The Sand Lizard (Lacerta agilis) is a small reptile native to the Eurasian continent, ranging from Britain eastward to Lake Baikal in Russia. This diurnal species prefers specialized habitats, such as coastal dunes, heathlands, and dry grasslands. These environments offer open, sunny areas with sandy soil necessary for thermoregulation and egg incubation. The Sand Lizard is a carnivore that specializes in invertebrates.
Primary Prey and Invertebrate Focus
The Sand Lizard’s diet is composed almost exclusively of arthropods, classifying them as opportunistic insectivores. They consume a wide array of prey items based on their availability in the environment. The largest portion of their diet consists of beetles (Coleoptera), which are a substantial food source. Other favored invertebrate groups include orthopterans, such as grasshoppers and crickets, and spiders (Arachnida). They also consume the larval and adult stages of butterflies and moths (Lepidoptera). While they consume what they encounter, they specifically avoid ants (Formicidae) despite the ants’ high abundance. This selective foraging is likely due to the ants’ chemical defenses or tough exoskeletons.
Hunting Strategies and Foraging Behavior
The Sand Lizard employs a combination of hunting methods. It often acts as an ambush predator, using a sit-and-wait strategy early in its active period. This involves remaining motionless before launching a rapid burst of speed to capture unsuspecting prey. The lizard also engages in active foraging, moving frequently but pausing often to scan the area for movement. They frequently use tongue-flicking, a chemosensory behavior, to detect and identify potential prey by sampling chemical cues from the ground and air. Proper body temperature is a prerequisite for a successful hunt, as physical performance is linked to the heat they absorb. By basking in sunny spots, the Sand Lizard elevates its internal temperature, allowing for the quick movements necessary to chase and subdue prey.
Dietary Changes from Juvenile to Adult
The nutritional requirements and physical capacity of the Sand Lizard change significantly as it matures, leading to distinct differences between juvenile and adult diets. Juvenile diets are constrained by smaller body size and jaw strength, requiring them to target much smaller prey items. Young lizards primarily consume tiny invertebrates, such as aphids and small spiders. As the lizard grows, there is a positive correlation between its body size and the diversity of prey it can consume. Adults are capable of tackling larger, more robust insects, including fully grown beetles and orthopterans. Seasonal changes also affect the adult diet, with the largest daily food intake occurring in mid-summer (typically July). This peak feeding correlates with the abundance of insects and the need to build energy reserves before hibernation.