httpv://www.youtube.com/watch?v=u0bkDhKeeQ4
Thanks to the former student, who sent me the link.
Category: Natural History Observations Page 25 of 34
Photo courtesy Paul Richards
Paul Richards and Kirsten Nicholson found this unusual knight anole while conducting their radio-tracking study on this magnificent species. Richards recalls: “I think we found him on the west edge of the “microbiome” of the Gifford Arboretum. I recall showing it to a well known herpetologist who claimed it was a temporary color change, so we held it overnight. It looked identical in the morning and we released it. I honestly can not remember if we bead tagged it or not (that would be stupid but…). We never saw that individual again, but I also cannot recall how far into the study we were, so our regular searches could have ended soon after. Local lizard fanciers have told me they have seen these color morphs before, so it is apparently somewhat common.”
Non-alphabetically arranged, the ABC islands lie in a row 20-50 miles north of Venezuela with Curaçao sitting in between Aruba 50 miles to the west and Bonaire 30 to the east. Like many small Caribbean islands, each of the islands harbors but a single species of anole. Previous posts have discussed the inhabitant of Aruba and Curaçao, Anolis lineatus. Bonaire’s anole, however, is a beast of an entirely different stripe.
Anolis bonairensis. Photo by Jonathan Losos
What is curious is not the fact that a small island, not too far from other islands, has its own endemic species. Such anole species occur routinely in the Caribbean, such as A. lividus on Montserrat, A. nubilus on redonda, and A. sabanus on Saba. Rather, the oddity of A. bonairensis is its evolutionary heritage.
Young knight anole. Photo from http://www.repticzone.com/forums/Anoles/messages/2236899.html
There’s not a lot in the literature on the size of hatchling anoles, especially the giants, and such toddlers are not well-represented in museum collections. The photos here, easily gleaned from the web, indicate that newborn knight anoles are substantially larger than hatchlings of smaller species. What about other anoles? Does anyone out there know how the size of hatchlings of other large anole species? And how big are the eggs? Pictures, anyone?
Fresh out of the egg. Photo from http://media.photobucket.com/image/recent/RandeMchance/Anolisequestris1dayold.jpg
Anolis lineatus from Curaçao
Several previous posts have discussed the odd case of Anolis lineatus on Curaçao, whose dewlap differs from one side to the other. Rand and Rand reported this in 1967, but the observation was pretty much forgotten until earlier this year, when Matt Brandley and compatriots confirmed the Rands’ claim. Shortly thereafter, Melissa Losos and I travelled to Curaçao as well and observed the same phenomenon, allaying concerns that the Brandley team was covering for the Rands.
But since these posts, many AA readers have no doubt been sleepless at night, pondering the obvious question: what about A. lineatus on Aruba? Do they, too, have mismatched throat fans? Indeed, one could imagine a scenario in which they might not. Asymmetry is a common result of low levels of genetic variation (although there is a lot of quibbling about this in the literature). Curaçao is downstream in an ocean current sense from Aruba. Thus, it could be that the Curaçao population of A. lineatus was founded by one or few Arubians, and thus the resulting founder effect gave rise to the dewlap discordance.
An exciting hypothesis that I am pleased to immediately quash:
Anolis insignis above, Anolis transversalis below. Males on left, females on right. Photos appeared in Lizards in an Evolutionary Tree, photographed by Steve Poe (insignis), Arthur Georges (male transversalis) and Alexis Harrison (female transversalis).
Sexual dimorphism–differences between the sexes–have been greatly studied in anoles, and so has dewlap color and patterning. But little research has been directed to the phenomenon of sexual differences in dewlap color or pattern. Such differences are relatively rare in Caribbean islands, but much more common in mainland species. Why does this occur? Nobody knows. In fact, what female anoles use their dewlaps for has been little studied (another phenomenon, fodder for a future post, is differences in the size of the dewlap between the sexes, which can be quite substantial).
In any case, here’s a sampling of dimorphic dewlaps.
Anolis fitchi (female and male), and Anolis orcesi (female and male)
Photos courtesy Melissa Woolley.
Braving the elements in Charleson.
We all think of anoles as warm weather, tropical beasties, but of course, that’s not entirely the case. Many live at quite high elevations and are active at cool temperatures. For example, this past summer we saw A. orcesi active (as active as it gets) when temperatures were 20 C and below.
In addition, anoles get relatively far north into temperate areas of the United States. One might think that they’d just go to sleep in the winter and not come back out til the spring warmth, but that’s not the case. Faithful contributor Marc Tollis discusses one recent observation over on his own blog, Anolis Tollis.
Frigid temperatures in Boston are making me long for the warm waters of Vieques, PR and the time I was there in October. Truth be told, I work for Jonathan Losos in a mostly administrative role, but even that has turned me into an avid lizard hunter when on vacation in the tropics. I even set a goal for myself – to find and photograph all three species of anoles on the island – except for the one no one has seen in almost 100 years. I trusted that if several professionals have not been able to find A. roosevelti, than my chances were slim (although, I did keep my eyes out for large lizards falling out of trees, just in case). To my absolute delight, the other three species, A. cristatellus, A. pulchellus, and A. stratulus could all be seen running around the manicured garden that surrounded the house I was staying in. We named one “King” and watched him move from palm tree to palm tree, displaying to the other anoles in the vicinity. (I’ve observed many anoles in Ecuador, but had never seen an anole move its tail back and forth before as a display – adorable!)
I watched a spirited courtship between a male and female A. pulchellus in ferns, and spent far too much time trying to get a shot of A. stratulus – particularly one that could always be seen on the wall of the pool house, but would promptly run through the door when I pulled out my camera.
There was even an A. stratulus running around without a front hand. He seemed to move about just fine, though, both through the house and around the vegetation outside. I was proud of my non-biologist friend that worried about him missing “so many sticky toes”. Also entertaining was a fight between two juveniles – unfortunately shot with my cheap telephoto lens, so the quality is poor, but it’s still entertaining: video
Looking forward to a week in the Bahamas in May – another vacation, but I’m sure it too will be filled with anoles.
In September, 2011, Alex Dornburg (Yale), Andy Jones (Yale), Teresa Iglesias (UC Davis), Dan Warren (UT Austin) and I made our yearly pilgrimage to study the marine and herpetological fauna of Curaçao. On the advice of J. Losos, one of our missions this year was to document the dewlap color asymmetry in Anolis lineatus.
In 1967, Stan and Patricia Rand published a paper on the natural history of A. lineatus and noted that:
“The dewlap is large in the male; extended it has a wide border with bright orange skin around a block central spot. The spot is crossed by several widely separated rows of white scales. The border on one side is closely set with yellow or whitish scales, on the other side, the scales are rudimentary and colored like the skin. About half the males have the scales well developed on the right side of the dewlap, about half on the left… one side of the dewlap appears to have a bright orange border, the other side a yellow orange border. The females have a much smaller dewlap, but colored like the males’ and also asymmetrical, though less conspicuously so.”
We braved multiple attacks of push-ups and head bobs and managed to collect and photograph multiple individuals.
Note the large, white scales in the orange field of the dewlaps:
versus the other side of the dewlap which lacks the large, white scales:
The orange vs. yellow-orange difference is a bit subtle and not easily visible in these photos, but it’s there. Like Rand and Rand, we found a roughly equal distribution of individuals with the white scales on the left, and those on the right.
What explains this asymmetry? Are they using the different colors to warn males and attract females?
We are thinking of hypotheses to test during our 2012 trip to the island and we’d appreciate hearing other ideas from other researchers.
Illustrations by A. Seago
As an evolutionary biomechanist that is half in the Losos lab, I naturally dabbled in studying anoles during my first semester. I never presented my research, and have since moved on to other animals, but I thought you might like to see what I found.
Thom’s work on head shape shows a great amount of variation in the jaw length and width among anoles, and we wondered if the shape had an effect on jaw function. I was looking for differences in feeding behavior between the short-snouted Anolis sagrei and the pointy-snouted Anolis carolinensis. I placed a cricket on a leash, put it on a wooden perch inside a plexiglas container, put the lizard on the perch at the other end, and filmed the result.
Here are some videos of one sagrei attack:
sagrei- Front view
And here is a video of a carolinensis:
carolinensis- Side view
Based on my limited dataset, it looks like the sagrei keep their heads low on the perch while they make an attack-dash consisting of 1 chomp. They hold the prey in their mouths for a while before they begin chewing. Carolinensis get very close to the prey, pause, raise their heads up, and stab their jaws downwards without moving their hind legs.
By the way, if you need ideas on how to study anole biomechanics, I’d love to chat!