The alligator lizard, commonly represented by species within the genus Elgaria, is a prevalent reptile species found across the diverse habitats of Western North America, ranging from the Pacific Coast of Washington down to Baja California. These lizards are adaptable and often occupy areas from sea level up to high elevations in mountain ranges, thriving in environments like chaparral, woodlands, and even suburban gardens. They are best described as generalist predators, meaning their diet is highly opportunistic and determined primarily by what prey is available and catchable within their immediate environment.
Primary Invertebrate Prey
The core of the alligator lizard’s diet consists of numerous invertebrates, which are the most frequently encountered food items in their foraging habitats. Hard-bodied insects, such as ground beetles, grasshoppers, and crickets, make up a significant portion of their intake. Their sharp teeth and strong jaws are an adaptation that allows them to effectively crush the tough exoskeletons of these insects.
They also readily consume soft-bodied invertebrates, including various insect larvae like hornworms and wax worms, which provide concentrated energy. Spiders, centipedes, and scorpions are regularly captured, though scorpions are eaten less frequently and with caution. Mollusks are a particularly important food source, with snails and slugs being consumed often. The lizard’s robust jaw structure is especially useful for breaking down the protective shells of snails, giving them access to a nutrient-dense food source.
Occasional and Supplemental Food Sources
While invertebrates form the bulk of their meals, alligator lizards supplement their diet with a range of larger and less common prey items. Small vertebrates, particularly other lizards, are sometimes preyed upon, with juvenile Western Skinks being a notable example found in their stomach contents. They are also known to consume newborn rodents, such as baby mice, when they are encountered.
The consumption of eggs is an opportunistic feeding behavior, with some reports suggesting they may eat bird or reptile eggs if they find a nest. Cannibalism is also a documented occurrence in the wild, where larger adults will prey on smaller or juvenile alligator lizards. Furthermore, while they are primarily carnivorous, they may occasionally ingest plant matter, such as small fragments of stems, leaves, or fruit, likely consumed incidentally while striking at prey.
Hunting Strategy and Foraging Habits
The alligator lizard employs a combination of ambush and active foraging to secure its meals. They move slowly and stealthily through leaf litter and dense cover, relying on their cryptic coloration to remain unnoticed by potential prey. Prey movement is a major stimulus for initiating a strike, and the lizards use a characteristic head-bobbing motion to help them judge the distance and size of targets.
Once prey is identified, the lizard approaches cautiously, often investigating the item with its tongue to gather chemical cues about edibility. The final attack is a swift, downward strike, grasping the prey firmly in its jaws. If the prey struggles, the lizard may resort to aggressive tactics, such as twisting or battering the animal against the ground to subdue it before swallowing it whole.