acta ethologica

, Volume 22, Issue 1, pp 67–71 | Cite as

Living on the edge: thermoregulatory behaviour of South American sea lions, Otaria flavescens, at the northern limit of their Atlantic distribution

  • Carme Tuneu-Corral
  • Diana Szteren
  • Marcelo H. CassiniEmail author
Short Communication


Terrestrial reproduction presents a thermoregulatory challenge for marine mammals, especially in a context of global warming. Pinnipeds, especially otariids, differ from other marine mammals in that most reproductive processes occur on land. Rocky rookeries rarely provide thermoregulatory resources (shade, pools and wet sand), so pinnipeds reduce thermal stress through thermoregulatory behaviour such as flipper exposure, flipper movement and maintenance of individual distance. Our objective was to analyse climate correlates of thermoregulatory behaviour of Southern sea lions Otaria flavescens in a colony located at the warmest end of its northern distribution on the Atlantic coast of South America. We conducted summer behavioural observations of juveniles/sub-adult (less than 150 kg) and adult (300 kg) males in the Cabo Polonio rookery, Uruguay. Solar radiation and humidity were positively correlated with thermoregulatory behaviour of sea lions, while ambient temperature had a marginal effect and wind speed had no significant effect. There were no statistically significant differences between age classes in thermoregulation activity. These and previous results on thermoregulatory behaviour of pinnipeds open the possibility that pinnipeds can be limited in abundance or distribution if climate change alters solar radiation in terrestrial rookeries during the breeding season.


Sea lions Southwestern Atlantic Ocean Global warming Thermoregulation 



We thank Gonzalo Picasso, Director of Cabo Polonio National Park, for granting us all permissions for working and collecting the necessary data in the natural reserve. We also thank the rangers group and lighthouse keepers group of the park for the excellent treatment received.

Compliance with ethical standards

All applicable international, national and/or institutional guidelines for the care and use of animals were followed.

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© ISPA, CRL 2018

Authors and Affiliations

  • Carme Tuneu-Corral
    • 1
  • Diana Szteren
    • 2
  • Marcelo H. Cassini
    • 3
    Email author
  1. 1.Universitat de BarcelonaBarcelonaSpain
  2. 2.Laboratorio de Zoología Vertebrados, Departamento de Ecología y Evolución, Facultad de CienciasUniversidad de la RepúblicaMontevideoUruguay
  3. 3.Laboratorio de biología del Comportamiento (IBYME)Universidad Nacional de LujánBuenos AiresArgentina

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