An Exploration of Play Behaviors in Raven Nestlings

Abstract

-Play is widespread among vertebrates. Some animal groups stand out in their play behaviors in levels of complexity, innovativeness, sociality, and volume. Despite the vast phylogenetic distance between corvids, parrots, great apes, and dolphins, all are usually identified as among the most playful. These groups also have several complex cognitive skills in common. There is growing agreement that play has evolved multiple times under different selective pressures in different lineages. As these groups appear similar in their complex play but are separated by considerable evolutionary distance, the similarity is unlikely to result from homology. Far more probable is that the similarity has arisen from convergent or parallel evolution. It is important to conduct comparative ontogenetic play studies on these groups to learn more about what basic processes underlie complex play and whether such play is, indeed, related to complex cognition. Toward that end, we explored the play behavior of raven nestlings over the last ten days before they fledged. We found high levels of play both in terms of instances initiated and duration. The play behaviors were at level with -or above -maintenance behaviors and flight training. Most of the play was object play, but social object play and apparent play contagion was also recorded. The importance of play in developing young ravens is clear. The reasons might be less clear, however play could underlie both object-related and social development.

Future Thinking: Children But Not Apes Consider Multiple Possibilities

“…The findings from the new study [11] are likely to be of interest to both developmental and comparative researchers and provide a springboard for new research on future thinking. Previous studies of future thinking in apes involved teaching subjects how to use a tool to solve a puzzle, such as using a straw to drink juice [8]. In another room, apes successfully selected this tool and later transported it to the puzzle, but critics argue that this might be driven by past experience with the tool rather than genuine forethought [2].…”

“…In the past decade, considerable progress has been made in identifying genes required for gametophyte development [3,4], but the genetic networks that promote germ cell specification and patterning within male and female gametophytes remain poorly understood [5,6]. One of the bestcharacterized genetic pathways involves the MYB transcription factor DUO1 as a central regulator of cell cycle progression and sperm cell differentiation in Arabidopsis thaliana [7,8]. However, few genes are known to be specifically expressed in the egg [9,10] or to cause misspecification of egg cell fate [11,12].…”

“…Part of the problem is that these studies have fallen short of capturing the uncertain nature of the future: subjects were first trained to expect a certain state of affairs, and then researchers investigated whether or not they could take steps to prepare for this predetermined environment. For example, groups of apes were trained to use a tool to obtain food from a baited apparatus ( Figure 1) that they learned would stay in a given location [7,8]; in another location, the apes successfully chose the right tool to take with them, forgoing an immediate reward [8], and even retaining the tool overnight [7]. Children from the age of 3-4 years also succeed in this kind of task [9].…”

Early evidence for emotional play contagion in juvenile ravens

“…In their study on sub-adult ravens ( Corvus corax ), subjects indeed engaged in various types of play behaviors as a response to a group member’s playful object manipulation. Osvath, Osvath and Bååth ( 2014 ) also described first signs of play contagion in three raven nestlings, but the exploratory character of that study does not allow to disentangle whether it was behavioral or also emotional contagion. In the present study, we followed up on the studies by Osvath and colleagues ( 2014 ) and experimentally tested i) for behavioral or emotional contagion during raven play and ii) whether contagion effects were dependent on age.…”

“…Osvath, Osvath and Bååth ( 2014 ) also described first signs of play contagion in three raven nestlings, but the exploratory character of that study does not allow to disentangle whether it was behavioral or also emotional contagion. In the present study, we followed up on the studies by Osvath and colleagues ( 2014 ) and experimentally tested i) for behavioral or emotional contagion during raven play and ii) whether contagion effects were dependent on age. We thus aimed to i) replicate Osvath and Sima’s findings on emotional contagion (2014) in younger ravens and ii) assess ontogenetic patterns of both forms of contagion, by testing juvenile ravens at two different periods of early development (three- and six-month post-hatching).…”