Category: Natural History Observations Page 31 of 34

A Highly Anecdotal Account of a Most Remarkable Anole

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On June 24, 2011

In Natural History Observations

“You’ve gotta see this!” my fiancé Mark called to me one morning.  He was outside, which could mean only one thing: a wildlife encounter was underway.  Living in a semi-rural neighborhood in Florida, you never knew what you would see, from a mated pair of Sandhill Cranes walking down the street with their young, to Gopher Tortoises excavating burrows in the front yard.

I walked downstairs to the concrete area under our elevated house where Mark was staring at something on the ground.  I looked down to see a frog (Cuban Treefrog) with the tail of an A. carolinensis protruding from its gullet.

“I knew that lizard,” Mark said forlornly.

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Another Anole That Sees With Its Eyes Closed

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On June 23, 2011

In Natural History Observations

Anolis argenteolus is not the only (Cuban) species that has this “window” on the lower eyelid. Anolis lucius also has transparent scales, but if I recall there are 3 in this species. Interestingly, both of these species are to some extent saxicolous or cliff dwelling. So perhaps the sunglasses theory is correct. Protects the eyes from reflection off the white limestone rocks? Attached is an image of this species from the Matanzas Province.

An Anole That Sees With Its Eyes Closed

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On June 23, 2011

In Natural History Observations

The last post makes me recall this weird situation while in Cuba in 2007. Anolis argenteolus seems to have a “fake eye” right at its eyelid. This is mentioned in the species’ descriptions as 2 transparent palpebral scales “as windows”… Looking at some pictures I noticed the scale’s surface being quite reflective and with some iridescence, but it is hard to tell whether they really can see thru it or whether it is just a false eye so when they roost or they close their eyes during the day they are able to show that they still alert. According to Williams & Hecht (1955), these “windows” in the lower eyelids are presumed to act as “sunglasses” in order to reduce light intensity, though I saw the animal doing this even in shady situations. Or they may serve to detect movement while sleeping (Vergner and Polak, 1996).

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Anole Eyespots

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On June 22, 2011

In Natural History Observations

Anoles have served as great model organisms in studies of adaptive radiation and how form and function are molded by selection, but they have also been the center-piece for some of the most interesting (and classic) research on how the brain modulates aggression to determine dominance. For example, work by Cliff Summers and his laboratory (among others) over the years has provided great detail concerning how adrenal catecholamines and glucocorticoids, produced during “stressful” aggressive interactions, interact with serotonergic activity in the hippocampus to determine social rank. These neuroendocrine processes are outwardly expressed, in a sense, by the familiar eyespot seen prominently during male green anole (Anolis carolinensis) interactions. The formation of the eyespot is stimulated by catecholamines, and the latency of eyespot formation is dependent on serotonergic activity, which is influenced by glucocorticoid secretion. Males that develop the eyespot sooner tend to be dominant, and once eyespots have appeared in one combatant, aggression in the rival tends to be inhibited. At least that’s the way it seems to work in A. carolinensis.


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Anole on Anole Violence

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On June 15, 2011

In Natural History Observations, Notes from the Field

Down the hatch. Anolis cybotes eats A. marron. Photo by Luke Mahler.

A few years back I was asked to give a talk to some undergraduate marine biology students studying at the Discovery Bay Marine Lab in Jamaica. I brought a live Jamaican giant anole (A. garmani) to this presentation, and told the students that this species eats just about any other animals it can fit in its mouth – including other anoles. One of the students seemed shocked by this revelation and suggested that “they only eat other anoles in emergencies, right?”  This necessitated a little lecture on nature red in tooth and claw that seemed to leave some of the students on the verge of tears. (Presumably readers of this blog already know that whatever concerns organisms might have about inclusive fitness do not extend to the intra-generic level.)

Although anole on anole predation is a well-known phenomenon, most reports involve adults feeding on much smaller juveniles. In the latest issue of Herpetological Review, Luke Mahler and I report an exception to this generality involving predation by an adult male Anolis cybotes on an adult female Anolis marron.  With a prey SVL ~60% as large as the predator’s (70mm for the predator v. 45mm for the prey) this observation ranks as the highest predator:prey ratio ever reported for anoles. Given that the A. cybotes failed to fully ingest its prey during the 8+ hours we held it captive, we speculate that this event was at, or perhaps even above, this individual’s prey size limit.

Thirsty, Thirsty Anoles

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On May 26, 2011

In Natural History Observations

It’s been very dry here in the Bahamas; we’ve barely seen any rain at all. So, when a few drops splattered mid-afternoon, out came the lizards, slurping up every droplet they could find. In the subsequent 30 minutes, I found six Bahamian green anoles (A. smaragdinus), compared to a rate of 1-2/hour for the rest of the day (this rate, in turn, twice as high as in previous days because it was cloudy and cool).

Ever watched an anole drink when it’s thirsty? This video shows what it looks like.

Land of the Three-Footed Lizards

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On May 23, 2011

In Natural History Observations

 

I noted recently that the brown anoles here in Staniel Cay seem exceptionally skittish, and we don’t know why. Perhaps it’s a coincidence, but we’ve found a trio of three-footed lizards. What’s going on?

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Anoles, American Style

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On May 19, 2011

In Natural History Observations, Notes from the Field

I will admit here that I used to be a little jealous of other anole catchers. This twinge of want was not necessarily due to any perceived greater intellectual merit of the research, nor to collecting successes in terms of sheer numbers of lizards. My envy stemmed from the fact that the stories were exotic, involving international travel to islands in the Caribbean both great and small, where supposedly the anoles practically fall out of the trees and astonish you with their diversity and abundance.

Green anole in Arkansas

I would think to myself how comparatively boring my field work must sound: driving in a blue van with New York plates, weaving across state lines, searching for A. carolinensis, the lone species that lives on the continent —  the Drosophila melanogaster of an otherwise thrillingly diverse genus. Can there be a more boring species than a lizard with the word “green” in its common name? Even the folks I meet while traveling in the field  hint at mundaneness when I tell them what I am looking for: “Where you really need to look is on my aunt’s patio!” Yes sir, I know they often pop up in the begonias, but will they be there when I need them to be (because they never are)? Plus, I have to be in southern Georgia by tomorrow afternoon so I need anoles from this latitude today!

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Not All Lizards Attended That Lesson

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On May 12, 2011

In Natural History Observations

The Lizard Keeper’s Handbook. p 101

In his book, The Lizard Keeper’s Handbook (1997. Advanced Vivarium Stystems, Inc.), Philippe de Vosjoli explains at length how to select prey items of appropriate sizes to feed to pet lizards. I agree 100% with what he wrote. However, I must say that not all lizards apply these rules under natural conditions (I guess they were absent from class on the day that lesson was taught). Here are some photographs I took of brown anoles and Swinhoe’s tree lizards in my study area that preyed on prey items that most certainly did not fall within the ideal prey size categories. 

 1. An Anolis sagrei male with a large caterpillar.

 2. An Anolis sagrei female with the remains of a grasshopper that she had had in her mouth when we captured her.

 3. A Japalura swinhonis female that rushed in to grab a beetle grub that was exposed when we accidentally knocked over a dead betelnut palm (Areca catecha) in our study area.

 4. A Japalura swinhonis male that captured an adult Clanis bilineata in the secondary forest in our study area.

 

And I believe that anyone who works with the brown anole (Anolis sagrei) would agree with me that these lizards can do some truly amazing things, as can be seen from the photos above. One of the most mind-boggling things I have found in the stomach contents of some of these lizards are centipedes. On one occasion I found a 43 mm long Chinese red-headed centipede (Scolopendra subspinipes mutilans) in the stomach of a brown anole male (SVL = 54 mm). Not only was the prey almost as long as the body length of the predator, but centipedes are venomous. It takes guts to take on such a meal!

 

 

 

Brown Anoles Also Eat Butterflies And Moths

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On May 12, 2011

In All Posts, Natural History Observations

Here are three photographs I took of brown anoles preying on lepidopterans. In our diet studies lepidopterans were one of the main prey types, although, as can be expected, the larvae outnumbered the adults as prey. Amazingly, the lizards even ate larvae that had hair, which would cause an irritating burning sensation if it comes in contact with your skin.

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