“…Because female tegus remain with their egg clutches throughout the incubation period (33) and lepidosaurs are the sister taxa to birds and other archosaurs, the results also lend support to the parental care model of endothermy in which enhanced parental metabolic capacity could be selected to facilitate increased nest temperature or enhance nest thermal stability, which are known to speed up or alter the developmental rates of embryos in reptiles (13). The reason male tegus also exhibit these changes in temperature could be common seasonal hormonal (for example, estradiol, leptin, or thyroid hormone) surges with pyrogenic potential (48)(49)(50), that sperm production and gonadal regrowth are energetically expensive (18), that spermatogenesis requires elevated temperatures (37,38), that the rapid rise in testosterone following a period of hibernation, leads to intense androgenic effects (28) such as seasonal changes in secondary sexual morphologies (31), or simply that the genetic processes supporting maternal endothermy are shared in offspring of both sexes and not linked to sex chromosomes (13).…”