One of the brown anole males in the McMann and Paterson study. Photo by Stephen McMann.
Anole Annals readers know otherwise, but many people consider lizards to be simpletons, with nary a thought in their head. But that’s mistaken–it’s salamanders that are the truly stupid ones (sorry for the tangential ad hominem). Lizards have more going on upstairs than people realize. Sure, they’re not the sharpest knife in the drawer, but they’re no dummies, either.
Case in point: lizards are able to recognize and differentiate among other lizards. This conclusion, which has now been demonstrated a number of times, was reinforced by a recent paper by McMann and Paterson in Herpetological Conservation and Biology. They set out to test whether brown anoles react differently when confronted with a neighbor than when confronted with a lizard that lives farther away and that, presumably, the lizard has not interacted with in the past. This is a test of the phenomenon termed “dear enemy,” the idea that neighbors get to know each other and come to a mutual coexistence in which, when they encounter each other, they go through perfunctory displays, but don’ t get all riled up, because they’ve already been through all of that before. The dear enemy phenomenon has been demonstrated previously in a variety of other lizards. Indeed, these authors have demonstrated it before with brown anoles, but that work was conducted in experimental arenas. This time, the authors wanted to see what happened when the research was conducted in nature, in animals’ own territories. To do this, they presented territorial males with another lizard enclosed within a small cage. The stimulus lizard was either the closest next door neighbor or a lizard from a long way away (ca. 200 meters). The results were clearcut: territorial males display less frequently and less aggressively to their neighbors than they did to the strangers. Clearly, the lizards must be able to recognize a neighbor from a non-neighbor, and modulate their behavior accordingly.
Experimental set-up. Stimulus males in the cage on right placed in front of a resident male.
This paper has a number of implications. The most obvious one is that these are complex little animals that have a pretty good grasp of their world. More and more research is working out the cognitive complexity of anoles and other lizards–maybe not Einstein’s, but don’t underestimate them. But there are other, anole-research-specific, lessons. First, to conduct the introduction, the authors presented the stimulus lizard in a small cage. They stated that this approach worked better than presenting a lizard attached by a noose to a long pole, although no data are presented. Many researchers–myself included–have conducted this latter type of study, which is very artificial: the intruding lizard comes swinging out of nowhere and lands in front of the resident like a space alien; to be fair, in this case, the entire cage was swung out of nowhere–using a 2.5 meter long pole–and placed a meter away from the focal male, so maybe there’s no difference in this respect. However, the authors state that the stimulus male behaves more normally when confined to a somewhat spacious cage than when attached by a tether to a pole, which I can readily believe. Bottom line, this seems like a better method than the old swing-’em-in-on-a-noose-pole technique. Second, the paper reinforces my belief that lizards are quite aware of their surroundings. I have to confess that in my youth, there were times in which I caught a lizard to take its photo or take measurements, and then released it at any convenient spot, rather than taking it back home. I now realize that this was a very mean thing to do, and I feel bad about it. The lizards know their homes and their environs, and I now advise everyone to return lizards to the precise spot at which they were captured.
STEPHEN MCMANN AND ANN V. PATERSON (2012). DISPLAY BEHAVIOR OF RESIDENT BROWN ANOLES (ANOLIS SAGREI)DURING CLOSE ENCOUNTERS WITH NEIGHBORS AND NONNEIGHBORS Herpetological Conservation and Biology, 7 (1), 27-37
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Philip Fortman
I see where this explains the difference between two photo essays I posted back in May 2012. The first titled “Two Male Anolis Sagrei Face-Off!” was an intense display without physical contact. The photos in “A 2nd Follow-up To Two Male Anolis Sagrei Face-Off!” involved a different male against one of the first protagonists that was an all out brawl. The first pair were obviously established neighbors while the 2nd was likely a new interloper in the neighborhood.
NOTE: The environment for these confrontations had been completely disrupted. I had torn out about 20 ft. of diseased Ficus hedged and replanted new Silver Buttonwood. This new territory had to be reoccupied and territories redefined by Anolis displaced by the replanting. While my observations had been casual, a systematic methodology could reveal more about territorial behavior by creating a contrived environment like replanting an area.
Joe
After I read this article i thought the same to my self. I used to catch tons of Brown Anoles in a bottle keep them for a few days that release them to a completely different place than there original home.