Brainy Birds Are More Socially Playful Than the Less Endowed
Social play rather than tool use is related to the size of birds' brains.
Posted Dec 01, 2020
Being called a "birdbrain" is a compliment of the highest order deserving of a "thank you very much!"
"Birds engage in three types of play. First, locomotor play, which includes all types of flight-related play such as aerial acrobatics, hanging and flying upside down... Ravens and raptors are the most frequent performers of locomotor play, displaying all sorts of acrobatic acts whilst flying." —Nathan Emery and Nicola Clayton, "Do birds have the capacity for fun?"
"Unambiguous accounts of social play have been recorded from thirteen species of parrots, seven species of corvids, and several hornbills and Eurasian babblers... The adaptive significance of social play in birds thus offers intriguing parallels to similar analyses in mammals." —Judy Diamond and Alan Bond, "A Comparative Analysis of Social Play in Birds"
I'm always looking for interesting news to share with readers, many of whom are "bird-o-philes," as Margot put it. This morning I wasn't let down, and here I want to tell you about a fascinating new essay by world-renowned bird expert Australian ethologist Dr. Gisela Kaplan called "Play behavior, not tool using, relates to brain mass in a sample of birds."1 This landmark piece is available online for free, so here are a few snippets to whet your appetite for more details about this very important project. Having studied various aspects of social and non-social play in mammals and birds and always emphasizing that play is closely tied into the evolution of social behavior, especially increased sociality, I found Gisela's data to be of paramount importance because some researchers are myopically locked into looking at how making and using tools is closely tied into the evolution of brains while ignoring different forms of play and how they're associated with brain size.2
Here's a brief summary of this seminal and detailed comparative research. Gisela begins by recognizing three different types of play: solo or solitary locomotory play when an individual enjoys their own company and engages in activities such as "such as running, skipping, jumping, ducking, rolling, hanging, swinging, dancing and even sliding and snow-romping"; object play when an individual plays with different objects; and social play that occurs when two or more individuals play.
She tested the hypothesis that "large-brained birds play more or, vice versa, those that play more have larger brains, a question that has been asked for some time73,74." To study the relationship between brain mass and play and to exclude the idea that making and using tools is more important than playing, Gisela analyzed brain size and playfulness in different native Australian birds. She also looked at lifespan and learned that players have significantly longer life spans than non-players.
All in all, and after doing the proper controls, Gisela discovered a significant relationship between lifespan and play behavior (her Figure 1), but only for social players and not for non-social players (her Figure 2). She also learned that players had larger brains than non-players (her Figure 3, shown here). She also reports, "Surprisingly, even non-social players (solo or object play) were shown to have significantly larger brains than non-players, but not as large as social players."
Despite her large database, cause and effect are difficult to untangle, so it's still not known if social play evolved because of social brains or whether social play behavior "is causally related to growing a larger brain." More data are needed, but regardless, these relationships are robust and show that play is highly associated with brain enlargement, but tool using is not. She notes, "Since many of the tool using species tested so far also play, this study suggests that false conclusions can be drawn about the connection between tool using and cognitive ability when the silent variable (play behavior) is not taken into account."
Why birds play
There isn't a single reason why other animals play. Various theories have been offered about why animals play—why it has evolved, and what it's good for—and there's no one explanation that fits all examples of animal play. Comparative data show that play is important in social development, physical development, and cognitive development, and also may be training for the unexpected.
Based on an extensive review of available literature, my colleagues Marek Špinka, Ruth Newberry, and I proposed that mammalian play functions to increase the versatility of movements and the ability to recover from sudden shocks, such as the loss of balance and falling over, and to enhance the ability of animals to cope emotionally with unexpected stressful situations. To obtain this "training for the unexpected," we suggested that animals actively seek and create unexpected situations in play and actively put themselves into disadvantageous positions and situations. There's no reason to think that mammals are the only group of animals to do so, and birds who play might also be doing it for the same reason.
Animals may also play because it's fun—for the hell of it because goofing off feels good—during which time they're also benefiting from engaging in the activity itself. If you want animals, human and nonhuman, to do something, make it enjoyable and fun. Playing for fun has psychological and physical benefits. It can relieve stress and also provide exercise in stress-free situations. There are many good reasons why goofing around has evolved. Why not have fun while you can?
Gisela's research makes a significant contribution to comparative studies of animal cognition. It shows that being called a "birdbrain" can be a most-welcomed compliment deserving of a "thank you very much!" and that we need to keep the door open to "surprises" stemming from research on the cognitive and emotional lives of other animals.
There's still a lot to learn about the behavior of other animals, and just when we think we know it all, new research clearly shows we don't. Stay tuned for more on the fascinating lives of birds and other animals with whom we share our magnificent planet. During the current pandemic, new nonhuman neighbors who are "coming home" provide numerous opportunities to learn about animals we rarely see up close and personal and how they adapt to our presence. What a great way to pass the time when our movements are limited and when crankiness may be setting in.
1) The abstract for this essay reads: "Play behaviour and tool using in birds, two well-delineated and amply researched behaviours, have generally been associated with cognitive abilities. In this study, these behaviours were related to relative brain mass in a sample of Australian native birds. Despite suggestive research results so far between cognition and tool using, this study found no significant difference in relative brain mass or in lifespan between tool-using birds and non-tool users. By contrast, in play behaviour, subdivided into social players and non-social players, the results showed statistically very clear differences in relative brain mass between social, non-social and non-players. Social play was associated with both the largest brain mass to body mass ratios and with the longest lifespans. The results show that play behaviour is a crucial variable associated with brain enlargement, not tool using. Since many of the tool using species tested so far also play, this study suggests that false conclusions can be drawn about the connection between tool using and cognitive ability when the silent variable (play behaviour) is not taken into account."
2) Numerous essays and references on play can be seen here.
3) Four different play contexts. (A) Solo play by little corella (Cacatua sanguinea)-holding on to small hanging branch with both feet, the bird swings from side to side as fast and as far as it can, as if on a swing. (B) Social play-wild Australian magpies Gymnorhina tibicen; juveniles at play (identifiable as juveniles by scalloped grey belly feathers) in mutual intimation and ramming attempts conducted close to the ground-can turn into vigorous play-fighting. (C) Aerial play fighting/chasing by juvenile magpies: the aim of the pursuer is to get hold of a tail feather and destabilise the bird in front. (D) Object play of one little corella turning into play-fighting: Note the small dark spot on the left leg of the dominant bird (a desiccated leaf). The other bird had ‘owned’ that leaf but the dominant one tried to snatch it and, in that attempt, subdued the original holder of the leaf. Note that the bird lying on its back has clasped the right foot of the bird above, giving it a hold on the dominant bird. They can wrestle by locking on to the opponent’s foot and then roll around for a wrestling match. Often, the original prize is entirely forgotten and a few seconds or minutes later they feed peacefully next to each other. (Credits: A, B, and C by author; D: Bobbi Marchini).
Bekoff, Marc. "I'm Watching 5 Crows Zooming Here and There, Do They Play?" (Research shows crows and many other birds play just as do many other animals.)
_____. The Family Life of Birds. (An interview with Wenfei Tong, author of a fascinating book about bird behavior.)
_____. Bird Brain: An Exploration of Avian Intelligence. (Dr. Nathan Emery's new book is a gold mine of information and surprises.)
_____. Bird Minds: An Outstanding Book About Australian Natives. (Gisela Kaplan's new book is a must read for researchers and amateur naturalists.)
_____. Goofing Off: Psychological & Physical Benefits of Having Fun. (Playing "for the hell of it," simply because it's fun, is very important to do.)
Kaplan, Gisela. Bird Minds: Cognition and Behaviour of Australian Native Birds. CSIRO Publishing, 2015.
Ortega, Joseph. C. and Marc Bekoff. Avian play: comparative evolutionary and development trends. The Auk 104, 338–341, 1987).
Špinka, Marek, Ruth Newberry, and Marc Bekoff. Mammalian play: training for the unexpected. Quarterly Review of Biology, 76. 141-168, 2001.