As the short-tailed pygmy monitor is rarely seen, relatively little is known about its ecology (6). However, despite its secrecy this species can be common in places. Travelling only short distances, the short-tailed pygmy monitor hunts by ambush, feeding primarily on grasshoppers, spiders and beetles. Less frequent prey items include centipedes, scorpions, cockroaches, isopods, caterpillars, and insect larvae and pupae. The short-tailed pygmy monitor may also sometimes feed on other lizards such as Ctenotus species (6).
In central Australia, male short-tailed pygmy monitors reach sexual maturity at snout-vent lengths of around seven centimetres, usually when they are about ten months old. Females mature later at approximately 22 months old, at a snout-vent length of 8.5 to 9.3 centimetres (6). This species breeds in the spring between July and November, when females are developing their eggs and males have enlarged testes. Usually the female short-tailed pygmy monitor lays two to three eggs, but clutch sizes of four to five eggs have also been recorded. The eggs hatch from late January to February. Newborn short-tailed pygmy monitors have a snout-vent length of approximately 4.2 centimetres (7).
As in all monitors, the short-tailed pygmy monitor displays characteristic threat postures and behaviours such as hissing and lunging with the throat inflated (4).