SICB 2018: How does muscle fiber number, size, and behavioral use vary across anole lizards?


Muscle growth and development occur via different physiological mechanisms across the animal kingdom. Variation in behavioral uses of muscle may lead to the evolution of different muscle sizes across animal species. Different-sized muscles may vary in their capacity for strength or frequency of use and larger muscles may develop as the result of possessing higher numbers of muscle fibers, larger muscle fibers, or a combination of the two. Jesus Vega, an undergraduate student with Michele Johnson at Trinity University, was interested in learning how muscle size evolves across anole species by studying the retractor penis magnus (RPM), used to retract the hemipenes back into the tail.

Testing a hypothesis that larger RPM muscles will have more or larger muscle fibers, due to an expected evolutionary trade-off between fiber number and size, Jesus examined copulation behavior data and RPM muscle traits of 24 species of anoles. Behaviorally, there was no correlation found between copulation rate and RPM muscle fiber size or number. Physically however, species that have larger RPM muscles have more RPM fibers, species with larger muscle fibers have RPMs with more fibers, and species with larger bodies have more RPM muscle fibers and larger RPM muscles. These results show that larger muscles evolve due to increased muscle fiber size and number and also suggest that copulation behavior is not associated with muscle size evolution in anoles.

SICB 2018: What is the Relationship between Neuropeptide Y, Corticosterone, and Hunger in the Brown Anole?


Neuropeptide Y (NPY) is a hypothalamic appetite-stimulating regulator of food intake that has been suggested to interact with components of stress response, including the release of the stress hormone corticosterone (CORT). Recent work suggests that NPY can interact directly with the adrenal gland to promote CORT secretion, raising the question of whether NPY can stimulate a stress response and whether NPY requires an active stress response to regulate food intake. This interaction has been examined in mammals but the role of NPY has not been explored in reptiles. To answer questions about the relationship between NPY, stress, and food intake in reptiles, Micaela Castro, a student with H. Bobby Fokidis at Rollins College, performed two manipulative experiments, one in the field, and one in the laboratory, on the brown anole (Anolis sagrei). These experiments utilized injections of NPY and dexamethasone (DEX), an agonist that inhibits CORT secretion, to test the hypotheses that NPY promotes CORT secretion and food intake and that CORT secretion is required for NPY to exert its appetite-stimulating effect.

In the field, adult male brown anoles were captured and injected with varying levels of either NPY, DEX, or saline as a control. An hour after injection, blood was collected and CORT levels were measured. From this study, it was found that NPY injections promoted CORT secretion while DEX injections decreased CORT secretion relative to the saline control. In the laboratory, adult male brown anoles were fasted for either 24 hours or 48 hours, injected with either NPY, DEX, DEX followed by NPY after an hour, or saline as a control, and were observed for differences in food intake. From this study, it was found that DEX injections decreased food intake relative to controls while NPY injections increased food intake relative to controls, but only when anoles were fasted for 48 hours. DEX injections followed by NPY injections resulted in similar food intake to control animals. All together, these results suggest that NPY and CORT are codependent, with NPY capable of stimulating CORT secretion and CORT being required by NPY for it to exert its appetite-stimulating effects.

SICB 2018: Sperm storage and multiple paternity in brown anoles

Sperm storage is widespread in all major reptilian taxa and in combination with multiple mating it could have indirect benefits in polyandrous systems for example by increasing genetic diversity among offspring. Hannah Marshall, a junior majoring in Biomedical Sciences at Auburn University in Tonia Schwartz’s lab, set out to test the utility of microsatellite markers in paternity analysis in a population of brown anoles, Anolis sagrei, in Florida and to assess the extent and pattern of sperm storage from field matings.IMG_20180106_155824

Brown anoles from the field were housed in pairs (control) and in groups of four (2M:2F) and six (3M:3F) in 23 experimental laboratory enclosures. Eggs were collected over one breading season and hatchlings and their candidate parents were genotyped at seven microsatellite loci. The software CERVUS was used to determine the most probable parental pair for each hatchling and to disentangle paternity from experimental males to sperm storage.

Results show that these markers are sufficiently polymorphic to allow paternity assignments with high confidence. With regards to the use of stored sperm, 58% of the eggs produced in the lab were from field matings, which is consistent with previous findings in Anolis sagrei. However, Hannah’s data suggest that these lizards continue to use their stored sperm up to 4 months, longer than previously documented.

These findings are preliminary and Hannah is currently collecting and analyzing more data from these experimental enclosures. Understanding the dynamics of reproductive output in this focal population is valuable for planning further experiments to measure fitness.

SICB 2018: Anole Size Matters to Urban Predators

Urbanization changes many factors, such as temperature and food availability, that influence body size in animals. Last year at SICB, Zach Chejanovski presented on this topic in brown anoles from Miami (Anolis sagrei). He found that predator (curly-tailed lizards) abundance was highly associated with body size in anoles. As predator abundance increases, anole body size increases. Chejanovski, a PhD student at the University of Rhode Island, then formed a new question based on his previous findings: Are larger anoles actually predated on less often than smaller anoles?

Male brown anole showing his dewlap

Male brown anole showing his dewlap. Photo by Renata Brandt

To answer this question, Chejanovski performed a tethered intruder experiment with male brown anoles of variable sizes. For each trial, he tied an anole at the end of a pole and presented the anole to a curly-tailed lizard. He then recorded the amount of time for the predator to get within 20 cm of the anole. Results from a survival analysis show that smaller lizards were attacked more often and more quickly than larger anoles. According to this experiment, larger body size in brown anoles results in less predation from curly-tailed lizards. However, is body size genetically determined?

Curly-tailed lizard

Curly-tailed lizard

Chejanovski then set up  a common garden experiment with female anoles from urban sites with and without curly-tailed lizards. Eggs were collected from these anoles, incubated, and allowed to hatch. Hatchlings were raised in identical lab conditions and measured for body size to calculate growth rate. Male anoles from predator sites grew faster than males from non-predator sites. These results suggest that body size has some genetic control in males. However, female growth rates did not differ between sites. The discrepancy between sexes may be due to different selective pressures, such as sexual selection. This work highlights the importance of body size  in urban environments with predators.


SICB 2018: Does urbanization alter the way anoles move?

Urbanization is a global issue that alters the way many natural populations survive and reproduce. The construction of new developments, housing, and other man-made structures alters the environment available to many species of lizard, and anoles perhaps most famously. Urban anoles in Florida and other parts of the southern United States are a common feature in many cities, why, everybody that attended SICB 2015 in West Palm Beach, Florida remarked that there were anoles on almost every tree! Particularly, the addition of artificial and smooth substrates poses a concern to many species of arboreal lizard that need rough and heterogeneous surfaces in order to climb and run effectively. The differences in structural habitat available to these anoles can in turn affect their morphology, leading to evolutionary changes in body shape and form over time to better adapt to urban lifestyles. Andrew Battles, a PhD student with Jason Kolbe at the University of Rhode Island, recognized this problem and designed a clever experiment to understand just how smoother surfaces impact the running ability of anoles.

Andrew sampled crested anoles from two sites: an urban and a natural site, and used a series of running experiments to understand how the addition of smooth, urban substrates affects the ability of anoles to move. Using two different inclinations (37 and 90 degrees), 2 substrates (smooth and rough), and the running power of 13 crested anoles, they found that anoles exhibit a decrease in speed due to increasing incline, and exhibited slower speeds on a smoother track relative to a rougher one. They also found that stride length decreased on smooth and vertical tracks, and that urban and natural anoles responded similarly to these changes in substrate and incline. They also found that anoles will try to change their gait and increase their stride width due to incline, but not so much on different substrates. Their major take-away was that smoother substrates do decrease lizard sprint performance, which is a fundamental trait for a lizard to survive and reproduce. And while there are no differences between habitat types, the build-up of urbanization over time might lead to evolutionary shifts for crested anoles in urban environments so that they might better adapt and live in cities. Keep up the stellar experiments, Andrew!

SICB 2018: Behavioral and Energetic Influences on Tail Autotomy

As many of us I’m sure know, many lizard species have the ability to lose their tail in order to escape predators or competitors. However, the tail doesn’t grow back as originally lost! The bone, muscle, and fat is replaced by a cartilaginous rod. Lizard species that use their tail in social communication might suffer a severe cost associated with losing their tail because they might lose their ability to communicate information to predators or members of the same species. Amy Payne, a student with Michele Johnson at Trinity University, recognized this issue and used a cross-species comparison to determine just what factors influence tail breakage.

Amy set out to test the hypotheses that species that use their tail in a social context will have lower rates of tail loss, species that use their tail in a predatory context will have higher rates of tail loss, and that species that primarily store fat in their tail will have lower rates of tail loss. They used curly-tail lizards, earless lizards, house geckos, and crested and green anoles in their work and found that curly tail lizards exhibit the greatest tail loss despite using their tails constantly. Earless lizards exhibited the lowest rates of tail loss and they used their tails quite frequently, and anoles had intermediate rates of tail loss based on social use. Tail use in a predatory context was rare for anoles, but quite common for curly tails (that exhibited a higher rate of tail loss) and earless lizards (that exhibited a lower rate of tail loss). They also found no relationship between tail autotomy and energetic storage in the tail. Their major takeaways are that species that use their tail very frequently in communication can exhibit either large or low rates of tail loss, and that there are a lot of intermediate rates of tail loss perhaps due to the multi-faceted role tails play in the evolution, ecology, and behavior of lizards. They are going to follow up this work using bomb calorimetry to more precisely measure species differences in the energy stored in the tail, and increasing the species sampling to incorporate more species (especially more anoles!)


SICB 2018: Copulation rates in anole lizards are correlated with muscle damage

Anolis RPM muscle cross-section. The darkened area in the middle of the muscle shows white blood cell infiltration, which indicates damaged tissue.

Anolis RPM muscle cross-section. The darkened area in the middle of the muscle shows white blood cell infiltration, which indicates damaged tissue.

Many anole biologists have spent a lot of time, money, sweat, and tears collecting behavioral data in the field. These estimates of behavior are very important for understanding how sexual selection operates and how the structures associated with those behaviors evolve, but they are notoriously hard to collect. Kyle Martin and his collaborators decided to try to determine if there might be a better and more accurate proxy for the frequency of specific behavioral displays. As structures are used, so are the muscles that are attached to them. When muscles are used, they incur slight amounts of damage, which causes the recruitment of inflammatory cells that remove debris and allow the native tissue to regenerate. When viewing muscles in cross section, muscle damage manifests as disruptions of normal muscle architecture, notably invaded muscle fibers and regions of densely packed cells. By quantifying this damage in a muscle, researchers may be able to more accurately assess the frequency with which that muscle is used and behaviors are displayed. Anoles have two muscles that attach to the hemipene, which is the intromittent organ used during copulation. Examining damage to the muscle that retracts the hemipene back into the tail (the retractor penis magnus (RPM)) may lead to better estimations of copulation rates in wild populations, which can be difficult to collect for species at low densities, or who mate cryptically.

Martin measured the muscle damage of the RPM for 5-10 males in 27 different species of anoles. This estimate was made by calculating the cross sectional area (CSA) of the RPM and the CSA area of muscle damage of each muscle. He then calculated a ratio of muscle damage (damaged CSA / total CSA) for each RPM and then averaged to give each animal a single value. These species were also observed in the field to measure an observed copulation rate (totaling ~1000 hours of observation). He and his collaborators used phylogenetical generalized least squares regressions to test for a correlation between observed copulation rates and the average ratio of muscle damage across these species.

Positive correlation between observed copulation rates and the average ratio of damage of the RPM for 28 species of anole.

Positive correlation between observed copulation rates and the average ratio of damage of the RPM for 28 species of anole.

They found a significant and strong positive correlation between these estimates, suggesting that examining muscle damage may be an efficient way to estimate behavioral rates. Martin drove home the point that measuring the damage in the RPM of these species took him 2 orders of magnitude less time than estimating copulation rates in the field. This suggests that researchers may be able to more easily estimate behavioral rates of different species, as well as examine individual variation within species. In the future, this group hopes to explore the relationship between muscle damage, copulation rate, and recovery so they can more accurately describe the window of behavior they observe through muscle damage.


SICB 2018: Body Color, Behavior, and Temperature of green anoles

GreenBrownThe color change from a bright, vibrant green to a dull, muddy brown is one of the most characteristic qualities of the green anole (Anolis carolinensis) (I am aware that some dewlap enthusiasts may take issue with this statement). Given the dramatic differences between the colors, Daisy Horr, a Junior in the Johnson Lab at Trinity University in San Antonio, TX, wondered how social behavior and body temperature may influence body color, and whether these relationships differ between males and females.

IMG_6003First, Daisy observed green anole social behavior in Palmetto State Park, TX, and found that males exhibited green body color more frequently than females, and males that performed more pushup and head bob displays also changed colors more frequently (between green and brown). She also found that females were more often green during social interactions.

Because green anoles are ectothermic, more commonly known as cold-blooded, ambient temperature plays an important role in nearly every aspect of their lives. Therefore, there might be a relationship between body color and thermoregulation. Daisy spent a lot of time searching the Trinity University campus for green anoles, and measured body temperatures, the temperatures of the perch on which she found them, and the distance to the nearest alternative perch (a measure of exposure). While she did not find any association between body color and temperature, she did show that males used warmer substrates than females, and that males were typically more exposed (greater distance to the nearest perch). Additionally, she found that males are generally greener than females throughout the day.

Daisy plans to pursue graduate school after she finishes at Trinity University, and we all hope she continues to contribute to anole research! Graduate advisors, you don’t want to miss out on a fabulous researcher!

(This post’s author’s diploma from Trinity University does not affect his assertion that Trinity graduates are among the best minds in biological research.)

SICB 2018 – Are Anoles Adapting to Hot City Environments?

Urbanization, the creation and spread of urban habitats, is increasing across the world. Species that live in these urban habitats are subject to many alterations in their environment, including changes in food, predators, noise, and light among others. One of the most well-known changes associated with cities is the “Urban Heat Island” effect, where city habitats are hotter than surrounding areas due to increases in pavement and other heat-absorbing materials. For lizards such as anoles, living in this hotter environment could be challenging, as increased heat could reduce time available for foraging for food or defending territories, or, in more serious cases, might even lead to death. Shane Campbell-Staton, a postdoctoral researcher at the University of Illinois and the University of Montana, decided to test if anoles were adapting to these hot urban environments, and, if so, what mechanisms were driving this adaptation.


Cities are hotter than the surrounding landscape.

Shane worked with crested anoles (Anolis cristatellus) from four different areas of Puerto Rico that had both urban and nearby natural environments. He and Kristin Winchell, his coauthor, verified that anoles in these urban habitats did indeed experience hotter conditions, and that, as a result, their body temperatures were also higher than anoles from nearby natural areas. In the lab, Shane found that these city anoles were capable of tolerating higher temperatures than their counterparts from natural areas as well. However, after 8 weeks in the lab, anoles from both types of habitats had similar temperature tolerances. Shane also raised offspring from these anoles under common conditions in the lab and found that these offspring had similar temperature tolerances (thermal limits), regardless of whether they came from urban or natural environments. These results show that anoles can have a plastic response to the thermal conditions in their environment, meaning that the differences Shane and Kristin saw in Puerto Rico are induced by an anole’s exposure to temperatures and are not completely determined by their genes.

Crested anoles (Anolis cristatellus) make use of many human-altered habitats.

Crested anoles (Anolis cristatellus) make use of many human-altered habitats. Photo by Andrew Battles.

Shane, however, continued to explore this question: he wanted to know if the ability, or plasticity, of an anole to alter its thermal tolerance in response to exposure to high urban temperatures was due to changes in its genetic structure. In essence, he wanted to know if anoles had evolved a higher responsiveness (or plasticity) in response to inhabiting hotter, city habitats. To get at this, Shane exposed anoles to both hot and normal temperatures in the lab and looked at their levels of gene expression. Using a transcriptomics approach, Shane could see which genes were activated differently when lizards were exposed to temperatures indicative of city and natural habitats. Shane observed differences in variation in the genes in use at these temperatures. He also found higher levels of differentiation between genes involved in thermal adaptation between lizards from city and natural environments. These exciting results show that living in hotter city environments has selected for lizards which are more able to respond to these hot temperatures when they experience them. Shane is continuing to dig deeper into these data to determine which specific genes may have been altered to understand the mechanisms by which lizards are able to alter their heat tolerances. We’re looking forward to seeing these results at a future conference!

On a side note, Shane will be setting up his own lab at UCLA this year, and he’ll be looking for talented graduate students interested in physiology, adaptation, and genomics. Don’t hesitate to look him up!

SICB 2018: Plasticity in thermal physiology is important for adaptation to urban heat islands in Puerto Rican anoles

Effects of urbanization pose major challenges to biological systems globally. One example that impacts the thermal environments of urban areas is the urban heat island effect, where urbanization creates an environment that is hotter than nearby natural areas. In Shane Campbell-Staton’s talk “Temperature-mediated shifts in performance and gene expression between populations of the Puerto Rican crested anole in natural and urban habitats” he sought to investigate divergence in thermal physiology and gene expression between urban and natural populations of anoles in Puerto Rico.

In situ, he investigated whether there were differences in urban and natural microhabitats, lizard thermal tolerance between urban and natural populations, and if there were differences in thermal physiology if this was a plastic or genetic response. He found that urban microhabitats were warmer, and that lizards from urban environments maintained function at higher temperatures when compared to their natural environment counterparts. This increase in thermal tolerance is a plastic response in the urban lizards. He then investigated the transcriptomics to investigate if there is evidence for temperature-mediated selection in urban heat islands, and found that selection on ancestral plasticity may play a role in acclimation to urban heat stressors. Future work includes identify genes involved in this accommodation. Amazing things to come!

SICB 2018: Fighting for food: Does food insecurity influence agonistic in the brown anole?

Leah Elkhoury with her poster at SICB 2018.

Leah Elkhoury, an undergraduate student in the Fokidis Lab at Rollins College, investigated whether access to food would increase agonistic behaviors in the notoriously aggressive brown anole. First, to see if fasting would affect brown anole aggression, she tested wild caught brown anoles by feeding control lizards a regular diet and fasting treatment lizards for either 24, 48, or 72 hours. The treated anoles were then size-matched with a control lizard and placed in an enclosure, where their agonistic displays were recorded and analyzed.  The results of that portion of the experiment indicated that fasting does not increase agonistic behavior.

Next, lizards were separated into two groups: one with predictable feeding schedules, and one with a randomized feeding schedule for one month. This lizards then were tested for aggression in a similar way to the first experiment. The anoles were then sacrificed, and their blood was tested for stress steroid, fat mobilization, and fat deposition. Their brains were then collected and regionally divided to in order to measure stress steroid. Interestingly, lizards in the unpredictable feeding group exhibited more dewlap flashes, one of the brown anole’s agonistic behaviors. They also showed an increase in fat deposition and plasma corticosterone (stress steroid).  Though there were no differences in corticosterone between brain regions.

These exciting results show the “choices” brown anoles make about energy allocation under stress, and Leah plans to continue to ask questions about the link between feeding and aggression. We can’t wait to hear about her work in the future!

SICB 2018: Physiological Traits Predict Behavioral Activity of Female Lizards

One of the most challenging things an organism will do throughout its lifetime is balance its energy budget. Energy is used to grow, develop, reproduce, survive, and how animals allocate that energy will forever be a fascinating question to biologists. If you have more energy, then in theory you should be able to be more active and be a “fitter” individual. For most lizards, excess energy can be represented by fat stores, so if individuals tend to store more energy, then they should be less able to put energy into other reproductive or physiological traits. This was the idea tested by Marzieh Rouzbehani of Trinity University, working in the lab of Michele Johnson.

They studied two anole species: crested and bark anoles (Anolis cristatellus and A. distichus) and found that the two species exhibit different energy-physiology relationships. They found crested anoles with larger eggs had more fat stores, and that crested anoles with larger eggs did not exhibit activity tradeoffs. Bark anoles on the other hand exhibited no relationship between egg mass and fat stores, but found a trend where bark anoles with larger egg masses had lower activity levels. In addition for both species, they found no relationship between hematocrit (the volume percentage of red blood cells in blood) and activity levels, and their work emphasizes the complexity that is species-specific physiological dynamics for female anoles. Different anole species are likely to have different physiological traits influence their behavior and activity in different ways. Fascinating stuff!

SICB 2018: Predicting Climate-Induced Distributional Shifts for Puerto Rican Anoles

Anna Thonis, a Master’s Student in the Lister Lab at Rensselaer Polytechnic Institute, used distributional projection models to predict future ranges of anoles in Puerto Rico. There are ten species of anoles in Puerto Rico, and all of them are predicted to be faced with range shifts in the coming years due to climate change, as Puerto Rico may be faced with both warming and drying out in the future.

Thonis used population occupancy data collected by Lister from 1976-2012 as an input for her models. Using climate models and open source software, Thonis projected anole populations for 2050 and 2070. Based on these models, there will be an average reduction of the most suitable of anole habitats of 29.5% by 2050, and 8 of 10 anole species in Puerto Rico face habitat reduction. In 2070, the models predict and increase in habitat reduction, with a 39.6% reduction in the most suitable habitat and 9 of 10 species of anole facing habitat reduction.

Though these models sound dismal for anoles, Thonis hopes that future work with distributional models can help inform conservation decisions as climate change processes. More detailed models may be able to inform decisions on where protected habitats for anoles should be placed.

SICB 2018: Do back-pattern morphs in female brown anoles differ in morphology, behavior and natural selection?

Sometimes, males and females of the same species differ in traits linked with their ability to survive and reproduce. These differences, called sexual dimorphisms or polymorphisms are quite common in lizards, including anoles! Female brown anoles have a polymorphic back pattern while males are usually of a single pattern. A lot of work has tried to uncover why this back pattern polymorphism exists in nature and what advantages it offers these lizards. Rachana Bhave, a Ph.D. student with Robert Cox at the University of Virginia were interested in determining just how these male and female-like morphs of brown anoles differ in their morphology, behavior, and which traits influence survival.

Using a captive island population in Florida, Bhave et al. captured all of the lizards on the island and measured differences in morphology between the morphs, finding that female-like morphs tend to have higher survival as juveniles but not as adults. These morphs differed in their growth rates but did not experience different selective pressures, indicating perhaps a very complex control regulating the back pattern maintenance in this population. They also found that while female-like morphs tend to display at a higher rate, there weren’t any differences in the morphs probability to attack. They plan to integrate more physiological data such as growth or performance metrics to try and uncover the governing factors responsible for maintaining this back-pattern polymorphism. Awesome stuff to come!

SICB 2018: Environmental Factors Affect Aggression in the Brown Anole

Male-male competition is one of the most widespread phenomena in lizards. Males compete for access to critical food resources, territory space, and female lizards, making a male’s ability to win competitions against other males critical to survive and reproduce. However, how the behavior of a male can vary depending on what social environment he grew up in, the abundance of certain predators or competitors, or the density of other male and female lizards. Therefore, determining what environmental factors influence the behavior of male lizards as they attempt to procure resources necessary to survival and reproduction is a critical question in biology today.

From Virginia Tech, (now a Ph.D. student with Shawn Kuchta at Ohio University) Emily Watts and her collaborators sought to understand what environmental factors influence the behavior of male brown anoles (Anolis sagrei). They used males reared in a common garden from four different populations in the Bahamas to try and determine if genetic or environmental factors influence the aggression differences among males of different populations. Using male-male competition experiments and mirror experiments (where a single male perceives himself as a rival), they tested the hypothesis that males reared in a common garden will not differ in aggressive behavior. They found that aggression varied significantly among populations when using mirror tests, but they found support for their original hypothesis when using male-male competition experiments. This work highlights that aggressive behavior of males is shaped by a multitude of pressures from the environment, to genetics, and ultimately how and where a lizard develops to adulthood. More is to come as they continue to increase the number of their experimental trials with more Anoles!IMG_3929

The Brown Anole: A Proud Texan

From the pages of the San Angelo Standard Times:

Wild About Texas: Brown anole got to Texas as fast as it could

Living in the day and age where memes on social media are the prevailing means of communication does have a FEW benefits. I can almost always count on having a good laugh daily at something someone has posted.

Just the other day, I saw a meme that stated, “I was not born in Texas, but I got here as fast as I could!” As a naturalist, all I could think about when I saw this posted was one particular species of lizard that has found its way here, and that species is the brown anole.

The brown anole (Anolis sagrei) is one of two species of anoles that currently reside in Texas, but this species is not native to this state. First established near Houston in the 1970’s, this species was known only from areas around Houston, San Antonio and Brownsville as late as the turn of the century.

However, now it can be seen in and among most metro areas within an imaginary triangle that pinnacles in the DFW area, east of I-35 and west of I-45. It has only recently been observed (2016) in the Metroplex, and there have not been enough observations to verify whether there is a breeding population there or not. Even more recently, a smattering of individuals had been reported from a nursery in the city limits of Midland and these observations have been verified.

Originally native to the Bahamas and Cuba, this species has been introduced and is thriving in areas outside of Texas as well. It is arguably the most common lizard observed throughout the southern 2/3 of Florida, and it can also be seen throughout the eastern seaboard of Mexico.

The habitats that this invasive lizard prefers are settings in densely vegetated areas. Although occasional specimens are discovered basking and foraging in short shrubs and trees, the vast majority of sightings are of individuals in terrestrial settings. It is the propensity for living among ornamental plants and shrubs that has enabled this species to thrive in the warmer climates outside of its natural range. Therefore, many Brown Anoles are observed living around landscaped human habitations such as houses and even businesses.

The brown anole is among the most plainly colored and yet most intricately patterned lacertilian species in the United States. Unlike the native green anole (which can vary in coloration from green to tan to brown), this anole is always a shade of brown. The scales on the back are small and granular in appearance and texture, and females are often plainly patterned, adorned only with a light stripe that runs lengthwise down the spine. Males on the other hand are patterned with an intricate array of lightly outlined dark wedges and blotches along the spine.

Both species have varying amounts of dark striping that extends behind the eyes. Males have a brightly colored dewlap that, when extended, is dark red. The limbs are long, and are often colored patterned with dark stripes or bands. The head is not nearly as elongated like the green anole and is not noticeably separated from the body, and the tail, which is colored like the back, is about one-half of the 8-inch total length.

Brown anoles, like other lizard species, are “cold-blooded”, or ectothermic. This means that it does not generate heat from the inside of their body, as mammals and birds do, but rather is dependent on outside sources for heating and cooling. It is active during the early mornings and late afternoons from early April to October, and like many other reptile species it avoids the hottest part of the day by resting in shaded areas. However, the fact that it resides primarily in tropical areas, it is often active throughout the year.

This species of lizard is an opportunistic carnivore, feeding primarily on small insects such as moths, butterflies, crickets, grasshoppers, beetles, and the like.

The brown anole is oviparous, which is a fancy way of saying that it lays eggs. During the breeding season, which typically begins in early spring and extends into late summer, males will attempt to attract females by extending his bright red dewlap (a flap of skin underneath the chin) while bobbing his head up and down in a “push-up” manner.

Following successful copulations, the female will begin to lay clutches of a single egg. By laying an egg about every two weeks, a female can lay as many as 12 eggs in a season. These eggs are laid in areas of high humidity, and typically will hatch in about five weeks. The two-inch long hatchlings are smaller imitations of the female, and are capable of fending for themselves immediately.

This lizard species is a gregarious basker and will often allow people to get rather close as it relies upon its coloration for protection. However, once it feels an intruder has approached too close for comfort, it will quickly dart for cover among the leaf litter.

Michael Price is owner of Wild About Texas, an educational company that specializes in venomous animal safety training, environmental consultations and ecotourism. Contact him at

Register Now for the 2018 Anole Symposium

Winning Symposium t-shirt design by Eric-Alain Parker

Winning Symposium t-shirt design by Eric-Alain Parker

Calling all anole aficionados! Spots for the Seventh Anole Symposium on March 17-18, 2018 at the Fairchild Tropical Garden in Miami, Florida are starting to fill up! We have a limited number of spots for attendees and fewer still for presentations. If you have already registered, great! If you haven’t, please do so soon to guarantee your spots. Registering now does not require you to also pay now  – registrants will be contacted in early 2018 to pay the $100 registration fee. Submitting an abstract is not also required at this stage, and can be amended to the registration at a later date.


Notes on the Neblina tepui Anole (Anolis neblininus), Discovered in Brazil

Female  Anolis neblininus .

Female Anolis neblininus .

In November 2017, I had the opportunity to join a team of scientists led by herpetologist Miguel T. Rodrigues (University of São Paulo) in an extraordinary expedition to the Serra da Neblina, a very remote tepui (sandstone table-top mountain) on the Brazil-Venezuela border. The expedition involved the Brazilian Army, several Yanomami guides, and a team of BBC journalists. We collected around 2,500 samples of amphibians, reptiles, birds, small mammals, and plants between 80 and 2,995 m of altitude – among them, at least 10 frog and lizard species new to science!

Neblina peak (2,995 m) as seen from our camp at the Bacia do Gelo ("ice bowl", 1,997 m).

Neblina peak (2,995 m), Brazil’s highest mountain, as seen from our camp in the Bacia do Gelo (“ice basin”) at 1,997 m.

As soon as we got to an elevation of around 2,000 m, we started looking for Anolis neblininus, the Neblina anole. This mysterious lizard was described based on six individuals collected on the Venezuelan portion of the mountain in the 80’s by a team of AMNH-Smithsonian scientists. To our surprise, it took us only a few hours to find one, two, several individuals – the first records of A. neblininus in Brazil!

The Neblina anole seems to be locally abundant, with more than 30 individuals found over a week. Because of their slow movements and cryptic coloration, these lizards are really hard to spot during the day. All but two individuals were found at night, sleeping on thin branches and leaves on the edge of forest patches, at a height of 1-4 meters above the ground. Although we set up 100 pitfall traps in the area to sample herps and small mammals, all of the anoles were found through active search.

Neblina anoles really like to sleep on fern leaves - most individuals were found this way.

Neblina anoles really like to sleep on fern leaves – most individuals were found this way.

To learn a bit about how much Neblina anoles move during the day, we experimented with spooling a few individuals. Based on how much thread they left along their way, it seems that A. neblininus does not move much in a day. Individuals go up and down short trees and bushes, but do not seem to walk on exposed ground. However, the spools that we had – leftovers from a study of larger Enyalius lizards – may have been too awkward for such small anoles to carry.

Spooling lizards is an effective way to learn how much they move and what type of substrate they use. Unfortunately the spools that we had were rather big for these anoles.

Spooling lizards is a simple yet effective way to learn how much they move and what type of substrate they use. Unfortunately, the spools that we had were probably too big for these anoles!

Follow the thread to find the lizard!

Follow the thread to find the lizard!

These montane lizards experience remarkably low temperatures. At night, when temperatures were as low as 6oC, the anoles were unresponsive for long periods after captured, apparently because they were too cold. On consecutive mornings, we followed individuals (spotted on the night before) to check at what time they would become active. To our surprise, the anoles started moving at different times in each day, between 6 and 9:30 am, in an apparent association with how cold it was. It is therefore possible that the onset of activity is given mostly by temperature, as opposed to when the sun comes out.

Male Anolis neblininus. Too cold to go anywhere.

Male Anolis neblininus. Too cold to go anywhere.

One interesting feature of A. neblininus is how variable their coloration is. Some individuals have gray bodies, others green or brown; some have yellow heads. They are also capable of changing their colors a bit. The dewlap is well developed in females, with dark spots on an orange or brown background. Male dewlaps are white, bluish, or yellowish. Neblina anoles have a very cool-looking dorsal crest, more developed in males.

Male (left, center) and female dewlaps.

Male (left, center) and female dewlaps.

Our recent studies of mainland anole lizard evolution and biogeography have found that A. neblininus is closely related to species from montane Atlantic Forest, Andes, and Andean foothills. This pattern may result from a history of cool habitats connecting South American mountains in the past, followed by habitat retraction and extinction in intervening areas. Our expedition to the Neblina revealed additional species that seem to be related with taxa from distant mountains. We are now examining their history based on genetic data to help shed light on the history of the mysterious tepui fauna.