Author: Neil Losin

The Anole in the Hole

Anolis cristatellus emerging from tree hole

A male Anolis cristatellus emerging from an abandoned woodpecker hole.

Greetings, anole lovers! I wanted to share some recent observations from my Miami backyard. I’ve got a male Anolis cristatellus who’s made his home in an abandoned woodpecker cavity.

Red-bellied Woodpecker excavating tree hole

A Red-bellied Woodpecker excavating a nest cavity in a royal palm tree.

He started using the cavity a few months ago, but the story begins earlier than that. This spring, a pair of red-bellied woodpeckers (Melanerpes carolinus) excavated two cavities in a dead royal palm tree in my yard. When the upper cavity (~4-5m above the ground) attracted the interest of a pair of red-masked parakeets (Psittacara [formerly Aratingaerythrogenys), the woodpeckers shifted their attention to the lower cavity (~2.5m above the ground).

Red-masked Parakeet at tree hole

A Red-masked Parakeet at the entrance of a red-bellied woodpecker nest cavity.

Ultimately the parakeets moved into the upper cavity and it became clear to me that two cavities were actually connected inside the tree, because a parakeet would occasionally enter the upper cavity (which the parakeets had enlarged enough to enter) and, seconds later, peek its head out of the lower cavity (which was too small for the parakeets to enter or exit). The woodpeckers abandoned the site shortly after the parakeets took interest in it, and despite my hopes that *someone* might nest successfully in the cavity, a few weeks later the parakeets abandoned it too.

Gray squirrel peeking out of tree hole

A gray squirrel peeking out of an abandoned woodpecker cavity.

In the late summer / early fall, well after the birds abandoned the cavities, I began seeing a male A. cristatellus around the lower cavity and I wondered if he spent any time inside. The first time I saw him actually emerge from inside the cavity was after a heavy afternoon rain. Subsequently, I saw him close to the cavity entrance at dawn and dusk several times, and I saw him emerge from the cavity early in the morning on at least one occasion. He seems to enter and exit the cavity throughout the day (he can frequently be seen hanging out near the cavity, even during fair weather), but I get the sense that he’s mostly using it as a shelter during the night and during storms.

Over the last several weeks, I’ve also seen a gray squirrel (Sciurus carolinensis) spending time in the same cavity, but surprisingly this hasn’t deterred the anole, who still frequents the cavity as well. Earlier in the fall (during the period when the anole was also using the cavity), I also observed a gecko (Hemidactylus sp.) emerge from the cavity at dusk one night… so the hole is definitely a busy spot, even after being abandoned by its original makers!

I haven’t heard of anoles using nest holes in trees as shelters or night roosts. That being said, whenever I’ve looked for anoles at night, I’ve always looked for more exposed sleeping sites. Have others observed anoles using tree holes for sleeping or for daytime shelters?

Anolis cristatellus perched outside tree hole

A male Anolis cristatellus perched outside an abandoned woodpecker hole.

“Scientist Profiles”: Featuring Anole Researchers on AnoleAnnals.org

Greetings, fellow anole aficionados! One of the new features of Anole Annals is the “Meet The Scientists” page. Thus far, we have populated this page with profiles of each anole researcher featured in our series of short films, The Lizard’s Tale.
 
The purpose of this section of the website, however, is not just to showcase the scientists who appear in the videos – after all, they’ve had their 15 minutes of fame! Our goal for this page is actually to highlight the large, diverse community of researchers around the world who study Anolis lizards… Particularly (although not exclusively) those who contribute to this website!
 
Therefore, we’d like to extend an invitation to all anole researchers, particularly those who contribute to Anole Annals, to share their own profile to be featured on the “Meet The Scientists” page.
 
We use a structured biographic format to ensure consistency among all researchers’ profiles. For your profile, please answer the following questions:
 
1)    Where do you work, and what do you do?
 
2)    What aspects of anole biology do you study, and what have you learned?
 
3)    How and why did you start studying anoles?
 
4)    What do you love most about studying anoles?
 
5)    What is your favorite anole species and why?
 
6)    Where can people learn more about you and follow you online?
(this is where you can provide a URL for a lab website, a personal website, a Twitter and/or Instagram account, etc.)
 
7)    What is your position and affiliation? (E.g. “Assistant Professor of Biology, University of Virginia”)
 
And you’ll need to submit one photograph of yourself… Just one, so choose wisely! You can check out the existing researcher profiles here if you want some inspiration.
 
Please submit your profiles via email to: neil[dot]losin[at]gmail[dot]com. You can attach the text of your profile as a Word document, and include a photo of you (in the field, in the lab, or just a glamorous head shot) as a separate .jpg (please don’t just paste the photo into the Word doc). Images should be a minimum of 350×350 pixels, and you should choose an image that can be cropped to a square format for display on the “Meet The Scientists” page.
 
Please send me all materials by Sunday, Feb. 16. Once I receive everyone’s profiles, I’ll get them up onto the site. Thank you in advance for your help with this!

A. carolinensis

Green Anole

Appearance: Anolis carolinensis is a beautiful green lizard, growing to approximately 8 inches in length, including the tail. Males are larger than females and have proportionally larger heads. The dewlap is usually pink (but can also be grayish or greenish), and is much larger in males than in females. Green anoles can undergo dramatic color changes, from bright green to dull olive, brown, and even yellowish. For this reason, many people in Florida call them “chameleons,” although the green anole’s color-changing ability is modest compared to the true chameleons (Chamaeleonidae) of Africa and Madagascar. 

Ecology and Habitat: The green anole’s body shape is that of a trunk-crown ecomorph. But with no other native anoles sharing its range in the southeastern U.S., it historically ranged from the ground to the treetops, making it more of a habitat generalist than Greater Antillean trunk-crown anoles. Today, it shares much of its range with the brown or festive anole (A. sagrei), a Cuban species introduced to Florida around the turn of the 20th century. Many observers believe that the brown anole is driving a decline in green anole populations. This may be true in some places, but another possibility is that green anoles spend more time in the trees where they coexist with brown anoles. In fact, in areas where these two species coexist, the green anole is usually seen on higher perches than the brown anole (which, as a trunk-ground ecomorph, is typically found within a couple of meters of the ground).

Green anoles are active foragers, moving around trees and shrubs in search of prey. They primarily eat insects and spiders, but will also prey on small vertebrates, consume fruit, and even drink nectar from flowers.

Geographic Range and Biogeography: Anolis carolinensis lives throughout the southeastern U.S., from Florida to North Carolina on the Atlantic coast, and west along the Gulf coast through Texas, all the way to the Rio Grande.

Its closest relative is the Cuban trunk-crown species, A. porcatus. Genetic analyses show that the green anole is probably descended from A. porcatus populations from western Cuba, which probably dispersed over water to Florida. The extent of genetic differences between A. porcatus and A. carolinensis suggest that these two species have evolved independently for at least 6 million years, which means that humans played no role in the original colonization of North America by the ancestors of today’s A. carolinensis.

Finally, the green anole itself has become established in many places outside its native range, probably because of its popularity in the pet trade. Today, you can find A. carolinensis in the Pacific (Hawaii, Guam, Palau, and other islands), the Caribbean (Grand Bahama, Anguilla, Grand Cayman), and in southern Japan.

Research Highlights

Anolis carolinensis is a very well-studied species. In a charming 1876 paper titled “The Florida Chameleon,” the Rev. S. Lockwood recounts detailed observations of his pet green anole, a lizard he called “Nolie,” and concludes that the green anole “…is everything that is commendable; clean, inoffensive, pretty, and wonderfully entertaining; provoking harmless mirth, and stirring up in the thinker the profoundest depths of his philosophy.”

Anolis carolinensis, two subadults in a an aggressive interaction, photographed in Florida. (© Day’s Edge Productions)

Since the late 19th century, biologists have learned a great deal about the green anole, and it has become a model organism for studying many aspects of reptile biology, including the regulation of behavior and reproduction by hormones, social behavior and communication, and the biology of regeneration (because, like most anoles, the green anole can lose and re-grow its tail). In 2011, because of its key role in many subdisciplines of biology, the green anole became the first reptile species to have its entire genome sequenced.

A few recent studies are particularly fascinating. Recall that green anoles coexist with invasive brown anoles (A. sagrei) in parts of their range (see Ecology and Habitat above). In a 2014 study, Yoel Stuart, Todd Campbell, and colleagues studied these two species in Florida by introducing brown anoles to a subset of small, manmade islands that were already inhabited by green anoles. They found that not only did green anoles move to higher perches on the islands they shared with brown anoles, but that over a period of 15 years, the green anoles evolved larger toe pads and more toe pad lamellae (both traits associated with better climbing ability). This may be the best evidence yet that competition between anole species can drive their evolutionary diversification.

Green anoles were in the news again after a 2017 study by Shane Campbell-Staton and colleagues. Studying green anoles in Texas, they measured the lizards’ cold tolerance before and after the winter of 2013-2014, when Texas experienced an abnormally cold “polar vortex” event. Their results show that the extreme cold caused natural selection on the anoles, with southerly populations exhibiting greater cold tolerance after the 2014 polar vortex, on average, than before. Campbell-Staton also used cutting-edge genetic techniques to identify some of the genes that may be involved in cold tolerance.

Species account author: Neil Losin

For more information:
Anolis carolinensis at Animal Diversity Web
Anolis carolinensis at Encyclopedia of Life

Meet the Scientist: Ambika Kamath

Ambika Kamath handling an anole in the field. Photo by Claire Dufour.

Where do you work and what do you do?

I currently work at the Miller Institute for Basic Research in Science at the University of California Berkeley as a postdoctoral fellow. I study a diversity of topics in behavioral and evolutionary ecology, including the collective behavior of social spiders and tent caterpillars, the intersections of behavioral ecology with the social sciences, and the socioecological consequences of individual variation in Anolis lizards. Prior to this, I did my Ph.D. in the Department of Organismic and Evolutionary Biology at Harvard University, and was a postdoc at the University of California Santa Barbara.

What aspects of anole biology do you study, and what have you learned?

I study two aspects of Anolis biology—individual variation in habitat use, and individuals’ movement patterns in the context of mating systems, with the goal of building a nuanced understanding the microevolutionary processes of natural and sexual selection in these animals. I have learned that the actual lives of Anolis lizards—their daily ecological and social interactions—are much more dynamic and complex than previously expected. When viewed in the light of well-established patterns of adaptation and diversification across populations and species of anoles, this messiness becomes particularly fascinating—it prompts us to ask what processes govern the emergence of population-level and species-level patterns over longer timescales from organisms’ daily lives.

How and why did you start studying anoles?

I began studying anoles in 2009, as an undergraduate field assistant for Yoel Stuart and Alexis Harrison. I was initially fascinated by the questions about rapid adaptive evolution that could be asked in anoles, but very soon came to love the animals themselves!

What do you love most about studying anoles?

I love watching anoles! I find their behaviour endlessly entertaining, but also tractable enough to study fruitfully. I also love the challenge of catching them. And finally, anole researchers are a fantastic group of scientists, and I feel lucky to be part of the crew.

What is your favorite anole species?

I’d have to say Anolis sagrei. They’re robust, widespread, and really fun to watch.

Where can people learn more about you and follow you online?

I’m on Twitter at @ambikamath, and my website is ambikamath.wordpress.com.

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