Blunt-nosed leopard lizard (Gambelia sila)

KingdomAnimalia
PhylumChordata
ClassReptilia
OrderSquamata
FamilyCrotaphytidae
GenusGambelia (1)
SizeMale total length: up to 35.7 cm (2)
Female total length: up to 33.4 cm (2)
Male weight: up to 60 g (2)
Female weight: up to 47g (2)

The blunt-nosed leopard lizard Classified as Endangered (EN) on the IUCN Red List (1).

The endangered blunt-nosed leopard lizard (Gambelia sila) is a relatively large lizard with a long, rounded body and well developed limbs (3). It is similar in appearance to the long-nosed leopard lizard (Gambelia wislizenii), but has a shorter, snubbed snout and a more triangular head shape (4).

The colour of the blunt-nosed leopard lizard may vary with the surroundings, but it is generally light-grey to yellow, with pale cream coloured-rings around its body and small dark brown spots in between these (4) (5). This species is unusual in that the male and female do not display permanent colour differences, but rather develop these during the breeding season (6). The male develops a salmon pink colour over the head and body, while the female develops rusty-red markings along the sides of the head and body (6).

The male is also distinguished by being larger than the female and possesses a broader head (2) (4).

The blunt-nosed leopard lizard is endemic to California in the United States, where it occurs only in the San Joaquin Valley and nearby area (1). It is found at elevations ranging from 30 to 730 metres (3).

This species usually inhabits semi-arid areas including grasslands and alkali flats (1) (4). The blunt-nosed leopard lizard also prefers sparse vegetation and areas with an abundance of rodent burrows in which to shelter. The soil in the habitat can be sandy, gravelly or loamy (a fertile soil mix of sand and clay) (1) (4). 

The blunt-nosed leopard lizard is unable to survive on lands that have undergone cultivation, and repopulation of these affected areas is thought to take at least 10 years (1).

The elusive blunt-nosed leopard lizard is diurnal, emerging from the refuge of a small mammal burrow in the morning to bask in the sun (5) (7). Each lizard will use several burrows, and will even construct a simple, shallow burrow of its own where mammals are scarce (5) (7).

The blunt-nosed leopard lizard is an agile predator, being able to leap up to 60 centimetres in order to catch prey in mid-air (7). It is generally opportunistic, stalking and feeding on prey that is both abundant and easily-caught. Its diet typically consists of insects such as grasshoppers, beetles, bees, wasps and ants (7) (8). It is also known to feed on lizards, including young of its own species, as well as plant matter (8).

The adult blunt-nosed leopard lizard emerges from a period of dormancy, known as brumation, in early April. Reproductive activity begins within the month and can continue up until the end of June (5) (7). The male will defend a territory and mate with any receptive females within it. The female will lay a clutch of eggs in a chamber of a burrow, and can produce between one and six eggs at any one time (2). The number of eggs produced is thought to be related to body size (7). The female usually lays one clutch per year, but this can increase when environmental conditions are favourable (2).

The young blunt-nosed leopard lizards hatch after about two months, from early July until late August, and remain active until October or early November (2) (7). They then enter a period of dormancy in an underground burrow until the following spring (5). The blunt-nosed leopard lizard has been known to live for up to almost five years, but a lifespan of around two years is more normal (2).

The major threat to this species is the disturbance and destruction of its habitat for purposes such as cultivation and urbanisation (1) (5). Construction of facilities and dumping of waste related to gas and natural oil extraction has led directly to blunt-nosed leopard lizard mortalities (5).

The use of pesticides on agricultural land may also impact on populations both directly and indirectly, through the removal of this species insect prey (5). The use of off-road vehicles is also thought to have a detrimental effect on the habitat of the blunt-nosed leopard lizard, an it is also known to have been directly killed by vehicles on roads (1) (2) (5).

The blunt-nosed leopard lizard is protected by law in the United States and is currently covered by the conservation efforts of the Endangered Species Recovery Program, which aims to research and produce recoverey programmes for endangered species in the San Joaquin Valley (9). Efforts so far have included large-scale habitat and population surveys in order to better understand this elusive species (5). Future recommendations include determining appropriate habitat management and protecting additional habitat (5).

The blunt-nosed leopard lizard is also known to occur in some protected areas, such as the Pixley Wildlife Refuge (4).

Find out more about the blunt-nosed leopard lizard and its conservation:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (August, 2011)
    http://www.iucnredlist.org/
  2. Germano, D.J. and Williams, D.F. (2005) Population ecology of blunt-nosed leopard lizards in high elevation foothill habitat. Journal of Herpetology, 39(1): 1-18.
  3. CaliforniaHerps - Gambelia sila (August, 2011)
    http://www.californiaherps.com/lizards/pages/g.sila.html
  4. Stebbins, R.C. (2003) A Field Guide to Western Reptiles and Amphibians. Houghton Mifflin Company, New York.
  5. U.S Fish and Wildlife Service (1998) Recovery Plan for Upland Species of the San Joaquin Valley, California. Portland, USA. Available at:
    http://esrp.csustan.edu/publications/pubhtml.php?doc=sjvrp&file=chapter02K00.html
  6. Germano, D.J. and Williams, D.F. (2007) Ontogenetic and seasonal changes in coloration of the blunt-nosed leopard lizard (Gambelia sila). The Southwestern Naturalist, 52(1): 46-53.
  7. Montanucci, R.R. (1965) Observations on the San Joaquin leopard lizard, Crotaphytus wislizenii silus Stejneger. Herpetologica, 21: 270-283.
  8. Germano, D.J., Smith, P.T. and Tabor, S.P. (2007) Food habits of the blunt-nosed leopard lizard (Gambelia sila). The Southwestern Naturalist, 52(2): 318-323.
  9. California State University: San Joaquin Valley Endangered Species Recovery Program (August, 2011)
    http://esrp.csustan.edu/