Category: Natural History Observations Page 25 of 34

Knight anole eating a bird! Photo courtesy of Paul Richards.

In their recent paper on home range of A. equestris, Nicholson and Richards reported on a knight anole consuming a migrating blue-gray gnatcatcher. Here are the full details, in the words of Paul Richards:

“Kirsten Nicholson and I were attempting to resight one of our radio transmitter equipped A. equestris. Resighting transmitted individuals was difficult as they are hard to see even when we have a clear signal. We would regularly spend 15-20min search, and have a 50% change of resighting a transmitted individual (or less, I cannot remember – but we can probably estimate this from our notes). I saw a Blue-gray gnatcatcher land on a branch right in our general search area that was about a 2m diameter zone of the canopy of a small tree at about 3-5m height. I looked away continuing the search and seconds later I heard an alarm call, looked back to the spot and saw the A. equestris in the picture with the bird in its mouth. This A. equestris was unmarked, and I do not recall ever resighting the transmitted individual that we detected in the area. We can check our notes but I think it took at least 20min for this A. equestris to finish eating the gnatcatcher. I recall in using the branch to wipe/swipe its jaw across, one side the the other, repeatedly, to help get the bird in its mouth.”

Read all about what they’re up to here.

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.

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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:

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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.

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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.