Category: Natural History Observations Page 1 of 34

Anolis sagrei from the Bahamas

A dozen years ago, Jonathan Losos explained in these pages how lizards sometimes end up with multiple tail tips, a phenomenon known as tail furcations. My student Tim Baum and I recently published a review of this phenomenon for all lizards and found that published reports of tail furcations exist for 250 species! For the readers of Anole Annals, I wanted to present a quick review of this phenomenon in the genus Anolis.

Among the many lizard records we located were only ten species of Anolis (4% of the total), slightly below the expected proportion of Anolis out of all lizards (6%). But these anoles do have a nice variety of multi-tails! Overall, they conform to the concept that two tails are the most common occurrence (64% of known anole cases). Two-tailed lizards can be divided into those who have a forked tail that is less than half the tail length (i.e., the extra tail starts nearer the tail’s end), which is known as a bifurcation. The other option is that the additional tail begins closer to the beginning of the tail, and this is known as a duplication. Duplications are relatively rare in Anolis, with only 22% of the two tails originating close to the body.

What is interesting about anoles is that aside from two-tailed lizards, three tails are known from Anolis equestris and A. grahami, and there is even a four-tailed A. sagrei! Most lizard genera stick with the two-tailed version, so anoles have it going on!

Clearly, with well over 400 species of Anolis listed in the Reptile Database (and I don’t want to quibble about genus assignments here), many more species should be out there with furcated tails. Based on our research and literature review, these encounters are serendipities of fieldwork, so keep your eyes open and mobile phone cameras ready – and then publish the new records!

The Anole in the Hole

By Neil Losin

On December 9, 2021

In All Posts, Anole Photographs, Natural History Observations

Anolis cristatellus emerging from tree hole

A male Anolis cristatellus emerging from an abandoned woodpecker hole.

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

Red-bellied Woodpecker excavating tree hole

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

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

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

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

A gray squirrel peeking out of an abandoned woodpecker cavity.

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

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

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

Anolis cristatellus perched outside tree hole

A male Anolis cristatellus perched outside an abandoned woodpecker hole.

Ecomorphology of La Selva Anoles

By Christian Perez

On June 18, 2021

In All Posts, Natural History Observations, New Research, Species Accounts

Ever since the seminal papers by Williams and Rand [1,2], the Anolis radiation across the West Indies has increasingly established itself as an alluring example of ecomorphological convergence. Considering an Anolis community on one island, sympatric species have undergone niche partitioning, whereby each species has evolved particular behavioral, morphological, and ecological traits well-adapted for the microhabitat it occupies. Pop over to another island, and voilà, similar sets of ecomorphs can be found— their resemblance so striking and uncanny.

But the Anolis story isn’t clean cut. Studies of mainland anoles have yielded equivocal findings for whether they also conform to the beautiful patterns observed in the Caribbean. Much baseline data on mainland Anolis communities are needed to determine the extent to which convergence occurs and what factors drive differences in community structure. To partly address this gap, Jonathan Losos, Anthony Herrel, Ambika Kamath, and I recently published a paper describing the ecological morphology of anoles in a lowland tropical rainforest in Costa Rica, at La Selva Biological Station.

Accumulating field observations from four field seasons ranging from 2005 to 2017, we draw from over 1000 observations to characterize the habitat use of eight Anolis species that occur at La Selva. These species include Anolis humilis, Anolis limifrons, Anolis lemurinus, Anolis oxylophus, Anolis capito, Anolis carpenteri, Anolis biporcatus, and Anolis pentaprion, and we opted to devote a brief section to the co-occurring Polychrus gutturosus. Our results revealed overlapping niches and substantial variability in habitat use across many species. Furthermore, the morphologies of A. humilis and A. limifrons were at odds with microhabitat use following the predictions of Caribbean anole ecomorphology. Among the two most abundant species, relative hindlimb length was greater for the more arboreal A. limifrons, whereas it was shorter for the more terrestrial A. humilis.

If mainland and island anoles exhibit divergent ecomorphological patterns, this begs the question of how selective pressures differ between mainland and island habitats to drive these differences. Andrews [3] proposed that predation may more strongly influence Anolis diversification on the mainland, because in comparison to islands, predators are far more abundant, anole population densities are lower, and arthropod prey is plentiful. In contrast, Caribbean anoles are thought to be food limited and there may be stronger selection for niche partitioning. Through examining variation in species’ habitat use relative to the abundance of other co-occurring species at La Selva, our data suggests a low level of interspecific competition for this mainland community, corroborating the hypotheses Andrews set forth.

In recent years, the study of mainland anoles has received more attention. We are in great need of ecological, morphological, and life history trait data for Anolis communities throughout Central and South America to further our understanding of the evolutionary trajectories of mainland and island anoles. So, anole biologists, you can throw out your boats and steer clear of the oceanic divide!

[1] Rand, A. S., and E. E. Williams. 1969. The anoles of La Palma: aspects of their ecological relationships. Breviora 327:1–17.

[2] Williams, E. E. 1972. The origin of faunas. Evolution of lizard congeners in a complex island fauna: a trial analysis. Evolutionary Biology 6: 47–89.

[3] Andrews, R. M. 1979. Evolution of life histories: a comparison of Anolis lizards from matched island and mainland habitats. Breviora 454: 1–51.

Nighttime Day Geckos! You Never Know Where (or When) Phelsuma Are Going to Show up

By James Baxter-Gilbert

On February 23, 2021

In Natural History Observations, Notes from the Field

New natural history note: “Nocturnal foraging and activity by diurnal lizards: Six species of day gecko (Phelsuma spp.) using the night‐light niche”.

A set of observations, recently published in Austral Ecology, noted six different species of day gecko (Phelsuma spp.) using artificial light at night (ALAN) to engage in nocturnal activity (e.g., foraging, courtship, and agonistic behavior). Lizards of this genus are widely believed to be primarily diurnal, however, their propensity to colonize both urban and highly-modified habitats, as well as establish invasive populations within novel landscapes, suggests they are a taxon that is quite flexible and adaptable.

A blue‐tailed day gecko, Phelsuma cepediana, foraging for insects under a fluorescent light in Mauritius. Photo credit J. L. Riley.

Remind you of any other small- to medium-sized adaptable and diverse group of lizards?

Keen readers of the Anole Annals will recall several posts about the effect ALAN can have on anoles, including its impact on physiological stress, metabolism, invasive potential, and reproductive output. With many accounts noting the costs and benefits of shifting diel cycles and daily activity period, but also the general impact light pollution may have. No doubt, there remains a lot of research potential to examine similar questions for the many Phelsuma species across their native and invasive ranges.

Reunion ornate day geckos, Phelsuma inexpectata, engaging in nocturnal activity under a fluorescent light inside a bathroom in Manapany-Les-Bains, Reunion (A,B), including courtship behavior (C). Photos credits C. Baider and F.B.V. Florens.

It is always worth keeping your eyes peeled in the field.

The observations that led to this note came from nine researchers working in various sites, locations, and projects across a number of archipelagos spanning the Indian Ocean and over several years. As with many natural history observations, most of these accounts began with a researcher – who was no doubt occupied with an entirely different task – seeing something out of the ordinary, snapping a picture and jotting down some quick details, and carrying on with their work. A great reminder to never leave home without your trusty notebook; digital or otherwise. Then later on, sometimes much later, this information regarding “something weird you saw” is shared between colleagues, sometimes met with an “oh ya, I saw that too, different species, different location, but the same thing,” and from there, patterns emerge and collaborations bear fruit.

Over the years, Anoles Annals has featured a number of posts related to day geckos, with some keener anolologists expressing the feeling that these colorful, charismatic, and adaptable geckos could be seen as “honorary anoles.” A compliment, surely, the geckos would appreciate and reciprocate toward anoles, if given the chance. Despite their stunning appearance, long history of public awareness, and ability to sell car insurance, there remains a lot of information we do not know about day gecko behavior, biology, and ecology. We hope this natural history note will prompt further research interest into this enigmatic group of lizards.

A Dewlapped Fish!

By Anthony J Geneva

On February 9, 2020

In All Posts, Natural History Observations

Image from Twitter user @OomaTsuna (https://twitter.com/OomaTsuna)

Its clear that possessing a dewlap isn’t a trait unique to anole species. These often colorful, extendable flaps of skin beneath the throats of some female and most male anoles can also be found in other reptiles, and similar structures appear in some mammals and birds. I had always thought that dewlaps were a decidedly tetrapod (and terrestrial) trait. A series of tweets by John Friel, Ichthyologist and Director of the University of Alabama Natural History Museum has shown me just how wrong I was! Behold Triodon macropterus a pufferfish with a most striking dewlap. The thread starts with a retweet of a Japanese language account @OomaTsuna thats post stunning fish photos. Dr. Friel then provides some interesting biological details. This species extends their dewlap as part of their defense display (along with inflating their bodies like other pufferfish species). The flap is extended by a bony protrusion, but instead of deriving from their hyoid as in anoles and other lizards, it’s their pelvic bone that extends the leading edge of skin. See the full twitter thread for all the fishy dewlap detail.

Anolis cusuco as Prey of a Praying Mantis

By Tom Brown

On October 13, 2019

In All Posts, Anole Photographs, Natural History Observations, New Research, Notes from the Field

Predation event between a Praying Mantis (Mantodea: sp.) and a sub-adult female of Anolis cusuco. Photo Credit – George Lonsdale

A natural history note published September 2019 in the journal SAURIA details an unusual observation of anolivory by a Praying Mantis. Specifically, it discusses an event involving the predation of a sub-adult female Anolis (Norops) cusuco.

Anolis cusuco owes its name to its type locality in the cloud-forest of Cusuco National Park, Honduras, and is a species endemic to the country. Few publications exist regarding the natural history of this species and much regarding its ecology, including its potential predators, remain unknown. While a small contribution, this observation describes the first, albeit somewhat unsuspecting predator for Anolis cusuco.

Colour Change in the Gorgetal Scales of an Anole Dewlap

By Tom Brown

On October 8, 2019

In All Posts, Natural History Observations, New Research, Notes from the Field

An adult male *Anolis amplisquamosus* with black gorgetal scales immediately after capture (left); the same individual ~10 min later with white gorgetal scales. Photo Credit – John David Curlis

Anole dewlaps are excellent examples of a “complex signalling system.” They exhibit a staggering diversity of colours and patterns. Each dewlap is species specific and adapted to enable these lizards to communicate, attract mates and guard their territories from rivals or competitors. Generally, the colour of a dewlap (and its gorgetal scales) is considered an unchangeable descriptive trait. This colouration is not only relied upon by scientists looking to identify a species, but also by anoles that co-occur and partition with different species in their select niche.

Therefore, it might be surprising to learn that recent observations prove rapid colour change in anole gorgetal scales is possible. The question is, what implications does this have?

A recent publication in IRCF Reptiles & Amphibians details an observation of Anolis amplisquamosus whereby a male individual upon capture possessed black gorgetal scales that quickly changed to pale yellow. Upon consulting the literature, it seems only one prior documentation of colour change in gorgetal scales was reported (Leenders and Watkins-Colwell, 2003), coincidentally also involving a member of the same species clade.

This recent observation of chromatophoric regulation in anole gorgetal scales may be significant in the wider context of anole biology, in confirming photographically that coloration is not always a fixed descriptive or diagnostic feature — at least among members of the A. crassulus species group. Accordingly, this information suggests that some anoles may have the ability to regulate the colour of their gorgetal scales in the same manner as they regulate dorsal and lateral scale colour.

Because the colour of gorgetal scales is a character often used in species identification, understanding the mechanics and the purpose of such a change is crucial; as well as any implications to display behaviour, communication and anole interactions.

Color Change In the Andean “Chameleon”

By Ivan Beltran

On March 24, 2019

In Natural History Observations, New Research

Anoles are well known for the sharp differences in dewlap colour and size between females and males. However, this is not true for all the species of the genus. Anolis heterodermus is a large arboreal lizard that inhabits shrubs and small trees in the cloudy Andean forests in Colombia and northern Ecuador. Although males are slightly bigger than females, this species has no apparent sexual dimorphism in dewlap size or colouration. Anolis heterodermus is a slow-moving lizard that relies mainly on its body colour pattern to camouflage from predators, thus its common name Andean “chameleon.” Moreover, these lizards have a long prehensile tail which is very useful when moving through thin branches. Interestingly, males curl and swing their tail to their opponents during aggressive encounters.

The body colour pattern is incredibly variable in this species, but all animals have a small patch of bluish scales in the base of the tail. After keeping some of these lizards in captivity, I noticed that the colouration and size of this patch changed dramatically between animals, and even within the same animal over the course of the day. Every time I arrived at the lab in the morning, the patch was small and reddish (Fig. 1A) but after midday, it seemed bigger and with an intense blue colouration (Fig. 1B).

Figure 1: Colour and size variation in the tail patch of Anolis heterodermus. The same male has A) a reddish patch at 06:40 h and B) a bluish patch at 14:47 h.

I thought that the colour and/or size of this tail patch were somehow related to a male’s quality and that could be the reason why males display their tail in the combats. If my hypothesis was correct, males (but not females) would have a larger variation in patch colour and size that is dependant on the time of the day. With the help of some colleagues, I collected males and females of A. heterodermus across the Eastern Cordillera of Colombia. I housed the lizards separately and took photographs (Fig. 1) from each animal every hour between 6:30 to 18:00 h. On each photo, I measured the colour and size of the tail patch. Colour was scored as the ratio of blue vs. red intensities (Blue:Red score), where a larger score indicates bluer scales.

I found that the tail patch of Anolis heterodermus changed from red to blue throughout the day and was generally bluer in males. However, contrary to my hypothesis, the colour change was similar between females and males (Fig. 2). In addition, the coloured patch remained the same size throughout the day in both males and females but was bigger in males.

Figure 2. Diurnal colour change in the tail patch of males and females of Anolis heterodermus. Larger values of the Blue:Red score indicate bluer scales.

Active colour change in lizards often occurs in the context of intraspecific communication (e.g. territorial and courtship behaviour). However, my animals were kept isolated from each other; thus is unlikely that the change in colouration per se is conveying social information. Intriguingly, the highest values of blue colouration for both males and females were reached around midday, which corresponds to the natural peak of activity of the species and possibly to higher body temperatures. In this case, the colour change might be an indicator of animal activity or arousal. This could also explain why the blue colouration disappears at night (personal observation).

Finally, the fact that the patch was significantly bigger and bluer in males compared to females supports the hypothesis that the patch can be relevant in male interactions. It would be interesting to test if the colouration and size of the patch are related to male performance or overall quality.

These are just some of the many questions that still need to be answered about the colour change in the Andean “chameleon,” and this study highlights the importance of observations in the laboratory to identify traits that might be important but difficult to observe in nature.

Original article: Iván Beltrán (2019) Diurnal colour change in a sexually dimorphic trait in the Andean lizard Anolis heterodermus (Squamata: Dactyloidae), Journal of Natural History, 53:1-2, 45-55. DOI: 10.1080/00222933.2019.1572245

Underwater Breathing by a Tropical Lizard

By Lindsey Swierk

On December 20, 2018

In Anole Videos, Natural History Observations, Notes from the Field

Adult water anole (Anolis aquaticus) from Coto Brus, Costa Rica, with an exhaled – and recycled – air bubble. Photo by Lindsey Swierk.

Over the past few years, I’ve been accumulating evidence that the water anole (Anolis aquaticus) might be a tiny scuba diver in the streams of its home in southern Costa Rica. Anolis aquaticus takes to the water as refuge from predators, swimming and often diving underwater for long periods of time – the record at my study site is currently 16 minutes! To enable these crazy-long dives, it’s possible that anoles may have come up with a scuba-tank method of sorts to “breathe” underwater. I’ve compiled a video of what appears to be underwater respiration of a recycled air bubble that clings to the anole’s head. (A few more details about these observations will be in the upcoming March issue of Herpetological Review.) For now, enjoy the video!

Amazing Video of Nest Site Selection in Anolis equestris

By James T. Stroud

On November 17, 2018

In Natural History Observations

Here is an outstanding video of — what looks like — an adult female Cuban knight anole (A. equestris) testing out a potential nest site for egg laying. However, around the 3 minute mark in the video it seems to get spooked and possibly abandons the operation!

What do Anole Annals readers think the lizard is trying to measure when gently prodding the soil with her snout? Substrate firmness? Avenues of easy digging? And when she appears to be licking the substrate? Moisture? Fascinating!

Special thanks to Florida resident Janie Barbato for recording and posting this wonderful video as an addition to her iNaturalist observation of this female.