Behavior of Juvenile Lizards <i>(Iguana iguana) </i>in a Conflict between Temperature Regulation and Palatable Food

Abstract

Juvenile green iguanas were placed in a situation of conflict between two motivations: a thermoregulatory drive and the attraction of a palatable bait. To be able to reach the bait (lettuce), they had to leave a warm refuge, provided with standard food, and venture into a cold environment. In experiment 1 the time interval between sessions with bait, ranging from 1 to 8 days, had no effect on the duration of stay on the bait. This result shows that the lettuce was not a necessary food, deprivation of which would have had to be compensated for. In experiment 2 as the ambient temperature at the bait decreased the lizards spent less time feeding on lettuce, and they visited the bait less frequently. This result shows that the lizards traded off the palatability of the bait with the disadvantage of the cold. These findings support the hypothesis that a common currency makes it possible for lizards to compare two sensory modalities.

Dimensions of Animal Consciousness

“…Similar experiments have been done on iguanas (Iguana iguana) [33] and hermit crabs (Pagurus bernhardus) [34,35], with similar results. What is lacking, so far, is interspecies comparisons of the sophistication of the evaluations being made by different species and investigations of how sophisticated the evaluations need to be to indicate conscious affect.…”

Role of the blood–brain barrier in the evolution of feeding and cognition

“…Primates have been found to take recent trends in temperature and solar radiation into account in deciding whether to revisit trees for newly ripened fruit 48 . Iguanas balance acquisition of food located in cold areas against the disadvantage of leaving a warmer area with less palatable food 49 . In storing food for future use, mountain chickadees alter their caching strategies when potential pilferers are in the area 50 .…”

To heat or to save time? Thermoregulation in the lizardZootoca vivipara(Squamata: Lacertidae) in different thermal environments along an altitudinal gradient

“…This finding is consistent with the "static concept of thermoregulation", i.e., lizards thermoregulate carefully whenever possible (Bogert 1949), and the suggestion of Dunham et al (1989) that "requirements for thermoregulation, because of immediate effect of temperature on organism biochemical functions and physiological performance, should usually have precedence over the requirements of foraging and maintaining social status". These views are also supported by the fact that some lizards, including Z. vivipara, thermoregulate carefully despite the various costs involved under controlled laboratory conditions (Avery 1976(Avery , 1985Cabanac 1985;Balasko and Cabanac 1998). The lack of thermoregulatory response to a shift in time costs may result from an unknown relationship between the currency used, time, and the ultimate currency of costbenefit models, fitness.…”