Circadian and ultradian activity rhythms in manatee (Trichechus manatus manatus) in captivity

Abstract

In this study, we show temporal organization of activity patterns in larger temporal series recording. The objective of this study was to determine the temporal pattern of the rest-activity rhythm in manatee (Trichechus manatus manatus) in captivity. Activity recordings were programmed from August 2010 to September 2011 with actimetry devices, and behavior recordings were conducted in dry and rainy seasons. We showed that the marine manatee presents a complex temporal organization, in which the rest-activity rhythm comprises several frequencies with a predominant circadian component and multiple ultradian components. Our results indicate that the animals were more active during the day with respect to the night. The temporal organization of this cycle entails multiple frequencies that include ultradian rhythms, which may be expressions generated by physiological needs, such as food availability and thermoregulatory requirements. These patterns should be taken into consideration for future studies of biological rhythms in manatee.

Keywords:

• marine mammals
• actimetry
• rest-activity
• activity patterns
• behavior

Acknowledgements

We are grateful to the postgraduate section of the Institute of Neuroethology of this same university. We thank the laboratory Chronoecology and Human Ethology of INPRFM. We thank the authorities and technical staff of the Aquarium of Veracruz who allowed us to conduct this research in their facilities. We appreciate the collaboration of the engineers of the University of Veracruz with the actimeter equipment and the help of José Carlos Sánchez Ferrer in the statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the CONACyT (Consejo Nacional de Ciencia y Tecnología) with a scholarship [No. 290564] and by the Area of Agriculture and Livestock of the University of Veracruz.