Category: Natural History Observations Page 4 of 34

An adult nipping grass in the morning; notice the bluish tinge on the inner side of the thigh and dorsal part of tail.

Here is Saara hardwickii , spiny tailed lizards. I observed these lizards in their natural habitat, in the Thar desert in Indian state of Rajasthan. It’s a medium-sized lizard which dwells in semi-arid to arid landscapes of northern India, Pakistan and some regions beyond. A drab colored lizard with a pug head and a distinct fleshy and spiny tail.

Habitat fragmentation and hunting for its tail is the main reason for its dwindling numbers. Folklore has it that its tail has aphrodisiac powers, so its tail is cut and ‘oil’ extracted from it and consumed for the intended purpose.

Interestingly, like iguanas, these lizards also live in a social structure, a ‘society’ composed of adults as well as young ones. They live in ground burrows or termite mounds. Spiny-tailed lizards are diurnal; their activity starts around early morning sun and when the sun sets, surprisingly not even a single individual can be seen! A considerable ontogenic shift in dietary inclination towards herbivory can be seen. Adults feed on grass or diminutive terrestrial flora, whereas young ones are omnivorous, feeding on arthropods.

This fellow was just out of its home and carefully observing its habitat.

There are several previous posts concerned with lizards missing feet or limbs (1, 2, 3). At the risk of being monotonous, here is another. I caught this male green anole (Anolis carolinensis) in Auburn, AL this morning (6.24.16). He was sitting on someone’s porch railing at my apartment complex. In addition to his front left limb he was missing 2 fingers on the front right hand and one on the back left foot. He has no other signs of damage, however, not even any evidence of a regenerated tail. I think what sets this example apart from ones previously given is that the entire limb is missing. There is only a tiny nub of bone at the shoulder, and a small flap of skin. Interestingly, the tiny nub moves back and forth beneath the skin when he runs, as if the entire limb were still present and useful.

We (Warner Lab) have had lizards hatch without limbs in the past. We even had one (A. cristatellus) hatch this year with 6 limbs (three front right arms). It is possible that this carolinensis never developed this limb to begin with; however, the tiny flailing nub and flap of skin make me feel that is not the case. Anyhow, this guy seems fat and happy and still moves pretty fast, despite the handicap.

Juvenile Anolis aquaticus wakes up for science, Photo: Jonathan Flanders

One of the many wonderful things about anoles is that anole-hunting can be a 24/7 experience, as many nocturnal Anole Annals adventurers have shown and I’ve noted before. As an undergraduate, I spent many days and nights scanning trunks, leaves, sticks, bushes, etc. for anoles — a habit that got so ingrained that I still do it while hiking around northern California. So, logically, when I found myself in Costa Rica for the last field season of my Ph.D. (which is on bats), I had to do some lizard spotting, if only to remind myself of the good old days when I studied animals that don’t fly or bite. (Ok, anoles bite but that’s what makes them such great fashion accessories.) As I was already up until all hours of the night, I decided to check out where anoles were sleeping. There happened to be a small group of aquatic anoles living near my cabin and I (along with my batty colleague) noticed that each night they seemed to be in the same place — one email to Jonathan later and we wrote up a short note for Herpetological Review about sleep site fidelity in Anolis aquaticus.

Who turned the sun on? Photo: Jonathan Flanders

We observed the lizards for 16 nights over a period of 24 nights and found that of the six individuals, they were in the same place almost 80% of the nights, which is very high compared to what has been found in some other species. All of the lizards were perched in such a way that they were either obscured from view or had easy access to water to escape from predators. The area was particularly dry at that time so this may have reduced the number of suitable sleep sites for these aquatic lizards or maybe aquatic anoles are just pretty faithful to their sleep sites. In any case, it was a lot of fun to go back to my lizard-y roots and find some sleepy anoles.

At the other end of the world in the Indo-Malayan realm (in India, down south in the sky islands of Western Ghats), a Calotes rouxii male is advertising itself. He is displaying his bright red head on its black body. Even the dewlap region is almost black. Facial region is almost completely bright red along with nuchal and spinal crest.  Male display of this lizard is like many Anolis sp. A male typically does some pushups , ducks and bobbles his head to display his dominance in physical prowess and colour.

Calotes rouxii male.

Female or juvenile male of Calotes rouxii.

Calotes rouxii male

“This is not a Spring Break trip to Costa Rica, it is a herpetology class trip to Costa Rica that happens to be over Spring Break.” So said Jonathan Losos to a room full of eager students, many of whom had chosen to take Herpetology in part because of the adventure that awaited them. As first year Ph.D. students in the Losos lab, we were as excited as anyone for the opportunity to see some of Costa Rica’s rich biological diversity. Plus the well-publicized stereotype of how young people spend Spring Break has never really appealed to us. We’d rather be in the nighttime forest with a headlamp.

The lichen anole, A. pentaprion

The trip started with a day and a half at Veragua Rainforest. We saw tons of frogs and a handful of snakes, but anoles were hard to come by except for a few individuals along shallow, slow-moving streams (A. humilis, A. limifrons, and A. oxylophus). One of our most exciting finds of the trip was along one of these streams – an A. pentaprion hugging a narrow stem at eye level. It was shocking to see this lizard so close to the ground as it is often found high in the canopy and has even been observed gliding between perches. While many mainland anoles don’t fall clearly into the classic ecomorph categories, this lizard, with its small legs, long body and head, and slow but sneaky evasive behavior, is very reminiscent of West Indian twig anoles (and he’s got a gorgeous dewlap too! see photo at end of post).

From Veragua we moved to La Selva Biological Station where we spent five action-packed days exploring the forest and documenting the herpetofauna.

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