All posts by Jonathan Losos

About Jonathan Losos

Professor and Curator of Herpetology at the Museum of Comparative Zoology at Harvard University. I've spent my entire professional career studying anoles and have discovered that the more I learn about anoles, the more I realize I don't know.

Anole Urban Adaptation on the Cover of Evolution

Evolution cover may 2016

Congratulations, Kristin Winchell and co-authors!

And for those of you keeping track, that’s five anoles on the cover of Evolution in the last six years (ending a three-year drought).

Evolution covers may 2016

Incidentally, the paper  continues to attract attention, most recently in the pages of IFL Science:

City Lizards Evolved Stickier Feet, Longer Legs

May 5, 2016 | by Janet Fang

photo credit: Robert Eastman/Shutterstock


Small tropical lizards called anoles have adapted to life in the urban jungle by evolving stickier hands and feet as well as longer arms and legs, according to a recent Evolutionstudy. These help them cling to concrete walls, walk across slippery windows, and perch on metal fences with as much ease as their forest-dwelling cousins.

Urbanization is rapidly increasing around the world, with humans living in nearly two-thirds of the planet’s terrestrial areas. As a result, animals are being confronted with new habitats – from decorative, non-native plants to impervious surfaces and artificial lights. And with these come novel selection pressures. While many wildlife species can survive in cities, relatively little research has been done on whether these populations have adapted (in an evolutionary sense) to their newfound environments.

Crested anoles (Anolis cristatellus) are trunk-ground specialists; they use their long limbs and stocky build to navigate across broad surfaces like tree trunks or the forest floor. The species is native to Puerto Rico, which has been utilized intensively for agricultural cash cops like sugar cane, tobacco, and coffee throughout the 19th and 20th centuries. This has led to massive declines in native wildlife and tree cover. Around the same time, the island underwent major industrialization: 94 percent of the 3.7 million citizens now live in urban areas.

To see if the lizards have adapted to urbanization, a team led by Kristin Winchell from the University of Massachusetts Boston compared the ecology, morphology, and DNA of hundreds of male crested anoles living in three high-density Puerto Rican cities – Mayagüez, Ponce, and San Juan – with anoles living in three subtropical forests nearby.

As predicted, the temperature, humidity, and substrate availability varied a lot between urban sites and their neighboring natural areas. Additionally, urban lizards often used artificial substrates, which were generally broader than the substrates in forests. However, city anoles had longer forelimbs and hindlimbs relative to their body size, and they also had more lamellae – tiny scales on the undersides of their toes that help them “stick” to surfaces.

The team also reared the hatchlings of wild-caught adult pairs from one urban and one natural population: 25 males and 25 females from each of the two populations. They found that the differences between urban and natural wild populations were maintained in their captive-reared offspring – which means these differences are likely genetically based.

Anole Watercolor Available on Etsy


The artist says:

“Lucky Lizard” is an original watercolor painting measuring approximately 8″x10″ and comes with a signed “Certificate of Authenticity” and packed in a clear sleeve with a backing board (unframed). Colors may vary slightly from monitor to monitor.
I use only the finest quality art supplies in my watercolor paintings – 140 lb. CP Arches watercolor paper and Winsor and Newton paints. Also, my art has been certified and accepted by the County of Kauai into their “Kauai Made” program which represents those products made on Kauai, by Kauai people.
The item will ship via USPS First Class anywhere in the world.
The story behind the painting:
This lizard is lucky because he lives in Hawaii! He is a Hawaiian anole and is often called a gecko or a chameleon even though he is more closely related to an iguana. They are found on tropical foliage and really do bring you good luck because they eat the nasty bugs.
I hope you have enjoyed the painting. Have a warm and beautiful day. Once again, Aloha from the Garden Island of Kauai!

New Research on Brains and Hormones of Green Anoles

Photo from

Cornerstone recently reported abstracts from an undergraduate research symposium at the University of Minnesota Mankato. Included in the event were four projects from the laboratory of Rachel Cohen.

Seasonal Effects on Kisspeptin Concentration in the Green Anole Lizard, Anolis carolinensis

Nicholas Booker, Minnesota State University Mankato
Hyejoo Kang, Minnesota State University Mankato


Gonadal steroid hormones are responsible for reproductive behaviors; disruption in production of these hormones is also linked to fertility issues. The hypothalamic-pituitary- gonadal (HPG) axis controls the production of sex steroid hormones, testosterone and estradiol. A peptide, kisspeptin, stimulates this axis by acting on neurons in the hypothalamus. The green anole lizard, Anolis carolinensis, is a seasonally breeding animal that shows drastic changes in behavior and physiology between the breeding and non- breeding seasons. One such change is a large increase in testosterone levels in the breeding season compared to the non-breeding season. These fluctuations in testosterone concentration in green anoles allows for a great opportunity to study the HPG axis. In the current study, we used brain tissue from breeding and non-breeding season green anoles to perform western blot analysis on kisspeptin concentration. Due to the increase in testosterone in the breeding season, we hypothesized that an increase in kisspeptin concentrations will be observed in breeding season compared to the non-breeding season lizards. These results would suggest that kisspeptin does indeed play a role in stimulating the HPG axis and that kisspeptin could potentially be used as a treatment for infertility.


The Effect of Steroid Hormones on Neuronal Size and Number in Two Brain Regions Important for Reproduction

Jaeyoung Son, Minnesota State University Mankato


Steroid hormones, such as testosterone (T) and its metabolites (estradiol, E2, and dihydrotestosterone, DHT), are critical for the production of reproductive behavior. These hormones play a role in neural plasticity, such as changes in neuronal size change and brain region volume. Our study is examining the role of steroid hormones in maintaining the morphology of brain areas involved in reproduction, such as the ventromedial hypothalamus (VMH) and preoptic area (POA). We are using the green anole lizard (Anolis carolinensis) as a model because they are seasonally dimorphic, with more reproductive behaviors and higher steroid hormones in the breeding compared to non-breeding season. We treated our animals with different steroid hormones: T, DHT, E2, and blank capsules as a control. We collected the brains, sectioned the tissue and measured neuron size, number and density in the VMH and POA. We are expecting to find smaller and increased numbers of neurons in the animals treated with steroid hormones compared to the controls. This result would support the idea that steroid hormones are critical for the maintenance of brain areas important for reproduction.


Seasonal Variation in the Dorsolateral and Medial Cortex of Green Anole Lizards

Amber Day, Minnesota State University Mankato
Abdi Abdilahi, Minnesota State University Mankato


The hippocampus is a region of the brain involved in spatial learning and memory, and has been shown to add new neurons in adult animals. Steroid hormones, specifically testosterone

(T) and its metabolites (estradiol, E2, and dihydrotestosterone, DHT), have been shown to play a role in the addition of adult-born neurons to the brain. The green anole lizard, Anolis carolinensis, is a seasonally breeding animal that exhibits seasonally dimorphic behaviors, as well as seasonal anatomical differences in the brain. The pronounced differences between the breeding and non-breeding seasons make this lizard an excellent model for the study of how steroid hormone differences impact the brain. We examined the volume of and addition of new adult-born neurons to the dorsolateral and medial cortex in the lizard, which is analogous to the mammalian hippocampus. We sectioned brain tissue from breeding and non-breeding animals, performed a Nissl stain, and are measuring volume of the regions. We expect that the region will be larger in the breeding season due to the increase of territorial and courtship behaviors. We also treated animals with T, DHT, E2 or nothing as a control and performed an immunohistochemistry to examine how steroid hormones impact neurogenesis. We expect to see significantly more neurogenesis in the dorsolateral and medial cortex of T, DHT, E treated animals in comparison to the untreated group. Our experimental results may provide a greater understanding of the mechanisms that regulate the neural control of reproduction and territorial behaviors.


Amygdala Morphology and Neurogenesis in the Green Anole Lizard

Jadden Roddick, Minnesota State University Mankato
Nicholas Booker, Minnesota State University Mankato
Abodalrahman Algamdy, Minnesota State University Mankato


Steroid hormones and their derivatives play a major role in the reproductive system. One region in the brain that is involved in reproduction is the amygdala. We are examining the relationship between steroid hormones and neuron size, number and neurogenesis in the amygdala of the green anole lizard (Anolis carolinensis). Green anoles are exceptionally good models to examine the neural control of reproductive behaviors because they are seasonally breeding animals and exhibit unique behavioral and physiological differences in the breeding season compared to the non-breeding season. These behavioral differences are likely caused by seasonal changes in circulating steroid hormone levels. For our project, breeding green anole males were gonadectomized and a capsule containing testosterone, estradiol, dihydrotestosterone or left empty was inserted under the anole’s skin. The animals were injected with bromodeoxyuridine (BrdU; a new cell marker) for three days after the treatment. After one month, brains were collected, sectioned, and placed on slides. An immunohistochemistry for BrdU and Hu (neuronal marker) was conducted to examine the presence of new neurons in the amygdala. Alternate sections were Nissl stained and used to count cell number and measure soma size. We expect to see a decrease in neuron number, soma size, and neurogenesis in the animals treated with hormones compared to the animals treated with the blank capsule because we see this pattern in breeding season animals. This work will help provide more insight into the neural control of reproduction.


Advice Needed on Hatching an Anole Egg

Anole egg from

A concerned Anole Annals reader writes in:

My dog just violently chomped  a female alone. Along with her entrails protruding from her body we two eggs. One was small, under-developed the other was the size they are laid. I have at the time done my best to put it into a container and emulate the  same conditions outside ( I live in Florida) with  dirt, leaf litter (small) moisture and heat. I removed the placental outer membrane which would have been separated if she had laid. I feel terrible my young and excitable dog did this. Is there any hope?

Can anyone advise?

Whooping Crane Eats Anolis Lizard

Egret and maybe anole

We’ve come to realize, sadly, that just about everything will eat anoles. Birds are particular culprits and we’ve seen some horrifying examples of egrets downing the little green and brown fellows. Now comes a report that a whooping crane, of all things, will also indulge.

Vladimir Dinets–he of crocodilian behavior fame (check out his awesome book, Dragon Songs )–reported on dietary observations a reintroduced population of cranes in Louisiana. The anolivory represents the first instance of whooping crane predation on a lizard (but not on a squamate, as the photo above attests).


Green and Brown Anoles Living in Harmony on Little Cayman

Photo by Pat Shipman

Photo by Pat Shipman

We’ve often commented on the interactions between the green anole, Anolis carolinensis, and the brown anole, Anolis sagrei. We’ve also had periodic posts from Pat Shipman on Little Cayman, who moonlights as an anthropologist and science and history writer when not watching anoles.

Here’s further evidence that greens and browns can coexist: A. maynardi (a relative of A. carolinensis) and A. sagrei side-by-side, ten feet up on a wall.

Rapid Evolution to Urban Environment in Puerto Rican Anoles

From New Scientist:

Lizard on reddish wall
Clinging on with ease

Kristin Winchell

City living comes with unique challenges. If you’re a lizard, scaling a windowpane without sliding off is one of them. One lizard has already evolved traits to help it do just that.

“Urban areas are just another environment. The animals that live there aren’t somehow immune to natural selection,” says Kristin Winchell of the University of Massachusetts Boston.

Her team compared males of the anole lizard (Anolis cristatellus) in the Puerto Rican cities of Mayagüez, Ponce and San Juan with those in nearby forests.

They found that city lizards regularly clung to objects like walls and windows, proving that they use the full urban environment instead of restricting themselves to wild patches more similar to their forest roots.

Compared with forest-dwellers, city lizards had longer limbs and more lamellae – scale-like structures that help their toes stick to surfaces. These traits probably enable them to stay attached to slippery urban perches. “I chased a lizard that ran straight up a window 30 feet and was out of reach in 15 seconds,” says Winchell. “I couldn’t catch this well-adapted lizard.”

The team also raised urban and forest lizards from the Mayagüez region in the lab and found that differences in limb length and scale number remained, suggesting a genetic basis to the urban lizards’ abilities.

The anole frequently wows scientists with feats of rapid evolution in natural environments. The new finding suggests that this capacity applies to cities as well.

Other urban animals also adapt. We know, for example, that birds alter calls to be heard over city noise and leafcutter ants adapt to elevated temperatures in an urban heat island.

But well-studied examples are rare. “Urban evolution is a really young field,” says Winchell.

Evolutionary biologist Jason Munshi-South of Fordham University in New York agrees. “There aren’t many documented cases of urban evolution yet, but people are going to start looking for them in earnest,” he says.

Munshi-South believes Winchell’s study is an excellent addition to this emerging field. “The next step,” he says, “which I’m excited to see them do, is to identify the genes underlying these adaptive traits.”

Winchell says that, ultimately, understanding urban adaption could help conservation. “Having a grasp on which animals tolerate urbanisation gives us a better idea of which ones we need to focus on when preserving natural habitats,” she says.

Evolution, DOI: 10.1111/evo.12925

Gentle Gorilla Befriends Green Anole

The Dodo provides the full details, but here’s the gist: “I was at the zoo watching the gorilla exhibit [at the San Diego Zoo], and that little lizard came up and just froze when the gorilla started playing with it. He picked it up by the tail a few times, poked at it, but never killed it.”

As Yoel Stuart reported previously in AA‘s pagesAnolis carolinensis has become established at the San Diego Zoo. Who knows which of the zoo’s denizens will be the next to adopt an anole?

Lizard Jumping–Watch It Stick the Landing

This video, shot by Johann Prescher, is of an Anolis lineatus from Curaçao, gracefully jumping from one tree to another. Note, however, what it does just as it lands, pulling up its forebody to contact the trunk with all four legs simultaneously, like a flying squirrel. The mechanics of jumping in anoles have been well-studied, but the mechanics of their landing, not so much. Good research project waiting to be done!

High School Student Seeks Help Understanding Phylogenetics and Pogona: Help Needed

A letter in Anole Annals’ inbox. Can anyone help?:

I am a student from xxx High School in New York. As a science research student interested in phylogeny of squamata, I have come across Bayesian Inference quite a lot. I have spent a lot of time researching bayes theorem and how it relates to phylogeny, but have yet to find an article that makes sense to me as a sophomore in High School. Do have an explanation to bayesian inference and how it used in phylogenetic research? Being interested in phylogenetics, I have looked into researching phylogenetic relationships of Pogona based on molecular data. I have yet to find a taxonomic revision of Pogona, the latest one I found only used morphological data, Taxonomy of Pogona (Reptilia: Lacertilia: Agamidae) by Witten in 1994. Do you think this would be a good topic for me? In addition to selecting genera to study, I have had trouble understanding the methodology that goes into phylogenetic studies. For the most part the methodology resembles collecting DNA data through PCR, then bayesian analysis is run using MrBayes. Can you explain to me the process of choosing primers for use in PCR? Can you explain what and how data is inputted into MrBayes? Would you or anyone you may know possibly be interested in assisting me with my research in the phylogeny of squamates?

Download Skip Lazell’s 1972 Monograph on the Anoles of the Lesser Antilles

From Skip Lazell's 1972 monograph

From Skip Lazell’s 1972 monograph

Like many other biodiversity journals, the contents of the Bulletin of the Museum of Comparative Zoology are available on the Biodiversity Heritage Library. However, the BHL can be somewhat cumbersome to deal with, if not downright counterintuitive. Just today, I downloaded Lazell’s spectacular, classic monograph on the Lesser Antillean anoles, full of detailed descriptions, lovely illustrations (as above) and incisive commentary. Every digital library should have a copy, and so here’s your chance to get one easily, by clicking on this link. But note: the link apparently is only good for 30 days (and someone had to try it twice to get it to work, so be persistent). Also note: it’s a big file, so be patient as it downloads.

Enjoy! And after you look it over, write a nice comment for Skip, AA‘s all-time leading commenter, to read.

Obama’s Historic Visit to Cuba: What about the Anoles?

George Gorman in the field

George Gorman, guru of all things Anolis, writes in:

49 years before Barack Obama’s historic visit to Cuba , I made a historic visit to Cuba but did not visit the Castro brothers, nor was there a baseball game played in my honor. I did, however catch a lot of Anolis,and send a letter to Science about my trip … which was published.”

Read it here.

New 99 Million-Year Old Fossils from Myanmar and the Origin of Chameleons

amber2A recent paper in Science Advances by Daza et al. reported on 12 amber lizard fossils from Myanmar. First author Juan Daza provided an author’s view of the paper two days ago, but I thought I’d add a little more–mostly some cool visuals and links to reporting in the press–here. Particularly notable were a specimen that appears to be on the evolutionary way to becoming a chameleon and gecko with different toepad structures. You can read nice summaries of the articles in the Christian Science Monitor and the BBC.  Anoles even make an appearance in the nifty figure summarizing what we know about fossil amber lizards (more on amber anole fossils).


Another Case of Green Anole – Brown Anole Mating

sagrei carolinensis mating

A common question is whether green anoles (A. carolinensis) and brown anoles (A. sagrei) can interbreed. I am unaware of any hybrids between the two species, and given their long evolutionary separation, it seems unlikely that they could reproduce successfully. Nonetheless, occasional reports of interspecific matings are made, and here’s another.

Mitchell Gazzia posted this photo on his Facebook page, and provided these details:

Took place in late June of 2012 in Melbourne, the Lake Washington area in Brevard County…very close to the intersection of Lake Washington and Turtlemound roads.

Research on How Lizard Brains Work During Aggressive Encounters


Jaramillo uses a cryostat to process sections of lizard brain as part of her research

From the Trinity University newspage:

Leaping Lizards
Tuesday, March 8, 2016

Student researcher Maria Jaramillo lands Sigma Xi grant studying green anole lizards

by Carlos Anchondo ’14

Two male green anole lizards meet in the forest. One lizard has infringed on the territory of the other, who now feels threatened. In a bout of competition, the lizards extend their dewlaps, the flaps of skin beneath their lower jaw, and a faceoff ensues.

Observing this aggressive act, neuroscience major Maria Jaramillo ’17 pondered how the dewlap is processed as a stimulus in the lizards’ brains. She then compared this hostile social behavior with a non-social interaction, like a lizard’s observation of a leaf. How does the lizard’s brain handle each interaction? At what point and why is the brain more active?

To answer these questions, Jaramillo applied for and was awarded a $1,000 grant from Sigma Xi, The Scientific Research Society. The grant money will be used to purchase antibodies, used for immunocytochemistry, as well as other supplies like microscope slides. Jaramillo studies in the lab of biology professor Michele Johnson, a researcher of the evolution of lizard behavior, and collaborated with Johnson during the grant proposal.

“I find the brain very interesting because it controls everything that we do,” Jaramillo says. “I love to study lizards because the wild environments they live in provide all kinds of stimuli, and I want to understand how they process it all.”

For the study, Jaramillo recorded a video of a green anole lizard exposing its dewlap and edited the video, scrambling the pixels of the lizard but maintaining the exact same colors and movements. After removing the social context, Jaramillo analyzed a lizard’s reaction to the modified video in comparison to its reaction to the original. She also tested two lizards together and then played the video without the lizards as an additional control. The lizards were placed in arenas, and Jaramillo observed them using GoPro cameras.

Jaramillo was notified in December 2015 that she had received funding and couldn’t believe the news. She excitedly called Johnson to share her elation, as Jaramillo had been turned down for the grant during the previous application cycle.

“This was a super cool process because Dr. Johnson and I literally built this project together,” Jaramillo says. “I did a lot of the decision making and, even though lizards are not what I am going to study for the rest of my life, it has given me a lot of research experience where I have worked directly with a professor.”

Applying twice for the grant meant that Jaramillo and Johnson received feedback from Sigma Xi evaluators following the initial application. Jaramillo says she was not discouraged after being rejected, but eager to learn how best to improve her chances. A peer tutor for Johnson’s biology class, Jaramillo encourages other not to give up and to “just keep trying.”

From Katy, Texas, Jaramillo plans to pursue medical school after Trinity. Her motivation is to help others with their medical needs and keep them in good health. She says that she has always loved science, and views medicine as a rewarding way to put her interests to good use.

“Health is the thing everyone needs to survive,” Jaramillo says. “For someone who wants to go into medicine, understanding how to conduct research like this is critically important. Studying at Trinity has made me sure that I want to attend medical school and become a doctor.”

Carlos Anchondo is a writer and editor for University Marketing and Communications. He is a 2014 Trinity graduate and can be found on Twitter at @cjanchondo or at