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Introduction:

Edward Cope described the Giant Horned Lizard (GHL) in 1864. The species portion of the scientific name is asio, which means horned owl. This species of Phrynosoma comes from the areas of Mexico that have moderate temperatures year round, so they do not require cold winter temperatures. GHLs inhabit semi-tropical locations with cacti. These areas in Mexico have distinct wet and dry periods, of which the Giant Horned Lizards seem to base their activity around.

header=[<center>Distinguishing Body Features. Photos by Jeff Judd</center>] body=[<img src='p_data/species/asio/JJudd/image1.jpg'>]delay=[600]

Description:

GHLs have a snout to vent length of five inches, with a total length of eight inches. Giant Horned Lizard males are distinguished from females by the presence of an enlarged postanal scales. The general body structure of Phrynosoma asio is very long, moderately wide, and moderately flat with a long rounded tail. There are two rows of distinct dorsal spines that run down the outer edges of the back and tail. There are two rows of distinct abdominal fringes are on each side of the body.

header=[<center>Tropical scrub habitat in Guerrero, Mexico</center>] body=[<img src='p_data/species/asio/JJudd/image3.jpg'>]delay=[600] header=[<center>GHL basking outside</center>] body=[<img src='p_data/species/asio/JJudd/image4.jpg'>]delay=[600]

Habitat:

The habitat for GHLs includes rocky hillsides, and dry drainages, in tropical, deciduous forests and arid, tropical scrub at elevations between 0 and 4900 feet.

header=[<center>Male and Female GHL</center>] body=[<img src='p_data/species/asio/JJudd/image5.jpg'>]delay=[600]
header=[<center>GHLs locked in mating</center>] body=[<img src='p_data/species/asio/JJudd/image6.jpg'>]delay=[600]

Reproduction:

GHLs mate in May and June. During this time, there will be an increase of displays that include tongue licking, head bobbing, arm waving and tail wagging. The male will start by chasing the female around. After he catches her, he mounts her while grasping her nuchal folds on the side her neck and swings his tail under hers until the bases meet. They then will begin copulation, lasting from two to four minutes.

Number of Offspring is: 10 to 28
Mating Period is: from May to June
Length of Gestation is: 60 to 70 days
Length of Incubation is: 70 to 90 days
Hatchlings Emerge: September - November

Activity Periods:

Giant Horned Lizards are mainly active during the mornings and late afternoons June through October. At night, they seek refuge in branches of plants or under objects. Most Giant Horned Lizards will seek shelter and become inactive during November through April, coinciding with the dry season of their native habitat.

Diet:

Natural diet includes: ants, termites, beetles and their larva, grasshoppers, flies, spiders, and crickets. Ants are an important part of this diet. Studies on wild GHLs show that ants make up roughly thirty-one percent of the natural diet by volume.

Range:

Giant Horned Lizards can be found in each of the following areas: Jalisco, Colima, Guerrero, Oaxaca, and Chiapas in Mexico, and Huehuetenango in Guatemala.