Hibernation and its environmental and physiological correlates in the Himalayan lizard Agama tuberculatus

The Himalayan lizard, Agama tuberculatus, is a subtropical rock lizard and remains in hibernation In rock crevices for about 3 months/year. Adult anim als entered hibernacula within their home ranges In late November and mid D ecember. Juveniles were active upto mid January. Marked male lizards were s een to emerge in mid-March, and ail lizards of this species were active by early April. Experimental evidence indicates that perphas, decreasing/incre asing ambient temperatures are Possible cues for entrance into or emergence from hibernation. Data on physioligical correlates (e.g. abdominal fat-bod y wts., thyroid gland wts.) clearly show seasonal variations. Fat body depo sits are highest during the pre-hibernation period; this might provide ener gy for metabolic activities during hibernation. The, testes were found deve loped during the pre-hibernation period and were maintained during the hibe rnation period, when compared with thyroid hormone levels of Calotes versic olor, may perhaps be associated with lipolysis during hibernation and lipog enesis during other times.