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Figure 1. The skin colors of the Anolis carolinensis. (A) Brown; (B) Green.

We’ve long known that some lizards change color for camouflage or communication, but our new research reveals their skin may also act as a dynamic thermal regulator. Our study published in Animals explores how the green anole (Anolis carolinensis) adjusts its skin color and reflectance in response to short-term temperature changes, offering fresh insights into how ectotherms adapt to their environment.

Figure 2. Skin color changes in the same Anolis carolinensis individual under different ambient temperatures. (A) 20 °C; (B) 30 °C; (C) 40 °C; (D) 24-color checkerboard.

Using controlled lab experiments, we exposed lizards to temperatures ranging from 20°C to 40°C against white and brown backgrounds. We tracked changes in skin color, body temperature, and spectral reflectance. Key discoveries include:

1. Brighter at higher temps: As ambient temperature increased, the lizards’ skin became brighter and less chromatic, shifting from dark green to light green.
2. Optimal at 30°C: At this temperature, the lizards’ body temperature closely matched their environment, suggesting a thermal preference.
3. Reflectance shifts: Skin reflectance in both visible and near-infrared light increased with temperature, indicating a role in managing heat absorption.

This study shows that color change in A. carolinensis is not just for hiding or social signaling. It is also a dynamic form of thermoregulation. In cooler conditions, darker skin likely helps absorb more heat. In warmer conditions, lighter, more reflective skin may help prevent overheating. This ability may be especially important for ectotherms (cold-blooded animals) that rely on external sources to manage their body temperature. As climate change reshapes habitats worldwide, understanding these adaptive strategies could be key to conserving ectotherm populations.

Figure 3. Schematic illustration of Anolis carolinensis skin color and body temperature responses to different ambient temperatures.

Reference:

Hu, J.; Xiong, Y.; Liu, R.; Chen, X.; Liang, A.-P. Skin coloration changes and thermoregulation in Anolis carolinensis across different thermal environments. Animals 2026, 16, 203. https://doi.org/10.3390/ani16020203

Figure 1. Sleeping green anoles on leaves (Photographs by Osamu Sakai).

Sleep is one of the most fundamental states for animals, including humans and wildlife. When people travel to unfamiliar places, one of their first concerns is often where they will sleep that night — at least it is for me. Lizards may face a similar challenge.

Like other diurnal Anolis lizard species, green anoles (Anolis carolinensis) are active during the day and rest at night. Sleeping on vegetation is thought to be a common strategy among arboreal anoles, likely reducing the risk of attacks from ground-dwelling predators. But, how do they sleep in the wild when living in an unfamiliar, non-native environment? Which plant species do they use for beds? Do males and females differ in their choices, or do sleeping habits change across life stages? To address these questions, we investigated the night-time microhabitat use of free-ranging green anoles.

Our focal population is A. carolinensis on the Ogasawara Islands, Japan, located about 1,000 km south of Tokyo. This population originated in North America (the Gulf/Atlantic clade) and has been established on these subtropical islands since the 1960s. During night-time surveys, we observed the green anoles perched on leaves with their eyes closed (Fig. 1). They showed no reaction to flashlight illumination and only a weak response, if any, to gentle tactile stimulation. In short, they appeared to be fast asleep!!

Our survey revealed no sexual differences in sleeping sites with respect to perch height (Mean: males = 256.2 cm; females = 261.7 cm) or the plant species used for beds. In contrast, juveniles slept on much lower vegetation (Mean = 103.0 cm) and used different plant species to adults (Fig. 2).

Figure 2. Ontogenetic niche shifts in the sleeping sites of green anoles. Adults and juveniles used different beds in terms of perch height and variety of plant species. The similarity of the plant species was assessed using Pianka’s niche overlap index

We also found that the characteristics of their sleeping sites were influenced by habitat type. Comparisons between natural forests and human-modified areas suggest that local vegetation has a strong influence on the types of leaves that the green anoles sleep on (Fig. 3). In human-modified habitats, the green anoles were frequently found sleeping on two palm species: the Formosa palm and the golden cane palm. However, at natural forest sites where these palms are absent, the green anoles did NOT rely on particular plant species for their beds.

Figure 3. Comparison of the plant species used by adult lizards in (a) natural vegetation (n = 25) and (b) human-modified environment (n = 98). An asterisk (*) after the plant name represents non-native species on the Ogasawara Islands.

Together, our findings provide a natural history note on A. carolinensis. Notably, the green anoles exhibit an ontogenetic niche shift in sleeping site: as they grow, they change both the perch height of the plants and the species they use for sleeping. Is this niche shift also observed in native green anole populations? Does this pattern have adaptive significance? Further research would be valuable in answering these questions.

Finally, we’d like to discuss the implications for invasion biology. On the Ogasawara Islands, the introduced A. carolinensis has caused severe declines in the native insect fauna, including many endemic species. Improving our understanding of the basic natural history of these animals (i.e., sleep ecology) could contribute to more effective management and control. If you’d like to learn more, the full open-access paper is available in Herpetological Conservation and Biology 20(3): 519–527.

Photo by Miriam Lipsky

And who could blame the little green lady–star fruit are delicious!

Miriam Lipsky of Miami explains:

Photo by Miriam Lipsky

“The star fruits (carambola) are indeed from my yard!  I was picking them to give to a friend, since no one in my family really likes them (Editor’s note: hard as that is to believe!), and when I reached for one of them, this cute anole came with it, then refused to leave the basket.”

Miriam also demonstrated her anole photography chops with this lovely backyard brown anole:

Photo by Miriam Lipsky

Red-bellied woodpecker bashing an anole. Photo by Jacques Rifkind.

Brown anole eating a ringneck snake. Photo by Jacques Rifkind

On December 4, 2025 I observed an Anolis (probably A. sagrei) preying upon an adult or subadult ringneck snake (Diadophis punctatus) in a relictual hardwood hammock forest in Miami, Florida, USA. The lizard was in a vertical head-down position on a narrow tree trunk approximately 2 m above ground, and had the snake’s head in its jaws. Unfortunately, as I photographed the encounter, the anole became disturbed and released the snake, so I was unable to confirm whether the lizard would have been successful at killing and consuming the rather substantial prey item. I examined the snake (approximate length 20 cm) and it appeared not to have suffered damage to its head or neck, and was able to crawl normally. Ringneck snakes are terrestrial / fossorial, so presumably the lizard initially attacked the snake on the ground, then subsequently ascended the tree with its prey. Much has been written about the effects of non-native lizard populations on endemic lizard species through competition and predation. This observation suggests that other endemic vertebrate populations may also be affected by these invasives.

On April 21, 2025, in the same hardwood hammock as the above observation (nature trail at A. D. Barnes Park) I watched a red-bellied woodpecker (Melanerpes carolinus) repeatedly beating an adult unidentified Anolis sp. lizard against the trunk of an oak tree approximately 25 m above the ground. Presumably the woodpecker was attempting to pulp the lizard preparatory to dismembering it or consuming it whole. I observed the bird for 10 minutes before it moved out of view. Melanerpes carolinus was previously recorded feeding on an individual of Anolis carolinensis in South Carolina, so this behavior may not be unusual. I have identified A. carolinensis at Barnes Park on several occasions, and it seems to prefer elevated arboreal habitat (a pattern noted in these pages by Ambika Kamath), by contrast with the more commonly encountered A. sagrei which is abundant on the ground or low in bushes and the bases of trees. Because Melanerpes carolinus is most frequently observed in the canopy, it is at least likely that the woodpecker’s prey in this instance was Anolis carolinensis.

A selection of gecko toepads. Top: Gekko gecko by Peter Geissler, left: Pseudothecadactylus australis by Nick Weiger, right: Oedura monilis by Rishab Pillai.

Like in Anolis lizards, the evolution of adhesive toepads in geckos is often seen as a key innovation, allowing these lizards to exploit vertical environments. Gecko toepads are among the most advanced in the animal kingdom – inspiring research in biomimetics and synthetic adhesion for years. Yet, while the physics of sticking has been studied extensively, the ecology and biogeography have not. Most studies focus on morphology and performance in single species or genera, while large-scale ecological analyses have been rare, something that is considered as a major gap in the literature.

That’s where our project began. The idea originated with Assoc. Prof. Dr. Dennis Rödder and Dr. Jendrian Riedel, and the first task was to take a broad-scale look at toepad variation across all geckos. Following the classification system of Russell and Gamble (2019), we categorized every species into one of four types – absent toepads, basal, distal, and fanlike (Fig. 1) – each morphologically distinct while their functional differences are still not fully understood.

Fig. 1: The four toepad categories according to Russel and Gamble (2019). Ventral view of digit IV from representative species: Left pes of Cyrtodactylus khasiensis (absent), right pes of Gekko smithii (basal), left pes of Ebenavia inunguis (distal), and left pes of Uroplatus ebenaui (fanlike). Illustrations modified from Riedel et al. (2024) and Russell and Gamble (2019).

To explore their evolution and geographic distribution, we combined toepad data with open-access resources on species ranges, phylogeny, climate, and habitat types. Following a range of analyses, we decided on some of the most significant results to create the story-line for our publication.

The first valuable contribution is the classification of toepad types across all species (2230 at the time, excluding the limb-reduced pygopodids), data that is now freely available (Fig. 2). In combination with the phylogeny, we confirmed multiple independent gains of toepads and propose a differential pathway of transitions between pad types.

Fig. 2: Species numbers and family distribution across toepad categories. Includes all recent non-limb-reduced Gekkota species as of September 30 2023 (2230 species)(Kukla et al. 2025, Supplement).

Linking this dataset with biogeography and macro-climate, we also examined how different toepad types are distributed across the globe (Fig. 3) and how they relate to climate and habitat use. Interestingly, we found no sharp climatic boundaries between pad types. Instead, global patterns seem to reflect biogeographic history and the environments where geckos diversified. Nevertheless, we see some habitat associations: adhesive pads tend to show up in structurally complex environments like rocky areas, forests, and even urban settings.

Fig. 3: Global species richness maps for each toepad category: (A) absent, (B) basal, (C) distal, (D) fanlike (Kukla et al. 2025).

Overall, our study provides a global overview of toepad diversity and offers a framework for future, finer-scale studies, moving from global biomes to local microhabitats. We show that gecko diversity isn’t just about sticking to surfaces, it’s about how evolution, ecology, and geography stick together to shape the incredible variety of forms we see today.

If you want to read more, check out our open-access paper:

https://doi.org/10.1111/jbi.70087

Sexual dichromatism in anole dewlaps. 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).

Dewlaps—the extensible throat ornaments of anoles—are classically viewed as male secondary sexual traits used in mate attraction and rival assessment. However, many species exhibit fully developed female dewlaps, and in numerous cases, male and female dewlaps differ in coloration (see some great photos and info in past Anole Annals posts here, here, here, and here! The last post actually inspired Dr. Michael Yuan, senior author on this paper, to work on female dewlaps). What drives this sexual dichromatism?

To address this, we assembled a comparative dataset encompassing 292 Anolis species, documenting dewlap colors in both sexes from the literature, field guides, and community science sources including Anole Annals, iNaturalist, and AnoleKey. We classified dewlap colors based on pigment content, focusing on carotenoids and pterins, which produce red, orange, and yellow hues and often serve as condition-dependent signals. Species were classified as dichromatic if males and females did not share color elements. We integrated these data with measures of body size, sexual size dimorphism, and species co-occurrence, mapped onto the anole phylogeny.

Figure 1. Evolutionary patterns of pigment presence in Anolis dewlaps. (A) Ancestral reconstructions showing how carotenoid- and pterin-based coloration evolved in females (left) and males (right). Pie charts indicate the probability of each pigment state at every node, with tip states shown at the ends of the tree. (B) Proportion of species with each pigment type, separated by dewlap dichromatism categories: female-dewlap absent, monochromatic, and dichromatic.

Our analyses indicate that dewlap coloration is highly evolutionarily labile, with frequent gains, losses, and reversals across the phylogeny. Male and female colors are phylogenetically correlated, suggesting some evolutionary constraint. Crucially, sexual dichromatism appears largely driven by female-specific loss of costly pigments, rather than male pigment evolution. This pattern implies that female dewlap coloration evolves under selective pressures distinct from males, rather than merely reflecting a correlated response to male traits.

We also found evidence consistent with signal partitioning: females were less likely to share dewlap colors or costly pigments with sympatric species, particularly in species-rich communities. In contrast, sexual size dimorphism did not predict dichromatism, suggesting that pleiotropic or androgen-mediated constraints are insufficient to explain female color divergence.

In summary, male dewlap coloration remains relatively constrained, likely due to sexual selection, whereas female dewlaps exhibit greater evolutionary flexibility, often losing costly pigments or diverging in hue to reduce signal interference. These results underscore the role of female-driven evolutionary dynamics in shaping ornamental traits and highlight the importance of considering female signaling in studies of sexual dimorphism.

Future work should investigate the behavioral function of female dewlaps and examine UV reflectance, which is currently poorly characterized but perceptible to anoles. Understanding these components will be critical for elucidating the selective pressures driving dewlap evolution and sexual dichromatism.

You can check out the paper here:

Erin P Westeen, Guinevere O U Wogan, Ian J Wang, Michael L Yuan, Loss of pigments in females is associated with sexual dichromatism in an ornamental trait, Evolution, Volume 79, Issue 7, 1 July 2025, Pages 1299–1309, https://doi.org/10.1093/evolut/qpaf075

And a nice digest written about the article here:

Madelynn M Sinclair, Digest: Sexual dimorphism and signs of selection in the dewlaps of female Anolis lizards, Evolution, Volume 79, Issue 8, August 2025, Pages 1690–1691, https://doi.org/10.1093/evolut/qpaf122

Anolis garmani in a mango tree post-Hurricane Melissa. Photo by Kathryn Miller.

Inbar Maayan writes:

Kathryn Miller.

As you know, Jamaica was very badly hit by Hurricane Melissa. It made landfall in the southwest part of the island and cut across through to the north central coast before continuing northward. Images and videos are circulating that just begin to show the extent of the damage, but everyone says it’s just unfathomable.

Kathryn Miller, one of the excellent Jamaican students who has been on my field team and contributed meaningfully to anole research in Jamaica, was finally able to travel out to help her mother in Santa Cruz, in the parish of St. Elizabeth. This is near Black River, and as you might imagine, sadly the hurricane pretty much flattened this whole area. Kathryn shared with me an anole observation, and I’m submitting it in case folks would like to see a glimmer of the anoles in Jamaica post hurricane.
The photo and video (at bottom) are of an adult male Anolis garmani. Kathryn says “Found him in a fallen mango tree. All the trees in that area were actually either snapped it two or completely uprooted. He’s making the best out of a bad situation I guess. He can’t necessarily go up high anymore. Poor guy”
Anolis garmani is a Jamaican endemic, and like a true Jamaican, this guy is making the best of his situation.”
Kathryn is especially fond of the garmani. She is also a geologist and outstanding artist.
I would like to take this opportunity to encourage people to use the official Jamaican government website for hurricane relief to learn more about the impacts of Melissa and donate what they might be able to.

 Prologue
Nearly 1500 posts.
Over 300 contributors.
Worldwide readership.

Since its origin 15 years ago, Anole Annals has left its mark on anole researchers, reptile enthusiasts, and people curious about why these little tree lizards enchant so many of us. (Just go ahead and admit that’s a fair question!) Many posts on this blog create engaging summaries of the newest anole research, research that spans nearly every discipline of biology. But posts also include anole art, trip reports, and anole history. Anole Annals houses pages with stunning videos and classroom resources, which bring the beauty of anole biology to people outside of our established academic communities. Although the popularity of blogging has declined, the historical impact and reach of Anole Annals is undeniable.

When I made my first Anole Annals post in 2011, I thought that it was a good way to advertise my newest paper and to help establish my name in the field. But I was naïve at the time. 14 years of experience and added maturity have taught me the importance of communicating science to people outside of our immediate academic circles. Over that same timeframe, there has been a rise in anti-science propaganda and misinformation on social media that has eroded the strength of the American science apparatus. With the exception of people working in politically charged areas such as global change or vaccines, most scientists do not have training or experience in confronting attacks on science. We need to change this. We need to do it quickly.

Copied below is a blog post that I wrote to accompany a new Editorial that I published in Integrative and Comparative Biology. I argue that scientists need to step outside of our academic circles into formal and informal settings to rebuild public trust and enthusiasm in science. Our first task is to learn new and effective ways to communicate from professionals who excel at captivating audiences with diverse interests and backgrounds. I repost this here because Anole Annals has had incredible success reaching people from across academic and non-academic circles. I hope my post can bring new energy to Anole Annals and its efforts to disseminate the wonders of anole biology to wide audiences.

How Republican Support for Science Led to My Career as a Biologist

I grew up in a relatively poor, conservative family along the I-90 Rust Belt corridor of central New York in the 1980s and 1990s. My parents often worked multiple jobs to make our minimal ends meet. During the day, my father repaired boilers and pressed shirts at my Uncle John’s dry cleaning business as Rush Limbaugh played at full volume in the background. In the evenings, he worked as a boiler operator for a hospital until his body broke from strains of intense manual labor. My mother worked as a nurse before I was born, but I mainly remember her doing labor and service jobs. I enjoyed my science classes in school,* probably because I liked the outdoors as a kid. But an appreciation of science as a career path was not an inherent part of my upbringing. My parents emphasized that getting an education was my way to a more comfortable life, but they did not direct me to a particular major or career path. As manufacturing opportunities declined across the region, the expectation of attending college was a common sentiment for many kids of my generation from that area. Thus, despite my teenage adrenaline junky desire to become a smokejumper, my parents encouraged me to pursue a college education and sacrificed a great deal to put me through it. I am now a tenured professor at Loyola University Chicago.

Public perspectives on science have changed dramatically over the 80+ years of my parents’ lives. Science rose to prominence in the United States following World War II because of geopolitical competition. Publicly funded innovation and the rapid pace of scientific output were points of bipartisan national pride for the latter half of the 20^th century! The US populace wanted to win the space race. The National Science Foundation’s budget surpassed $1 billion for the first time in 1983, under Republican Ronald Reagan, after his administration recognized that it was in the national interest to compete in a high-technology world. George H.W. Bush led the charge for the Global Change Research Act, which garnered 100-0 support in the Senate. The US population supported the development of new vaccines, antibiotics, and cures for disease, leading to the doubling of the NIH budget between 1998 and 2003. In 1999, Republican firebrand Newt Gingrich stated,

“The highest investment priority in Washington should be to double the federal budget for scientific research. No other federal expenditure would create more jobs and wealth or do more to strengthen our world leadership, protect the environment and promote better health and education for all Americans. For the security of our future, we must make this investment now.”

When my parents encouraged me to pursue education in science, they did not temper their advice with their political leanings. Science was not considered “woke” or a democratic conspiracy in the 1990s. Conservative leaders of the time were advocating for science because of its economic and competitive benefits to the national interest, a message that likely resonated deeply with my parents. They thought that a career in science was a secure path to a life better than the one they were living. Full stop.

Fast forward to 2025, and I am left wondering, “What the hell happened to this nation’s respect and support for science?” * Many Americans now question whether a college education is “worth it,” even though advanced education was the catalyst for the success of many people from my generation. Given the current political environment, it is difficult for me to imagine that my family would encourage my pursuit of a career in science today. In fact, my career has been a point of contention for us since 2016. It’s difficult for me to see this new generation of kids capable of undergoing the same socioeconomic transformation that led me to my current career.

This long introduction frames my motivation for the recent Editorial I wrote for Integrative and Comparative Biology. Since January 2025, the United States has witnessed the rapid acceleration of anti-science rhetoric and direct attacks on the scientific enterprise, following the blueprint laid out by the 900-page Project 2025. These attacks are more energized, pervasive, and combative than anything I have witnessed during my career. I feel an urgency to get more scientists engaged in public discourse and to update our educational systems to help students recognize propaganda and refute misinformation. The goal of my Editorial was to 1) contrast the ways that scientists communicate with the strategies that more communication-based professions use, and 2) to lower barriers for scientists to purposefully experiment with new communication strategies. The infographic to the right highlights the main points of the Editorial.

15 years ago, multiple organizations called for scientists to engage with the public and the policymaking process.

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