal play in reptiles, there have been multiple descriptions of social play, object play, and locomotor play in various crocodilians and turtles. But there have been very few reports from lizards (all object play), and arguably only one report in snakes (a gopher snake engaged in locomotor play with a length of cord). These examples are all listed in an article I co-authored (referenced below, and available on my ResearcGate.org page). This leaves me wondering if tuataras play? I also wonder if we are just missing something in how we observe, or more likely how we interpret our observations in snakes and lizards? Surely there are more examples out there. 

My guess is that the “breakthrough” observations of play in snakes, at least social play, are going to come from Project RattleCam (https://rattlecam.org/), which is an innovative endeavor led by my friends Dr. Emily Taylor and Dr. Scott Boback. They have mounted remote cameras in rattlesnake dens in California and Colorado and film them 24/7. They are already documenting amazing social behaviors of which we were unaware, and I bet they will find social play soon. You can be trained as an observer to help them monitor and collect data from the livestreams. I highly recommend that you consider joining this popular citizen-science program. Maybe it will be you who discovers novel play behaviors in snakes! 

References and Suggested Readings: 

• Burghardt, G. M. (2005). The Genesis of Animal Play: Testing the Limits. MIT Press. 
• Burghardt, G. M. (2011). Defining and recognizing play. In A. D. Pellegrini (Ed.), The Oxford Handbook of the Development of Play (pp. 9–18). Oxford University Press. 
• Burghardt, G. M. (2014). A brief glimpse at the long evolutionary history of play. Animal Behavior and Cognition, 2(2), 90. https://doi.org/10.12966/abc.05.01.2014 
• Burghardt, G. M. (2015). Play in fishes, frogs and reptiles. Current Biology, 25(1), R9–R10. https://doi.org/10.1016/j.cub.2014.10.027 
• Dinets, V. (2023). Play behavior in ectothermic vertebrates. Neuroscience & Biobehavioral  Reviews, 155, 105428. 
• Fagen, R. (1981). Animal Play Behavior. Oxford University Press. 
• Mendelson III, J. R., G. W. Schuett, and D. P. Lawson. 2019. Krogh’s principle and the importance of modern zoo collections to academic research. Pp. 586–617 In A. Kaufman, M. Bashaw, and T. Maple (Eds.), Scientific Foundations of Zoos and Aquariums: Their Role in Conservation and Research. Cambridge University Press.