Active during the day, the desert monitor emerges from its burrow in the early morning, and basks in the sun at the entrance in order to raise its body temperature (2). When sufficiently warmed, it begins to forage, using its long forked tongue to detect chemical cues in the air that help it to track down prey (2) (4). Once its quarry has been sighted, the desert monitor either rushes at it directly, or stalks it to within a few metres, before sprinting forwards. Prey is dispatched by biting the neck, which disrupts breathing, and also by violently shaking the animal in its jaws, after which it is swallowed whole (2). Desert monitors are opportunistic predators, and employ an impressive range of skills in the pursuit of food, including tree-climbing, swimming and digging (2) (3). Their diet includes small mammals, birds, eggs and insects, and they will even tackle challenging prey such as hedgehogs, tortoises and venomous snakes. During a single day, desert monitors range over large distances, usually between five and six kilometres, returning to their burrow before sunset (2).
Although the desert monitor is a solitary species, individuals may occur in relatively high densities over a small area, which is described as a “settlement”. Within settlements, the individuals tolerate each other’s presence, although ritualised combat may occur to assert dominance. Desert monitor mating occurs over a 15 to 20 day period during the first two-thirds of June. Males typically locate a mate by following tracks in the sand, but while tracking may occur over days, and can range over many kilometres, it is frequently unsuccessful. If the male does catch up with the female, he may follow her closely for some time before copulation occurs (2).
Egg-laying generally occurs from late June to early July, and is preceded by the female digging a burrow with two shafts, one leading to a chamber which the female inhabits, and the other to a chamber in which a clutch of between 10 and 20 eggs is laid. After depositing the clutch, the female tightly packs the shaft leading to the eggs with sand, and then remains in the vicinity of the burrow to defend it from other desert monitors. In early October, after an incubation period of around 110 days, the eggs hatch, but the young do not yet attempt to dig to the surface. Like adult desert monitors, they hibernate through the winter, emerging from the subterranean chamber in the following spring (2).