Strategies Adopted by Juvenile Lizards Foraging in a Cold Environment

Abstract

Juvenile Tupinambis teguixin were placed in a conflicting situation: feeding vs. cold environment. To feed they had to leave a warm refuge (Top 44–45 C) and go 1.5 m to where food was presented at an ambient temperature (Ta) varying from 25 to 0 C. When Ta was decreased, the lizards managed to eat a constant amount of food by modifying their behavior. They shortened the duration and increased the number of the meals, returning to the warm refuge between meals. In the cold, they left the food when their cloacal temperature dropped to about 32 C. After satiation, they maintained their cloacal temperature behaviorally between 34 and 38 C. The attempt to increase the lizards' drive for food by increasing the length of the fast preceding the access to food from I to 17 days did not result in any behavioral change during feeding. The only modification was a decrease in the amount eaten when the fast was shorter than 3 days. In a warm environment, when the intervals between feeding increased from I to 17 days, the lizards' main response was not an increase in food intake but, rather, a decrease in the growth rate and sloughing frequency.