Category: Natural History Observations Page 14 of 34

Adult male Anolis onca from Isla de Margarita basking.

Continuing the recent interesting post on the Beach Anole Anolis onca, I decided to write something about my personal experiences with this amazing species and attempt to summarize some of what already exists in the literature. Famous by its lack of expanded, smooth, infradigital lamellae, there is a lot more to these beautiful lizard.

Typical habitat of Anolis onca on Isla de Margarita

This “beach” anole is basically endemic to Venezuela (it is also found on a narrow portion of adjacent Colombia). Within Venezuela, Anolis onca has a disjunct distribution (more on that below). It ranges continuously along the coast of the states of Zulia and Falcon in the West. It is also found on the islands of La Tortuga and Margarita, as well as along the coast of the state of Sucre in the East. Another, possibly disjunct population has surprisingly been recorded from dry savannas well inland in the state of Monagas! I have observed A. onca in western Venezuela, but I am most familiar with populations from Isla de Margarita. I have traveled countless times to the island and since I was a kid I always remember being fascinated by these fairly large, active anoles. On Isla de Margarita, A. onca is definitely ubiquitous. It is easily found on thorn scrubland, coastal sand-dune environments, and beaches. It is also common around human habitation. I have always observed this anole in sites with constant and strong wind currents. Several authors have suggested that the windy conditions present in the habitats preferred by this lizard may have prevented it from being strictly arboreal like other anoles (Williams, 1974; Miyata, 1975; Kiester, 1977).

These guys have a really large, beautiful dewlap

Whatever the case, it is definitely more terrestrial than other anoles (even species that are commonly found on the ground, e.g. Anolis planiceps) and I have observed it numerous occasions on open ground. However, it often climbs up to about 1.5 m on shrubs, cacti, vines or rocks. Around human habitation it also perches on unfinished walls of buildings, cobble and fence posts (same places frequented by the larger Tropidurus hispidus on the island). I also have observed A. onca on open sand banks of beaches in close proximity to salt water (Ugueto and Rivas, 2010). Williams (1974) also mentioned finding this species near the seashore. Interestingly, light colored specimens are very well camouflaged amidst the sandy soil. I have noticed that when A. onca perches on low shrubbery it often just exposes its head above the leaves. I do not recall seeing such behavior in other anole species.

Most individuals remain motionless when first spotted. If you get too close for comfort, lizards invariably run towards and hide within nearby bushes, clumps of herbaceous vegetation or thorny shrubs. Occasionally they may hide beneath rocks or boulders. Collins (1971) reported that some specimens escape into Ocypode crab holes after lizards were pursued for long time, but I have never observed this behavior. Various types of small arthropods like grasshoppers, robber flies, beetles and spiders have been reported as prey (Roze, 1964; Kiester, 1977; Ugueto and Rivas, 2010). Kiester (1977) reported that the analysis of 38 stomachs revealed that a particular species of chrysomelid beetle constituted a large portion of the diet in western Venezuelan lizards. Saurophagy has also been reported in this species; Miyata (1975) and Kiester (1977) recorded a large individual preying on a female Cnemidophorus lizard in northwestern Venezuela. I observed this species preying on small flies that passed near the lizard on a beach on Isla de Margarita. Kiester (1977), however described a very interesting mode of predation in which the lizard stalked fast moving robber flies in a cat-like fashion using the irregularities of the terrain as cover and dashing towards prey when at close range. What is known about the reproduction of this species is fragmentary at best, but it appears it could be seasonal on northwestern Venezuela. Kiester (1977) reported females laid eggs after the rainy season so that hatchlings come out during January, February and probably March.

Distribution of Anolis onca and the closely allied Anolis annectens in Venezuela. Notice the disjunct distribution of onca.

As I mentioned earlier, the distribution of A. onca in Venezuela is disjunct and the western and eastern population are separated by a long stretch of apparently suitable habitat.

World Turned Upside Down

By Jonathan Losos

On April 23, 2013

In Introduced Anoles, Natural History Observations

Your intrepid correspond is currently in West Palm Beach, Florida, about to embark on a meandering trip north in quest of yellow-dewlapped brown anoles and other anole curiosities (speaking of which, anyone know a good site to find A. sagrei with a lot of yellow in their dewlaps? Like half or more?). In any case, today’s curiosity occurred as I was walking through a large condo development. Out of the corner of my eye, I saw something double surprising. The first surprise was that it was a knight anole–I wasn’t aware that they had spread so far from Miami, although a subsequent google search revealed that, in fact, they are not only known from West Palm, but also from considerably further to the north (see map above).

The second surprise was where the lizard was. It was on the ground. Well, from the corner of my eye, it seemed like it had hopped from the ground, but when I actually turned to look, it was on a tree trunk, about 10 cm off the ground. Still, quite low, not where you expect to find a crown-giant. Sean Giery coincidentally wrote a post about female knight anoles laying their eggs in holes on the ground, so that’s a possible explanation, though this was a little knight, more of a knightlet, at ca. 130 mm svl.

Excited by the spotting of such a noble beast, I forsook the brown anoles and began looking for the big greens. And they were remarkably abundant! In about an hour of meandering, I found 13! Some were high up in the tree, right where they should be (you can see the silhouette of one in the photo to the left), but others were much lower (photo on right), and one was on a shuffleboard court (below)! In addition, as I posted recently, evidence of terrestrial habitat use was also found post-mortem by the discovery of a two-dimensional equestris on the one-lane road running through the complex.

Site of the terrestrial knight anole spotting. A careful look will reveal that Anolis equestris isn’t the only terrestrial lizard in this habitat.

Why is it that these lizards are on the ground? Well, for one thing, this is not a forest, but a condo subdivsion. There are plenty of trees, but most have been planted and they are spaced out. Many of the knight anoles I found were in trees there were completely isolated, such as the one in the photo on the left. In other words, to get from one tree to another, or to colonize a tree in the first place, the big lizards have to move on the ground. There’s been very little work on knight anole ecology and habitat use–it would be really interesting to see how often they move from one isolated tree to another.

But these low-riding knights (in the Jansonian sense) are only half of the reason that I’ve titled this post “World Turned Upside Down.”

Anoles Feeding On Liquids – Please Help

By Gerrut Norval

On April 22, 2013

In Ask the Experts, Natural History Observations

Anole feeding on nectar. What about sap? Photo by Sparky Leigh.

Good day everyone. I am currently working on a short manuscript about a brown anole that I observed feeding on sap. I am aware that some anoles will feed on nectar (see list below), but I would like to know if anyone has ever observed anoles feeding on sap? If you have any references pertaining to anoles feeding on nectar or sap, and it is not listed below, would you please e-mail it to me at a_sagrei@hotmail.com, or at least provide me with the reference so that I can try to obtain it myself. Thank you very much.

Gerrut

P.S. Lizards rule!

References I am aware of:

Campbell, T. and C. Bleazy. 2000. Natural history notes: Anolis carolinensis (green anole). Nectivory and flower pollination. Herpetological Review 31: 239.

Colón Archilla A.D. 2010. Nectivory in Puerto Rican emerald anoles (Anolis evermanni). IRCF Reptiles and Amphibians 17: 144–145

Echternacht, A.C. and G.P. Gerber. 2000. Anolis conspersus (Grand Cayman Blue throated Anole). Nectivory. Herpetological Review 31:173.

Liner, E.A. 1996. Natural history notes: Anolis carolinensis carolinensis (green anole). Nectar feeding. Herpetological Review 27: 78.

Okochi, I., M. Yoshimura, T. Abe, and H. Suzuki. 2006. High population densities of an exotic lizard, Anolis carolinensis and its possible role as a pollinator in the Ogasawara Islands. Bulletin of the Forestry and Forest Products Research Institute 5: 265–269.

Perry, G. and J. Lazell. 1997. Anolis stratulus (Saddled Anole). Nectivory. Herpetological Review 28:150–151.

Perry, G. and J. Lazell. 2006. Anolis pulchellus (Grass Anole). Nectivory. Herpetological Review 37:218–219.

Rios-Lopez, N. 2004. Anolis stratulus (Saddled Anole). Extrafloral herbivory. Herpetological Review 35:386.

Timmermann, A., B. Dalsgaard, J.M. Olesen, L.H. Andersen, and A.M. Martin Gonzalez. 2008. Anolis aeneus (Grenadian Bush Anole). Anolis richardii (Grenadian Tree Anole). Nectivory/pollination. Herpetological Review 39:84–85.

Valido, A.M. 2006. Anolis allisoni (Allison’s Anole/Cameleon Azul). Nectar feeding. Herpetological Review 37:461.

Nesting Knight Anoles

By Sean Giery

On April 21, 2013

In Natural History Observations

Female Knight anole digging nest at the base of an oak. April 2013

On my way to teach biology lab the other day, I ran into this female knight anole (actually, my buddy Zack is the one who spotted it). She was obviously spooked by us and after snapping a few photos I backed off to see if she would continue nesting. After a few seconds she returned to her task. I don’t know why I imagined anoles would dig with their hind legs, but for some reason I did. However, she continued to excavate with alternating strokes of her front feet. Unfortunately I had to run to a meeting, but when I returned a few hours later her hole was still there. Zack had stayed behind to watch her progress and reported that she had aborted the endeavor when a bicyclist whizzed past a bit too close. The hole was about 4 centimeters deep and 5 wide into the mineral soil when she left.

Female Knight anole observed digging nest at the base of a large fig tree. Note the soil under her front claws and on her snout. Observed July 2012.

This is the second time I’ve seen nesting knight anoles in Miami. The first was last summer when I found a very healthy looking female at the base of a fig tree. There was dirt on her snout and a small hole where she had been. In both cases, the nesting females were within 1 meter of a tree, and both were excavating with their front feet and possibly their snout. Also, the dates of each observation show that there is a protracted nesting season in South Florida that includes April 10^th to July 20^th. Such a long season explains the variable size of first year knight anoles that I find during the spring.

Anolis Equestris Dead On Road

By Jonathan Losos

On April 20, 2013

In Natural History Observations

Here’s something you don’t see every day. More on these guys soon.

Anolis Annectens, The Retrograde Anole

By Jonathan Losos

On April 20, 2013

In Natural History Observations

: Anolis annectens. Photo by J. Losos.

No flies on you guys–this remarkably obscure anole was quickly identified. So, what’s its claim to fame?

Well, we have to backtrack to Anolis onca for a minute. Faithful AA readers will recall that A. onca is the only anole lacking a subdigital toepad. For this reason, at one point it was placed in its own genus, Tropidodactylus. However, in 1974 Ernest Williams described a new species in Breviora based on a single specimen found in a jar of A. onca in the Field Museum in Chicago. At that time, Anolis was characterized by having expanded scales under phalanxes ii and iii of the toe, whereas Tropidodactylus, of course, had none (phalanxes are the bones in a toe–humans have three per finger, for example). What was remarkable was that the new specimen had expanded scales under phalanx ii, the Anolis condition, but only keeled scales under phalanx iii–it was intermediate between the two, hence the specific name annectens. Here’s an image from Williams’ paper and a photograph of an annectens toe.

From Williams (1974).

Anolis annectens foot. Photo by J. Losos.

Anolis annectens foot. Note the lamellae under only one toe bone. Photo by J. Losos.

The term “retrograde” comes from Williams’ paper and refers to the idea that A. annectens and A. onca illustrate a morphocline in toepad reduction–halfway gone, then all the way gone. Incidentally, recent molecular studies confirm that the two species are sister taxa.

Amazingly enough, A. annectens occurs in the same general region as A. onca, near Lake Maracaibo in Venezuela. In 2007, Tito Barros and colleagues reported in Tropical Zoology on the collection of an additional 22 specimens of A. annectens, confirming that the one individual wasn’t a freak. They also provided information on coloration, geographic distribution (it still hasn’t been found in sympatry with A. onca) and some data on ecology.

Since we were in the area any way, we decided to go and look for them after collecting data on A. onca. By “we,” I mean Tito Barros, Gilson Rivas, several students of theirs, and Rosario Castañeda. Anthony Herrel was busy back at the field lab conducting performance trials (sprint speed, bite force), and I was on assignment finding discarded cardboard boxes to make a proper racetrack.

The weather was beastly hot, about 110 degrees Fahrenheit, with no wind. Here’s what Rosario had to say:

Burrowing Owl Predation On Brown Anoles

By Jonathan Losos

On April 15, 2013

In Natural History Observations

Rob Heathcote posted this photo as a comment on Sean Giery’s post on bird predation on anoles, but the photo is so spectacular that we need to make sure everyone sees it.

Red In Beak And Talon: A Few Observations Of Birds Consuming Anoles In Urban South Florida

By Sean Giery

On April 15, 2013

In Introduced Anoles, Natural History Observations

A few years ago I asked an ornithologist friend of mine what urban birds such as starlings and house sparrows ate. His answer was that it was probably a mix of bottle caps, cigarette butts, and McDonald’s French fries. I’m only partially satisfied with that answer, and so try to keep an eye on what urban birds eat wherever I go.

Since moving to Miami four years ago, I’ve observed several cases of birds consuming anoles. After watching a Common Grackle feed an anole to a fledgling a few days ago, I thought I’d compile and share these observations with AA readers.

Twin embryos

By JessicaStapley

On April 13, 2013

In Natural History Observations

Twin embryos of A. apletophallus dissected from a single egg that failed to hatch.

During my research project on A. apletophallus I dissected many eggs that failed to hatch but I was very surprised to discover two embryos in this egg. The female had mated in the wild and laid many normal single embryo eggs before and after this one. Twin embryos have been observed in other lizards (e.g Agama agama (Herptelogica 1967,23:57), leopard geckos and bearded dragons) but I did not find any previous report in anoles. Thought it my interest the AA readers. Anyone else seen this?

Anolis Tigrinus, Another Mainland Twig Anole

By Jonathan Losos

On April 11, 2013

In Natural History Observations

Anolis tigrinus. Photo by Anthony Herrel

The last leg of our Little Known Mainland Anole Tour took us to the mountains above Caracas, in quest of Anolis tigrinus. A “mystery anole” photo of that species was put up on AA in December, and savvy readers quickly pegged it as a mainland species, noting it’s twig anole-like appearance. Moreover, the only publication on the natural history of this species, by Ugueto, Rivas, Barros, and Smith, suggested it was a twig anole as well. Given our previous work that had identified the twig anolishness of A. proboscis in Ecuador and A. (Phenacosaurus) heterodermus in Colombia (earlier in this trip), we’re beginning to see a trend: twig anoles seem to be the one kind of West Indian ecomorph that has evolved many times on the mainland (the A. pentaprion clade is another candidate).

Colonia Tovar

So, fresh from the beaches of Maracaibo, we headed to the mountains in quest of the tiger anole. A last minute change in plan led us to the little town of Colonia Tovar at about 7000 feet in elevation. We didn’t know what to expect from TC, but Wikipedia describes it as “Germany in the Caribbean.” Established by settlers from Baden (now part of Germany) in the 1850’s, the town gradually declined for a century, before reinventing itself as a kitschy tourist trap in the 1960s, and now it’s booming. And it was delightful. All of the buildings seemed straight out of Bavaria, there were brewhauses and wienerschnitzel (see photo at bottom of post), the waitresses wearing their fraulein get-ups.

The friendly locals in Colonia Tovar

We stayed at a delightful little hotel, Cabañas Heidelberg. And for no extra charge, we were able to go lizard hunting in the little patch of woods out back.