Archives of The Cold Blooded News

The Newsletter of the Colorado Herpetological Society

Volume 31, Number 7;   July, 2004

New Mexico Whiptail (Cnemidophorus neomexicanus)

State Reptile of New Mexico

C. neomexicanus was designated the state reptile earlier this year along with the New Mexico spadefoot toad (Spea multiplicata (Cope, 1863)) as the state amphibian. These species were selected by public voting at various events where the New Mexico Herpetological Society presented pictures and descriptions of several herp candidates to represent the state. Some folks wanted a rattlesnake to show how tough the state is or a homed lizard because they are cute, but in the end the New Mexico whiptail garnered the votes to represent the state. This is more fitting than it seems as this is a durable little lizard, well adapted to the often harsh conditions of this state and, like the many immigrants to the state, the New Mexico whiptail has a proven mastery of adapting to new environments and disturbed habitats.

The New Mexico whiptail is one of some 130 species in the family Teiidae. This is a New World family with 39 genera that occur in the Americas and the West Indies. Whiptails are in the genus Cnemidophorus and there are 13 species found in New Mexico. The New Mexico whiptail is particularly common along the Rio Grande drainage from Espanola in the north to Texas in the south, and in the west around the Gila River drainage area to the Arizona border and eastward to the Tularosa Basin. There is an isolated population around Conchas Lake in eastern New Mexico and another in the Petrified Forest National Park in Arizona; both introduced by man. Throughout its range, the New Mexico whiptail may cohabitate with several whiptail and other lizard species. While it may not outnumber other lizard species in any given area, it is often encountered by man as it forages for insects during daylight hours. It is an effective predator of various insects and can be seen moving with a jerky motion as it turns over leaves and investigates other hiding places for caterpillars, beetles, and even ants.

The New Mexico whiptail is far from the largest of our native lizards with snout to vent (SV) lengths of only 70 to 80 mm (2¾ to 3¼+ inches) and a total length of maybe twice that. It has a gray brown background color with six or seven light yellow longitudinal stripes. The middle dorsal stripe and occasionally the two on either side are wavy or zigzag (a key field identification feature). There is small light yellow spotting between the lowest stripes on the side of the animal. The tail is a pale greenish brown and the underside is often pale blue. The dorsal scales are minute (71 to 80 across the dorsum) and present a granular skin texture while the ventral scales are large shiny rectangular scales in eight lengthwise rows. The young sport an identical pattern with a more intensive coloration of a slate or black background with yellow to white stripes and a bright blue tail..Of particular note is that all New Mexico whiptail lizards are female. They reproduce through a process called parthenogenesis (from the Greek parthenos, virgin, and genesis, birth), where the eggs of the female divide and form viable young (all female, of course) without male fertilization. This is the case in 8 of the 13 New Mexico species and is also known to occur in various Pacific island geckos. Studies indicate all New Mexico whiptails in the Rio Grande drainage may be from "a single parthenogenetic lineage" or all descended from a single female lizard (Degenhardt, et al., 1996). It further seems this single female was the result of the cross breeding or hybridization between the little striped whiptail (Cnemidophorus inornatus) as the paternal line and the western whiptail (Cnemidophorus tigris marmaratus) as the maternal line. Both of these species have much broader ranges than the New Mexico whiptail (including the Rio Grande drainage) and both are populations of male and female.

The New Mexico whiptail lays eggs during June and July and there are two eggs per clutch. The eggs take approximately two months to hatch and one third of the females may lay a second clutch. The young hatch out with the vivid coloring described earlier and fully able to chase down and eat a variety of insects. Hibernation occurs in the fall and lasts until about April.

Captive care requires broad-spectrum lighting and a heat range from 75°F to 90°F. A basking spot will aid the lizards in achieving proper temperature. The cage should be fairly large with several hiding spots as these are active lizards. Water can be provided with occasional misting or a shallow water dish, as most specimens seem to quickly adapt to the use of standing water. Food should be varied with gut-loaded crickets serving as the mainstay. Calcium and vitamins can be provided as an occasional dusting on the feeder crickets. Care must be taken in handling whiptails as this family can and will readily release their tail. The re-grown tail will be shorter and less colorful.

References:
Degenhardt, William G., Painter, Charles, W., and Price, Andrew H. 1996. Amphibians and Reptiles of New Mexico, University of New Mexico Press, Albuquerque, N.M., pp. 431.
Stebbins, Robert C. 2003. Western Reptiles and Amphibians, 3rd edition, Peterson Field Guide Series, Houghton Miffiin Co., Boston, MA., pp. 533.