San Diego Management & Monitoring Program


Orange-throated whiptail
Aspidoscelis hyperythra

Vertebrata
Autarchoglossa

Vertebrata Autarchoglossa
Kingdom Phylum Subphylum Class Order Suborder Family

Current distribution rangewide

Ranges from the southern edges of Orange and San Bernardino Counties, the Corona-Riverside-Colton areas of Riverside County southward through the Elsinore and Perris Basins, and through coastal and low-elevational areas of San Diego County [1]. Can be found on the coastal slope of the Peninsular Ranges-and extends from near sea level to 1040 m (northeast of Aguanga, Riverside County) [2].


Known Populations in San Diego County

Within the MSPA, occurrences have been found in MU 3 (MarronValley Mitigation Bank), MU 4 (Hanson Pond-El Monte Valley), MU 5 (Boden Canyon), and MU 6 (Rancho La Costa HCA).


List status

None.


Habitat affinities

Occurs primarily on coarse soils in open coastal sage scrub vegetation [3, cited in 1]. Also inhabits chamise-redshank chaparral, mixed chaparral, and valley-foothill hardwood habitats [4]. Associated with the presence of some perennial plants such as buckwheat (Erigonum fasciculatum), low, open chamise (Adenostoma fasciculatum), and white sage and black sage (Salvia apiana and S. mellifera) [1] due to its food source, termites [5], and its necessary requirement of a perennial plant as a food base [6, cited in 2]. Occurs along the edge of open, dry, riparian areas, along trails, along dirt roads, and in areas of light off-road vehicle use [1].


Taxonomy and genetics

This taxon is morphologically distinct [7] and has never been confused with any other taxon [2].


Seasonal activity

Emerge from hibernation in February or March [6, cited in 2] through April [8]. May be active in every month of the year whenever it is sufficiently warm [1;6, cited in 2;8]. Adults especially active in the spring and less active in the fall [1]. Diurnal [8]. Daily activity occurs within a narrow range of substrate temperatures (36.3°C-41.0°C), clearly avoiding high midday temperatures [6, cited in 2;8;9]. Adults enter into hibernation late July to late September [9], with immature lizards entering hibernation late December [6, cited in 2;8].


Life history/ reproduction

Breeding season lasts from May through mid-July [10;11]. Sexually maturity reached in 1 year, but most individuals, especially females, require 2 years to become sexually mature [12]. Females deposit two or three moderate-sized, leathery-shelled eggs in June or July in an unknown location. Mean clutch is small (2.3 eggs). Incubation lasts from 50 to 55 days [10]. Hatchlings emerge from August through October [1]. Longevity is unknown [2].


Diet and foraging

Feeds primarily on termites [5]. Will feed on other insects such as spiders, beetles, and grasshoppers during the late summer [6, cited in 2]. Forages actively on the surface and scratches through surface debris [4]. Regularly stops movement momentarily to probe for food within leaf litter, shallow burrows, and loose soil [9].


Dispersal

No migration [4]. Home range of 6 males averaged 0.07 acres, while that of 5 females averaged 0.15 acres. Extensive home range of both females and males overlap [13] and probably suggests no territorial behavior [4].


Threats

Threatened mainly due to habitat loss [1]. A considerable amount of its habitat has been destroyed and fragmented by urban and agricultural development in southern California [2].


Orange-throated whiptail sources