Zoological Studies

Vol. 53, 2014

Thermoregulation in captive broad-snouted caiman (Caiman latirostris)

Luís AB Bassetti1*, Thiago S Marques1, Adriana Malvásio2, Carlos I Piña3 and Luciano M Verdade1

1Laboratório de Ecologia Isotópica, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Caixa Postal 96, Piracicaba, São Paulo 13416-000, Brazil
2Universidade Federal do Tocantins, ALCNO 14, Av. NS 15, s/n, Bloco III, sala 15A, Palmas, Tocantins 77010-970, Brazil
3Proyecto Yacaré, CICyTTP-CONICET Fac. CyT-UAdER/FCAl-UNER, Dr. Matteri y España, Diamante, Entre Ríos 3105, Argentina

Background: Crocodilians are ectothermic animals. For this reason, the environmental temperature has substantial effects on their physiology and behavior. The thermoregulatory behavior of these animals involves the selective use of different types of environments. This behavior enables them to reach the temperature level for their metabolic activities. This study aimed to determine the influence of sex, body size, and reproductive stage on the body temperature (Tb) of adult broad-snouted caiman (Caiman latirostris) in captivity. Thermal sensors were surgically implanted in the peritoneal cavity of 16 adult females and 4 adult males and programmed to register
Tb hourly during 6 months.
The diel Tb pattern of the broad-snouted caiman reflected the variation among the microenvironmental temperatures used by the species (water surface, pool bottom, and ground). The sex of the animals had influence on their Tb, but body size did not. Reproductive females had higher Tb than non-reproductive females during October to early November. It is possible that this difference is a result of the ovulation period of the species. Sick animals appeared to show behavioral fever.
Conclusions: The results of the present study suggest that several factors can affect the
Tb of adult broad-snouted caiman in captivity. Future studies should focus on the possible effect of thermoregulatory behavior on individuals' growth rate and reproductive performance.

Key words: Crocodilians; Body temperature; Ovulation; Social behavior; Behavioral fever; Reproduction.

*Correspondence: E-mail: luisbassetti@terra.com.br