claimed to grow much longer. A specimen measuring reportedly was caught in Konedobu by Dr. F. Barker. Claims that some specimens considerably exceed such lengths are so far unsupported. Claims of V. salvadorii attaining large weights also are unverified; the species is much more slender than Komodo dragons of comparable length. The typical reported length of this species is less than with a matching body mass of about . Ten adult specimens were found to weigh only at a length of , so even the aforementioned weight is fairly optimistic for this species. However, these specimens were not fully mature since wild caught specimen have been known to grow over and breeders of this lizard have estimated that wild specimens can weigh up to . The average size of V. salvadorii caught in one study was with a weight of , but these must have been young specimens. Varanus salvadorii has mammal-like aerobic abilities; a positive pressure gular pump in the animal's throat assists lung ventilation. Unlike most lizards that cannot breathe efficiently while running, because of Carrier's constraint, the gular pump of monitor lizards enables them to overcome the effect of one lung at a time being compressed by their running gait. The evolutionary development of the gular pump is functionally analogous to that of the diaphragm in mammals, which ventilates the lung independently of locomotion. V. salvadorii may be the species that achieves the greatest running endurance as a result of its gular pump. Investigation supports the idea that gular breathing is an evolutionary development that masks the effect of Carrier's constraint. Behavior V. salvadorii is a highly arboreal lizard. It can hang onto branches with its rear legs, and occasionally use its tail as a prehensile grip. The primary function of the tail, however, is as a counterbalance when leaping from branch to branch. As in some other Varanus species, the tail also may be used for defense, as captive specimens may attempt to lash keepers with their tails. This species occasionally is seen in the pet trade, but has a reputation for aggression and unpredictability. Although they are known to rest and bask in trees, they sleep on the ground or submerged in water. These monitors rise up on their hind legs to check their surroundings, behavior that also has been documented in Gould's monitors (V. gouldii). They are known to exhibit a warning posture, in