It’s been a while since we’ve looked at an anole from South America, so why not go all the way over to an an anole that is probably at the highest elevation an anole species has ever been found: Anolis heterodermus, the Flat Andes anole!
Anolis heterodermus lizards are arboreal and can be found on montane elevations in Colombia and Ecuador at about 2,600 m (8,530 ft). As you can guess, living at an such an elevation should be too cold for a lizard, but the Flat Andes anole is ok with this. They have been found to have wider preferred and body temperature ranges than expected for anoles and have adapted to take advantage of the limited hours of sun that the area gets (Méndez-Galeano & Calderón-Espinosa, 2017).
These anoles are large rich green to olive lizards with males being slightly larger than females at 85.4mm and 85mm respectively. They have wide banding on their bodies and both males and females have a patch on their tails that have been observed to change from red to blue throughout the day. This patch is larger in males (Beltrán, 2019) and is another sign of sexual dimorphism in this species. Their dewlaps are pink striped.
More on Anolis heterodermus from the pages of Anole Annalshere.
Semi-aquatic Anolis lizards have some of the most fascinating ecologies, colour patterns, and behavioural strategies in the genus (though I may be biased). Twelve of these neotropical streamside specialists are distributed across much of mainland Latin America and on the two largest islands of the Caribbean. All are rarely found more than a few meters from a stream and some have been observed to consume semi-aquatic prey (or, in the case of A. vermiculatus, even small fish and freshwater crustaceans).
Range map of all 12 semi-aquatic anole species
A riparian lifestyle is also responsible for the signature move that unites all species of semi-aquatics—escape dives! As anyone who has encountered one of these lizards in the wild can attest, semi-aquatics will readily dive underwater when approached. They can stay down for awhile too—up to 18 minutes by my count (Mexico’s A. barkeri currently holds the record). Diving anoles have attracted the attention of tropical biologists for more than half a century now (e.g., Robinson 1962; Brandon et al. 1966; Campbell 1973; González Bermúdez and Rodríguez-Schettino 1982; Birt et al. 2001; Leal et al. 2002; Henderson and Powell 2009; Muñoz et al. 2015; Herrmann 2017) and this work has begun to fill out our natural history knowledge of these enigmatic lizards. However, understandably, most work to date has focused on what these lizards are doing when they’re not in the water. And, as it turns out, there’s a lot to learn if we look below the surface…
In 2009, while studying Anolis eugenegrahami, an endangered semi-aquatic anole from Haiti, Luke Mahler and Rich Glor noticed that an individual they had just released into a clear, shallow stream proceeded to repeatedly exhale and re-inhale an air bubble as it clung to the rocky bottom. Luke and Rich had to move to their next site later that day, so weren’t able to learn more. Sadly, a follow-up field season was cancelled in the aftermath of the 2010 Haiti earthquake.
Years later, when I started my MSc thesis on aquatic anoles in at the University of Toronto, Luke shared this observation with me. When an anole does something once, another anole somewhere else usually does it convergently, so we couldn’t help but wonder whether aquatic anole species elsewhere also exhibited this apparent “rebreathing” behavior. So, when I was planning my first field season in Costa Rica, on a hunch, we purchased an oxygen microsensor, and I set out to establish whether this intriguing behaviour occurred in any other semi-aquatic anoles.
Costa Rica field team, 2017
Colombia field team, 2018
Mexico field team & friends, 2018
The aquatic anoles did not disappoint! During my Master’s, along with an amazing team of colleagues, I visited stream habitats in Costa Rica, Colombia, and Mexico, studying A. oxylophus, A. aquaticus, A. maculigula, and A. barkeri along with the non-aquatic anoles we were able to find at each site. I found that each of these species routinely performed the same behaviour that Luke and Rich had observed in A. eugenegrahami! We named this phenomenon “rebreathing” after the SCUBA apparatus. All of the semi-aquatics we observed performed rebreathing extensively during experimental submersions and are from five phylogenetically distinct lineages, showing a pattern of remarkable behavioural convergence!
As I was conducting these experiments, “rebreathing” was independently discovered in Anolis aquaticus by Lindsey Swierk (see image below, and Lindsey’s 2018 AA post). Lindsey is the world authority on Costa Rica’s diving anoles, and has reams of firsthand knowledge about their ecology and behavior. So we did the obvious thing when we found out about her observation – we invited her to join our project. We managed to deliver our oxygen sensor to Lindsey in Costa Rica via a colleague with overlapping travel plans, and she helped fill out our oxygen use data set for the Costa Rican diving anole species. In addition, Luke tested Anolis lynchi in Ecuador, and various non-aquatic species during fieldwork there and elsewhere (Dominican Republic, Jamaica) to help round out the data set.
A diving A. aquaticus performing rebreathing (Photo: Lindsey Swierk)
Speaking of non-aquatic anoles, what role do they play in this story? An interesting one, as it turns out. Rebreathing clearly seemed fascinating, but one possibility was that it was relatively ubiquitous and that all anoles would rebreathe if you submerged them. To find out, we did just that, carefully dunking aquatic and non-aquatic anoles alike in aquaria or buckets at our field sites.
What we discovered is that most non-aquatic anole species are indeed capable of basic rebreathing, but for the most part, they don’t rebreathe anything like the semi-aquatics do. If they rebreathed at all, non-aquatic species tended to do so only occasionally and irregularly (usually only one or a few re-inhalations). Since semi-aquatic anoles performed rebreathing extensively and consistently, while non-aquatics were capable of the basic components of rebreathing, but did not rebreathe regularly, we think consistent rebreathing may have evolved when natural selection found a new utility for a trait that all anoles possess—hydrophobic skin. The hydrophobicity of anoles’ scales is likely what enables the air bubble to adhere to the diving anoles’ heads (and thereby also enables re-inhalation). All anoles therefore appear to be capable of forming a thin layer (or ‘plastron’) of air along their scales during submersion, but only semi-aquatics appear to make regular use of this ability (see plot below). Hydrophobic skin evolved in anoles long before it was co-opted for rebreathing in stream-dwelling species, and likely had nothing to do with the use of aquatic habitats. In this way, the innovation of underwater rebreathing apparently owes its origins to a fortuitous ‘evolutionary accident.’
Semi-aquatic anoles rebreathed more frequently than non-aquatics (from Boccia et al. 2021)
Although we observed regular rebreathing in all aquatic anole species we studied, we discovered some interesting differences in the way they go about it. There were three main locations along the head to which diving anoles would exhale bubbles (see image below). We noted some variation in the bubble positions used by semi-aquatics, perhaps indicating that are multiple ways to achieve the same rebreathing function.
Bubble positions and use percentages for five semi-aquatic anole species (Drawing credit: Claire Manglicmot)
To determine if ‘rebreathing’ was truly involved in respiration, we used our oxygen sensor to measure the oxygen concentration of the bubbles produced by diving semi-aquatics. This is not as easy as it sounds; bubbles were frequently re-inhaled quickly and diving anoles do not take kindly to being accidentally poked in the nose with a probe. But we persevered, and found that bubble oxygen levels decreased through time, consistent with the respiration hypothesis!
Experimental submersion of an A. maculigula male in Colombia; field assistant James is holding oxygen and temperature sensors ready.
We found some evidence that oxygen decrease followed an exponential decline curve, suggesting either that anoles extract some additional oxygen from the surrounding water by rebreathing (thus slowing the rate of oxygen loss from the bubble), or that metabolic rate (and thus oxygen demand) drops over time during submersion (see figure below). We compared our results to diving insects that use a similar rebreathing apparatus while submerged and found that anole oxygen use matches up well with our expectations for their sizes, and that the metabolic rate of anoles is probably too high for them to remain underwater indefinitely using oxygen captured from the water by the rebreathing bubble (the same is true for the largest diving insects).
Plots A-E show bubble oxygen concentrations through time for five species of semi-aquatic anole. Plot F shows a sham trial (in which I mimicked the bubble movements of diving anoles with a submerged syringe; no oxygen declines were observed). Plot G shows semi-aquatics (blue) and diving insect oxygen consumption rates (black) by mass. The dotted line indicates the theoretical limit of oxygen replenishment per second that could be supported by a bubble gill structure. From Boccia et al. 2021.
The consistency with which unrelated semi-aquatic anoles rebreathed suggests that rebreathing is adaptive for semi-aquatic living; however, our data currently do not allow us to favour a particular physiological functionality for this behaviour. Our top three (not mutually exclusive) hypotheses are: 1) rebreathing allows anoles to access air trapped in their head cavities or within the plastron, which might otherwise not be incorporated into their air supply; 2) the rebreathing bubble functions as a physical gill (as has been observed in diving insects), allowing diving semi-aquatics to extract some oxygen from the surrounding water; and 3) bubble exhalation and re-inhalation allows anoles to remove excess carbon dioxide which builds up during dives. We hope to investigate these possibilities during future work!
We published this work in Current Biology (Boccia et al., Repeated evolution of underwater rebreathing in diving Anolis lizards, Current Biology (2021), https://doi.org/10.1016/j.cub.2021.04.040)
Birt RA, Powell R, Greene BD. 2001. Natural History of Anolis barkeri: A Semiaquatic Lizard from Southern México. Journal of Herpetology. 35(1):161. doi:10.2307/1566043.
Brandon RA, Altig RG, Albert EH. 1966. Anolis barkeri in Chiapas, Mexico. Herpetologica. 22(2):156–157.
Campbell HW. 1973. Ecological observations on Anolis lionotus and Anolis poecilopus (Reptilia, Sauria) in Panama. Am Mus Novit. 2516:1–29.
González Bermúdez F, Rodríguez-Schettino L. 1982. Datos etoecologicos sobre Anolis vermiculatus (Sauria: Iguanidae). Poeyana. 245:1–18.
Henderson RW, Powell R. 2009. Natural history of West Indian reptiles and amphibians. Gainesville: University Press of Florida.
Herrmann NC. 2017. Substrate availability and selectivity contribute to microhabitat specialization In two Central American semiaquatic anoles. Breviora. 555(1):1–13. doi:10.3099/MCZ33.1.
Leal M, Knox AK, Losos JB. 2002. Lack of convergence in semi-aquatic Anolis lizards. Evolution. 56(4):785–791. doi:10.1111/j.0014-3820.2002.tb01389.x.
Muñoz MM, Crandell KE, Campbell-Staton SC, Fenstermacher K, Frank HK, Van Middlesworth P, Sasa M, Losos JB, Herrel A. 2015. Multiple paths to aquatic specialisation in four species of Central American Anolis lizards. Journal of Natural History. 49(27–28):1717–1730. doi:10.1080/00222933.2015.1005714.
Robinson DC. 1962. Notes on the Lizard Anolis barkeri Schmidt. Copeia. 3:640–642.
Hey there!
I’ve been wanting to do this anole for a while so I’m kind of excited. These posts keep me going sometimes when the news is rough. I hope anoles bring you some respite as well.
Anolis agassizi is an anole that is endemic to Malpelo Island (off the coast of Colombia).
The island has rocky terrain and no vegetation, and the anoles are not territorial, and will willingly overlap or share perches and food sources. The insects that they eat are mainly beetles that are attracted to the colonies of birds that nest there. They also seem to have an attraction to the colour orange.
Anolis agassizi males have an average SVL of 105.4 mm, and females at 85.2 mm. They are mainly predated on by the Malpelo (or Dotted) galliwasp and seabirds.
Large males have large nuchal crests that are permanently erect, unlike other anoles. The small morphs of the male anoles also differ in colour, having spotted heads like the females do. All males have very small dewlaps.
Some people think that the anoles with brown colouring and patterns are too drab or boring but honestly I appreciate their ability to blend in almost seamlessly to their habitats. The Blotchbelly Anole is another one of those, usually brown, sometimes with light patterning or a tan line down its back.
The males have a unique burnt sienna coloured dewlap, while the females of this species have no dewlap. Blotchbelly anoles appear to be twig anoles and they inhabit lowland forests in Ecuador and Colombia.
The anole gets its name due to the spotting (but not blotches) on its belly. Female Blotchbelly Anoles may be slightly larger than the males with a recorded length of 124-140 mm (Arteaga 2013), and the males at 120-129 mm.
Found from northwestern Ecuador to central Colombia, Anolis lyra is a trunk anole that gets its name (Lyre Anole) from the lyre shape on the back of its head.
As it is sympatric with several other Ecuadorean anoles, it helps that this one has distinct features, like the marking on its head and its very distinct dewlap that is red in males with a dark central spot, and grey-white in females (also with the spot). They have an SVL of about 77mm (males) and 73mm (females).
Anolis dracula can be found at ~2200m in the Andes in Ecuador and Southern Colombia, and is very similar in appearance to the Equatorial Anole. It can only be distinguished from Equatorial Anoles, that inhabit the same range, by closer examination of the skull or hemipene, or by genetic analysis. They have a snout-to-vent length of about 70-82mm. Female Dracula Anoles can also have a dewlap smaller than that of the male.
Dewlaps of A) Adult male Dracula Anole, B) Female, C) Subadult female, and D) Male Equatorial Anole. Images from Yánez-Muñoz et al. (2018)
They are also active on the ground, and were caught in pitfall traps as noted in Yánez-Muñoz et al. (2018), where the species is described.
Here’s a bit of lizard joy for you today! HUGE shoutout and credit to The Amphibians and Reptiles of Mindo by Arteaga et al. because I can’t find any natural history info about this anole anywhere but in this book. If you can get it, you should! Because of current events they can’t do their normal herping tours (Tropical Herping) and could use the support. Their photography is amazing and you can get calendars, posters and pocket field guides!
Anolis gracilipes, the Charm Anole, certainly is a charming little anole.
It’s been classified as a twig ecomorph, a group of small anoles whose bodies are adapted for narrow surfaces like, you guessed it, twigs. This little lizard can get up to 172-181 mm for males and 169-191 mm for females.
This anole has a brown colouring on its back, with triangular markings and green on its throat, down to its chest.
I found these two specimens in my farm located in the municipality of Santa Sofia, department of Boyacá, Colombia. The living specimen was found near a stream in a wet area, while the dead specimen was found in the house of the farm. The farm is located in an Andean forest at about 2300 meters above sea level where plants such as oaks and eucalyptus trees predominate, among others.
Observaciones realizadas en mi finca (Ibagué – Colombia) de un macho de Anolis huilae acechando su presa y una hembra predando su presa. He tenido la oportunidad de observar individuos de ésta especie cazando orugas, larvas y moscas y, la manera como ellos invierten algún tiempo para acechar a sus presas para capturarlas . Aún se desconoce la dieta exacta de esta especie de lagarto endémico de la cordillera Central de Colombia.
Predación por parte de una hembra de Anolis huilae
Editor’s note: Google translates the passage above as follows. It’s amazing how good this programs are getting!:
Observations made on my farm (Ibague - Colombia) of a male Anolis huilae stalking his prey and a female predating its prey. I have had the opportunity to observe individuals of this species hunting caterpillars, larvae and flies and how they spend some time to stalk their prey to catch them. The exact diet of this species of lizard endemic to Central Cordillera of Colombia is still unknown.
En el marco de mi tesis de maestría sobre la Ecofisiología térmica de Anolis huilae tuve la oportunidad de observar, creería que sería el primer registro, una pareja de ésta especie copulando en el tronco de un árbol. Evento que lo considero relevante por la falta de información acerca de ésta especie.
El estudio lo estoy desarrollando en el Corregimiento de Juntas, Ibagué (Colombia). Mi objetivo es conocer aspectos de la fisiología térmica de A. huilae y relacionarla con las temperaturas ambientales y microambietales de su hábitat. Para la colecta de datos me estoy apoyando con una cámara termográfica infrarroja (metodología no invasiva) y modelos de cobre con data loggers insertos en ellos.
Imagen termográfica de copula de Anolis huilae.
En una primera etapa del estudio estoy averiguando si A. huilae es una especie heliotérmica o tigmotérmica; como también, si es termoconformadora activa o termoconformadora pasiva. Datos que próximamente los compartiré.
Observaciones comportamentales, no registradas, ayudarán a conocer más aspectos de la biología y ecología de ésta especie, de la que aún falta mucho por descubrir. Así mismo, he observado en esta localidad la simpatría con otro anolis, Anolis antonii.
*****
English translation via the internet:
Record of Copulation of Anolis Huilae
In the framework of my master’s thesis on the thermal ecophysiology of Anolis huilae, I had the opportunity to observe, you would not believe that would be the first record, a couple of this species copulating in the trunk of a tree. Event that is considered relevant by the lack of information about this species.
The study, I am developing in the Corregimiento of seals, Ibagué (Colombia). My goal is to understand aspects of the thermal physiology of A. huilae and relate it to the ambient temperatures and microenvironments of its habitat. For the collection of data I am supporting with a infrared thermal imager (non-invasive methods) and copper models with data loggers inserts in them.
In the first stage of the study, I am enquiring whether A. huilae thermoregulation is a species or is thigmothermic; also, whether it is an active or passive thermoregulator. I will share the data soon.
Behavioral observations, unregistered, help you learn more aspects of the biology and ecology of this species, which still lack much to discover. Also, I’ve seen in this locality the sympatry with another anole, Anolis antonii.
