Tonto National Monument is home to 15 species of lizards; only the Gila Monster is venomous. Learn about each of these species below.
Clark's Spiny Lizard
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Clark's Spiny Lizard
Sceloporus clarkii
Body Length: 3 - 5"
Diet: Insects and some plant parts
Clark's spiny lizards are large, stocky lizards with large, pointed, keeled, and overlapping scales. They are often gray with blue accents on their body and tail and dark bands on their forearms.
These day-active lizards often flee into trees when they sense danger. If you chase after one, it may dart to the opposite side of the tree. If you circle around the trunk for a better view, the lizard will move to the opposite side again. The longer this done, the higher the lizard is likely to climb.
Desert Night Lizard
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Desert Night Lizard
Xantusia vigilis
Body Length: 1 1/2 - 2 3/4"
Diet: Arthropods such as insects and spiders
These small, soft-skinned lizards have small dark specks on light tan skin. Night lizards are secretive lizards, living under downed vegetation and in rock crevices. They regulate their body temperature by basking under sun-warmed rocks. They were once thought to be extremely rare, and their presence at Tonto National Monument is noteworthy.
Desert Spiny Lizard
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Desert Spiny Lizard
Sceloporus magister
Body Length: 3 1/4 - 5 1/2"
Diet: Insects, lizards, and sometimes plant parts
This large, stocky lizard has pointed and overlapping scales. They are gray or brown in color with a large purple patch or bar on their back. The lack of black bands on its front legs distinguish the desert spiny lizard from the Clark's spiny lizard. This day-active lizard is often seen on rocks or other sunlit places.
Gila Monster
NPS Photo/ J Schofer
Gila Monster (Venomous)
Heloderma suspectum
Body Length: 9 - 14"
Diet: Eggs, small mammals, nesting birds, and carrion
The Gila monster is a symbol of the Sonoran Desert. It is a large, stout bodied lizard with a short, fat tail. Their markings consist of black bands on a yellow background. They are the largest lizard in the United States, and one of only a few venomous lizards in the world. Learn more about the Gila Monster.
Gila Whiptail
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Gila Spotted Whiptail
Aspidoscelis flagellicauda
Body Length: 2 1/2 - 3 3/4"
Diet: Termites, spiders, and other arthropods
This slim, brown to black lizard has a long, thin tail, and a slim, pointed snout. Their body is marked with six light yellow or cream stripes and a few relatively light spots. These spots are visible between the stripes.
Both the Gila spotted whiptail and Sonoran spotted whiptail share an uncommon trait: parthenogenesis, or development of the young from unfertilized eggs. There are no males in either species- only females! Scientists are still not sure how these all-female whiptails originated, and how a number of separate but very similar species are related.
Great Plains Skink
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Great Plains Skink
Plestiodon obsoletus
Body Length: 3 1/2 - 5 1/2"
Diet: Insects, spiders, mollusks, and other lizards
Great Plains skinks are easily recognized by their shiny scales and alert, agile appearance. The base coloration is tan or cream with dark crescent marks on each scale creating a net-like pattern over their body.
This lizard lays up to 12 eggs in late spring. During the one-to-two month incubation period, the females guard their eggs, a somewhat uncommon behavior for a reptile. Young skinks are jet black at hatching, with a bright blue tail. This color fades as they age, and adults are uniformly a less vivid color, usually greenish-brown to gray.
Greater Earless Lizard
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Greater Earless Lizard
Cophosaurus texanus
Body Length: 1 7/8 - 3"
Diet: Insects
This lizard is gray or tan with long, slender limbs and a flattened tail. Both males and females have two black crescents along the sides of their bellies near their hind legs, and black bars on the undersides of their tails. Males are blue, green, or yellow on their sides. During breeding season, females will develop a pink throat patch. This lizard lacks external ear openings; it is believed this may allow easier burrowing in sandy habitats.
Madrean Alligator Lizard
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Madrean Alligator Lizard
Ekgarua kingii
Body Length: 3 - 5"
Diet: Insects and scorpions
This large lizard has a long body, small limbs, and a long, thick tail. They resemble snakes to some extent. The Madrean alligator lizard has armor-like scales and a fold in the skin that runs the length of their body, which may allow the relatively inflexible body to expand during breathing, after feeding, or when the female is carrying eggs.
These day-active lizards are not commonly seen at Tonto National Monument. They are often heard before they are seen, rustling through dry leaves on the ground.
Regal Horned Lizard
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Regal Horned Lizard
Phrynosoma solare
Body Length: 3 - 5"
Diet: Primarily ants
This exceptionally flat and wide lizard has a short tail and a crown of flattened, dagger-like horns radiating from the back of the head. The horns are primarily used for defense against predators.
This lizard can be active at any time of the year but winter is usually restricted to unseasonably warm days. When threatened, it may squirt blood from its eyes. This blood may have a foul taste designed to deter predators.
Side-blotched Lizard
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Side-blotched Lizard
Uta stansburiana
Body Length: 1 1/2 - 2 3/8"
Diet: Insects, scorpions, spiders, and other arthropods
This commonly seen small lizard is orange-tan to gray-brown with dark marks, "side blotches", on the lower side of the body just behind the forelimb. Males often have bright turquoise speckling on the tail, back, and upper surfaces of the hind legs. Females lack this blue speckling but have light stripes.
This day-active lizard may be found any time of the year, and it is distributed across most of Arizona.
Sonoran Collared Lizard
NPS Photo/ M. Stewart
Sonoran Collard Lizard
Crotaphytus nebrius
Body Length: 3 - 4 1/2"
Diet: Insects, lizards, and plants
This medium-sized lizard has a large head and two distinct, black collar markings on the neck. Their body color ranges from brown to an almost emerald green, with white spots on the neck, and a bold yellow on the head. Unlike other lizards, they can not cast off and regenerate their tails.
Collared lizards are day-active, or diurnal, and can be very conspicuous when present. They are often seen basking atop large rocks in the mid-morning sun.
Sonoran Spotted Lizard
NPS Photo/ M. Stewart
Sonoran Spotted Whiptail
Aspidoscelis sonorae
Body Length: 2 1/2 - 3 3/4"
Diet: Termites, spiders, and other arthropods
These small, slim, brown lizards have a long, thin tail, and a slim pointed snout. Their body is marked with six yellow stripes and relatively few light spots. The area between the two central stripes lacks spots.
Both the Gila spotted whiptail and Sonoran spotted whiptail share an uncommon trait, parthenogenesis, the development of the young from unfertilized eggs. There are no males in either species- only females! Scientists are still not sure how these all female whiptails originated, and how a number of separate but very similar species are related.
Tree Lizard
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Tree Lizard
Urosaurus ornatus
Body Length: 1 1/2 - 2 1/4"
Diet: Insects and spiders
This small, slim lizard is gray or tan with a pattern of thin, dark lines on the top of their head. Their body markings are variable but usually consist of dark, irregularly shaped blotches. Males have two large, blue patches on their belly and another on their throat. During the breeding season male tree lizards can be seen out doing "push-ups" with all four legs. These push-ups flash the male's bright blue undersides, advertising his availably to potential mates.
This day-active lizard is most commonly seen on boulders and cliffs, including the cliff dwelling walls.
Western Banded Gecko
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Western Banded Gecko
Coleonyx variegatus
Body Length: 2 - 3"
Diet: Arthropods such as insects and spiders
This small, yellow lizard with reddish brown patterns on the body and tail are sometimes confused with young Gila monsters. However, geckos are much smaller, more delicate, and not venomous. A yellow line loops from the corner of their eye around the back of their head to their other eye like an eyeglass strap. Behind this loop is a broad, reddish brown collar.
Like a number of other lizards, geckos readily lose their tails to predators. This detached tail continues to wriggle long after the rest of the lizard has made its escape, thus confusing the predator. Though they may be active underground during the day, western banded geckos and desert night lizards are the only truly nocturnal lizards at the Monument.
Western Whiptail
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Western Whiptail
Aspidoscelis tigris
Body Length: 2 3/8 - 4 1/2"
Diet: Insects, spiders, scorpions, and lizards
This medium-sized, slim lizard is orange-brown with a long, thin tail and a slim, pointed snout. Their body has dark marbling, light spots, and faint, light stripes. As the whiptail ages, the tail becomes brown, the stripes fade, and the spots often merge together.
This alert and fast-moving lizard spends most of its waking hours in motion foraging and moving between the sun and shade.
Zebratail Lizard
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Zebratail Lizard
Callisaurus draconides
Body Length: 2 1/2 - 4"
Diet: Insects, spiders, other lizards, and plants
This tan, medium-sized lizard has long, slender limbs and a flattened tail. Two rows of small gray-brown spots run down the middle of its back. The back of each thigh is marked with a distinct, dark, horizontal line and their tail is marked with gray-brown bands that become black on the underside where they contrast with a white background.
This heat tolerant, day-active lizard often remains active throughout mid-day when high temperatures force other lizards to seek shelter. When approached by a predator it often curls and wags its tail over the back exposing the black and white "zebra stripes"
