Category: Natural History Observations Page 9 of 34

Anolis agassizi. Photo by Margarita Ramos.

Pat Shipman’s recent observations on a brown anole displaying at a fluttering orange flag, and her question about whether anyone has seen an anole paying particular attention to the color orange brings to mind the famous Chuckles experiment.

In the early 1970’s, a Smithsonian-led expedition visited remote Malpelo Island in the Pacific Ocean off the coast of Colombia. To make a long story short, the researchers noted that the endemic A. agassizi, a very interesting species in its own right, seemed to have a thing for orange objects. To test this hypothesis, they turned to Chuckles, the hard jelly candy that comes in five colors, one of which is orange (and which, fortuitously, they had a package available on the ship on which they were based, there being no land accommodations on Malpelo).

Bottom line: the anoles do, indeed, prefer orange and yellow. Read all about it in this snippet, extracted from the article:

Rand, A.S., G.C. Gorman, and W.M. Rand. 1975. Natural history, behavior, and ecology of
Anolis agassizi. Smithsonian Contributions in Zoology 174:27–38.

I describe the experiment and an abortive attempt to follow up on it in Lizards in an Evolutionary Tree (footnote 189, p.146):

No discussion of anole frugivory and feeding behavior is complete without mention of the famous Chuckles® experiment. On an expedition to remote Malpelo Island off the coast of Colombia, Rand et al. (1975) noted that the native anole of the island, A. agassizi, was attracted to the orange cap of a bottle of suntan lotion and to the orange packaging for Kodak film, and would come running from great distances and in great numbers when half of an orange was placed on the ground. The intrepid biologists wondered whether these anoles had a particular predisposition to the color orange. Fortunately, the expedition was outfitted with packages of Chuckles®—billed as “America’s most popular jelly candy” in a 1949 advertisement—which conveniently contain candies in five colors: orange, yellow, red, green, and black. By placing various combinations of these sweets on the ground, the authors found that anoles are most attracted to orange and yellow candies, and least attracted to black ones.

But the story does not end there. In an effort to extend this research program to additional species, a graduate student in my laboratory tested a captive A. grahami with differently colored Starbursts®, a non-jellied candy that also comes in different colors (Chuckles® may not have been available in the local vending machine). Unfortunately, this experiment was stymied by other members of the lab, who removed lizard-bite sized pieces from the candies, thus briefly convincing the experimentalist that he was on to a major discovery.

A previous discussion on this blog has raised the following question: in which situations is a lizard most likely to lose its tail? Common wisdom has it that tails are most frequently lost in the avoidance of predators, and observational evidence backs this up, at least in the case of anoles–no AA reader has observed tail loss in a male-male aggressive interaction. But what about other lizards?

In Sitana ponticeriana, an agamid lizard that I often post about on this blog, a couple of observations point to the likelihood of male-male competition as a driver of tail loss. Tail loss is not uncommon–in the locality I have sampled best, 13.5% of lizards have lost their tails. Males are about 1.7 times as likely to lose their tails as females (16.5% of males vs. 9.6% of females). Further, lizard predators aren’t too common in this locality–fewer than 30 individuals of potential lizard predator species were spotted or heard in over two months of sampling, and no predation attempts were observed.

But more excitingly, I had the chance to observe firsthand the loss of a tail during a male-male fight this summer! The resident lizard had lost much of his tail prior to the fight, a measly 5.4 cm remaining. The intruder, however, had an almost complete tail. Here is a rather blurred photo of the two males facing each other:

Read More

AA reader Angel Sosa sends the attached photo and writes: ‘During monitoring of amphibians and reptiles in Cerro Azul region of Alto Chagres, Panama, I photographed three moth flies on the back of Anolis lionotus. The moth flies had bellies full of blood, which is clearly seen in the photograph. It’s the first time I have seen this group of arthropods feeding on a reptile. This is an endemic area of leishmaniasis, but little is known of the ecology of parasites in reptiles and their medical importance.”

Anolis barkeri. Photo by J. Losos

As part of its ongoing studies of Central and South American anoles, Team Mainland—fresh off successful field work in Colombia and Venezuela earlier this year, traveled to the Veracruz, Mexico to sample that state’s anole fauna. Joined by Anne-Claire Fabre, Victor Jiménez, and Ramón Martínez, Team Mainland worked at the fabled Estación de Biología Tropical Los Tuxtlas, home to eight or nine (depending on which paper you read) species of anoles. The goal of the trip was to characterize the ecology, behavior, and morphology of the species residing at the station. Although all anoles are interesting in their own right, as we know, not all anoles are created equal. And, indeed, there was one special species we had our heart set on seeing: the large aquatic anole, Anolis barkeri.

Anolis barkeri. Photo by J. Losos

Anolis barkeri. Photo by Victor Jimenez.

And lo and behold, we saw them! Aided by Bob Powell’s advice to visit his old field site, a lovely stream located several kilometers from the station, we spent several days observing the antics of these gorgeous anoles, the largest of the mainland aquatics. And by antics, I mean primarily sitting around doing nothing, though they did flash their gorgeous red dewlaps occasionally (alas, not caught by camera, but several times on video—stay tuned once they get processed). Actually, they were sometimes quite active, running rapidly from one place to another. Like other mainland aquatics, these guys hang out right next to streams, and when threatened will sometimes jump in. They don’t go swimming away, though, at least not in our observations (which agree with others); rather, they immediately go to the nearest water-land interface and hang out, hoping they have not been detected.

Our trip occurred in early August, at the end of both the reproductive and dry seasons. We were told that it had been a particularly dry dry season, which may explain some of the observations. For example, A lemurins is supposed to be very common, but we didn’t see a one. Also, males of two other common species, A. sericeus and A. rodriguezi, were few and far between. This was surprising, but perhaps these—like many mainland species—are primarily annual, that is, with a lifespan averaging less than a year.  Perhaps the males, spent by their exertion, are all dead, explaining why we saw so few of them. That was a classic hypothesis borne of field observations, but the Malice of Nature did not intervene to refute it. A number of people suggested that A. barkeri is only found in shaded streams; in the open, it is pushed out by basilisks. “Find a basilisk,” we were told, “and you won’t find A. barkeri.” For the record, we did find several small basilisks along the stream, though only in open, sunny spots in the otherwise well-shaded watercourse. The A. barkeri were found on logs and rocks, always near the water. They didn’t impress me as brilliant swimmers, but could immediately climb onto rocks—very good graspers, with long arms and sharp claws.

I was particularly curious to learn more about A. sericeus.

Read More