Blue spiny lizard owns a small stronghold in Texas
The blue spiny lizard (Sceloporus cyanogenys) is one variety of 10 species of spiny lizards that reside here in Texas, although it has a very limited range in this state. It can be observed in Texas roughly from just south of Eagle Pass along the Rio Grande to Brownsville, only occurring in spotty distribution any distance away from the border. However, through the use of the citizen-science app known as I-naturalist, there now seems to be a healthy population just to the northwest of Austin; whether this is a naturally occurring population or the result of animals being transported and released has yet to be determined. Outside of the US this species occurs in the Mexican states of Coahuila, Nuevo Leon and Tamaulipas.
Members of this genus are often called “tree-lizards” or “fence-lizards” by those who are observant enough to witness them, but this form is found almost exclusively in rocky areas, specifically areas that have boulders that provide shelter for this lizard. Other habitats include man-made structures such as abandoned buildings, concrete signs and even bridges.
The blue spiny lizard is the largest member of its genus in this state, with adult males frequently achieving lengths over 11 inches. The record size is actually just over 14 inches. It is quite spinose; its scales along the dorsal area being very large and spiny. The background coloration of this reptile varies depending on a variety of factors such as age, season, time of day and temperature. Generally, the background coloration is grayish brown with numerous obscure, yet visible crossbands. During the heat of the day, this lizard will oftentimes have a blueish metallic sheen which is where the common name is derived from. There is a large, distinctive black collar that is outlined on both sides by a light ring on the neck.
The belly is usually cream-colored, and males have two dark blue patches on either side of their belly, as well as on the throat. The tail is somewhat long, and when un-regenerated it is adorned with dark and light crossbands with a brilliant sheen of turquoise. Just like other members of its genus, its tail can be utilized as a defensive strategy. If the tail is grabbed by a predator it is easily severed from the lizard. This defensive move is known as autotomization. This is where the tail comes off rather easily, and while the potential predator is pre-occupied with the still moving tail, the lizard can crawl away to safety. Over time, the lizard will regenerate a new tail, although this new one is never as long or as colorfully banded as the original.
Blue spiny lizards, like other lizard species, are “cold-blooded”, or technically, ectothermic. This means that they do not generate heat from the inside of their body, as mammals and birds do, but rather are dependent on outside sources for heating and cooling. They are primarily active during the summer months but can be seen occasionally during the winter months on warm days when temperatures achieve a level that allows activity.
This species of spiny lizard is strictly carnivorous, and its primary food items include grasshoppers, wasps and beetles. Smaller lizards will occasionally be consumed as well.
They are also unique to most other spiny lizards in the fact that rather than laying eggs, this type instead produces live young. After mating in the fall, the female will give birth to a dozen or so live babies the following summer. These delicate three-inch long versions of the parents arrive in the world looking like duller versions of the adults.
Blue spiny lizards are quite numerous within the boundaries of their selected habitat and range. In many instances, I have witnessed a dozen or more basking on the large concrete entrance signs to several of the state parks that are in the Lower Rio Grande Valley.
Michael Price is owner of Wild About Texas, an educational company that specializes in venomous animal safety training, environmental consultations and ecotourism. Contact him at wildabouttexas@gmail.com.