Game: find the snake (Elaphe sp) and the lizard (male Anolis sagrei)
Snake (Elaphe sp.) versus lizard (Anolis sagrei)
Last April and May, I was in Florida… not for holiday but in order to discover the “lizard word” during a field session with Ambika Kamath. For her Ph.D. project in the Losos lab, we collected data on the spatial use of male and female Anolis sagrei to determine the reproductive system of this species. I was surprised when I realized how easy it is to observe these little guys directly in the field! I was really excited to see them mate, fight, display and eat: it was incredible! But the more impressive memory is when I saw a male A. sagrei being eaten by a baby rat snake. I wondered whether this was a really common sight… but I was told I was lucky that day!
The scene happened during a survey, when I saw this unmarked male displaying on a branch… but not on any tree: a tree occupied by a baby rat snake! It was thrilling to see the snake stalking the lizard in a sit-and-wait foraging strategy (as far as a snake can sit…). Even though five long minutes passed where the lizard had time to look around (photo 1), it still jumped on the very branch where the snake was waiting. A great occasion for the predator, who directly started to bite and wrap his body around the lizard whose helpless bites and dewlappings had no effect on the outcome of the fight (photo 2 & video).
After this, I wondered what the mechanisms of predatory detection and avoidance in lizards (including the tail loss ability) could be. Indeed, during predator-prey encounters, there is a transfer of information between them in the form of signals (e.g. auditory, chemical, visual) which may directly modify the outcome of the encounter. Anolis lizards possess a large and complex behavioral repertoire which consists mainly of visual signals (e.g. dewlapping, push-up, head-bobbing) that are used during social interaction, but also in encounters with a predator.
Leal and Rodriguez-Robles in 1997 showed that Anolis cristatellus may rely more on behavioral signals than on flight to avoid predation. It is indeed what I saw: the male lizard displayed to the predator… But I still wonder why this little guy suddenly jumped directly on the snake! Is it possible that he displayed to me and that in front of two potential “predators,” the lizard focused only on the first (or biggest) one that he saw? Apparently, this lizard was more afraid of me than of the snake… wrong choice, I was not going to eat him!
Then, the last day of my field work, I also saw a female cardinal with a big A. sagrei male in her beak… really strange… but I think that the “lizard world” has not finished to surprise me!
Leal, M. & Rodriguez-Robles, J. (1997). Signalling displays during predator-prey interactions in a Puerto Rican anole, Anolis cristatellus. Animal Behaviour 54(5), 1147–54. doi:10.1006/anbe.1997.0572