Winter body fat, food consumption and nonshivering thermogenesis of representative spontaneous and facultative hibernators: The white-tailed prairie dog and black-tailed prairie dog

Abstract

1. 1. White-tailed prairie dogs are spontaneous hibernators while black-tailed prairie dogs do not hibernate unless severely deprived of food and water at low ambient temperatures. 2. 2. Contrary to what has been thought about spontaneous and facultative hibernators, both of these species in this study had similar body fat content when trapped in the field. Also, both species had an identical nonshivering thermogenic response when tested at mid-winter. 3. 3. White-tailed prairie dogs became spontaneously anorexic during late fall and underwent bouts of torpor while the black-tailed prairie dogs continued to eat throughout the winter and only rarely entered torpor. 4. 4. In spite of their different thermoregulatory and eating behaviors, both species exhibited the same body weight profiles through the fall, winter and spring. 5. 5. It is concluded that the lack of spontaneous hibernation in the black-tailed prairie dog may be a derived characteristic, divergent from the condition in the ancestral stock. However, the genetically controlled ‘sliding’ body weight set-point remains similar to that of the hibernating white-tailed prairie dog, a representative of the presumed ancestral condition.