Reptiles
Northern Alligator Lizard
Elgaria coerulea · also called northern alligator lizards
High in a cool Pacific Northwest forest where most lizards would already be too sluggish to hunt, a northern alligator lizard moves easily through the leaf litter, its tolerance for cold temperatures opening up habitat most reptiles simply cannot use.
Overview
The northern alligator lizard, Elgaria coerulea, is a cold-tolerant lizard native to forest and mountain habitat across the Pacific Northwest, from northern California through British Columbia. Its unusual comfort with cool temperatures and live-bearing reproduction make it one of the more physiologically distinctive lizards found in temperate North America.
A lizard that never needed the heat
While most lizards depend on warm conditions to stay active, the northern alligator lizard has instead adapted to thrive in genuinely cool forest habitat, an adaptation reflected directly in its unusual choice to bear live young rather than risk incubating eggs in cold soil.
Status
Least Concern — widespread and common across suitable forest and mountain habitat throughout the Pacific Northwest.
Northern Alligator Lizard: common questions
Why does the northern alligator lizard tolerate such cool conditions?
A northern alligator lizard tolerates notably cooler temperatures than most other lizard species, an adaptation that allows it to remain active at higher elevations and more northern latitudes across the Pacific Northwest, habitat conditions that would leave many other reptile species too cold to move effectively.
Why does giving birth to live young help this lizard?
The northern alligator lizard gives birth to live young rather than laying eggs, an adaptation that may improve reproductive success in a cooler climate, since carrying developing young inside the mother's body can provide more consistent warmth than eggs left incubating in cool soil.
What is the fold of skin along the northern alligator lizard's sides for?
A northern alligator lizard displays a distinct fold of skin running along each side of its body, allowing the torso to expand as needed, a feature particularly useful when a female is carrying developing young or after a large meal.
Where does the northern alligator lizard live?
The northern alligator lizard is native to forest and mountain habitat across the Pacific Northwest, from northern California through British Columbia, generally sheltering beneath logs, bark, and leaf litter.