The Long-nosed leopard lizard is a relatively large North American lizard. It has granular dorsal scales that can be white, cream, or gray with irregular brown or dark gray spots along its body and head. Sometimes they have dark bars across their back. The tail also has dark bars across it. The male and female are different in appearance and both are capable of marked color changes. In its dark phase, the lizard's spots are nearly hidden and light crossbars become quite obvious on both the body and the tail. In the light phase, the opposite is true with the dominant color consisting of gray, pinkish, brown, or yellowish-brown hues. During the mating season, females develop reddish-orange spots and bars on their sides and underneath the tail when gravid while males develop pink or rusty wash on the throat, chest, and sometimes the body.
Long-nosed leopard lizards are found in the western part of the United States from Oregon to Idaho in the north, south to northern Mexico in Baja California, Sonora, Coahuila, and Zacatecas and Casa Grande, Arizona. In San Diego County, they occur east of the Peninsular Ranges within the Lower Colorado Desert. They prefer to inhabit arid and semiarid plains growth, like bunch grass, alkali bush, sagebrush, creosote bush, and other scattered low plants. The ground can be hardpan, sand, or even gravel with rocks that may often be used as basking sites. These lizards favor flat areas with open space for running and avoid densely vegetated areas.
Long-nosed leopard lizards are diurnal and are usually active all day when the weather is mild to warm. They are generally solitary, often seen sunning on small rocks along the roadside; after a period of basking, they begin active hunting and feeding. Long-nosed leopard lizards hunt their prey using stalking and ambush techniques. As ambush predators, they lie in wait in the shadows underneath a bush or small tree, where their spotted pattern blends, waiting for the prey to come within capture range. When prey is sufficiently close, they use a rapid pouncing movement to capture it in their strong jaws. Long-nosed leopard lizards are even able to jump up to 2 feet (60 cm) in any direction, including into the air, in order to catch their prey. When in danger, they use a defense mechanism known as "freeze" behavior; they run underneath a bush, flatten their body against the ground, and are motionless until the threat is gone. If the case is extreme enough, such as capture, Long-nosed leopard lizards will detach their tail. The speed and agility of these lizards are major contributors to their predatory success as well as their ability to evade predators. When running at rapid speeds they run with forelimbs raised. During the cold months, Long-nosed leopard lizards typically retreat to their burrows where they hibernate until spring.
Long-nosed leopard lizards are carnivores. They prey on small lizards, in addition to insects and sometimes rodents. They also eat smaller leopard lizards and their hatchlings when the opportunity arises.
The breeding season of Long-nosed leopard lizards extends from May to June. During this time no pair bond is formed between adults. The female lays a single clutch of 5-6 eggs usually in June or July. The eggs are laid in a burrow and hatch in the late summer months of July or August. The incubation period lasts between 5 and 7 weeks and young emerge in August.
The main threats to this species include the loss and degradation of their native habitat. This mainly happens due to the expansion of agriculture and urban development.
The IUCN Red List and other sources don’t provide the number of the Long-nosed leopard lizard total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.