Regional variability in diving physiology and behavior in a widely distributed air-breathing marine predator, the South American sea lion (Otaria byronia).
J Exp Biol
; 219(Pt 15): 2320-30, 2016 08 01.
Article
em En
| MEDLINE
| ID: mdl-27247316
ABSTRACT
Our understanding of how air-breathing marine predators cope with environmental variability is limited by our inadequate knowledge of their ecological and physiological parameters. Because of their wide distribution along both coasts of the sub-continent, South American sea lions (Otaria byronia) provide a valuable opportunity to study the behavioral and physiological plasticity of a marine predator in different environments. We measured the oxygen stores and diving behavior of South American sea lions throughout most of its range, allowing us to demonstrate that diving ability and behavior vary across its range. We found no significant differences in mass-specific blood volumes of sea lions among field sites and a negative relationship between mass-specific oxygen storage and size, which suggests that exposure to different habitats and geographical locations better explains oxygen storage capacities and diving capability in South American sea lions than body size alone. The largest animals in our study (individuals from Uruguay) were the shallowest and shortest duration divers, and had the lowest mass-specific total body oxygen stores, while the deepest and longest duration divers (individuals from southern Chile) had significantly larger mass-specific oxygen stores, despite being much smaller animals. Our study suggests that the physiology of air-breathing diving predators is not fixed, but that it can be adjusted, to a certain extent, depending on the ecological setting and or habitat. These adjustments can be thought of as a 'training effect' as the animal continues to push its physiological capacity through greater hypoxic exposure, its breath-holding capacity increases.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Comportamento Predatório
/
Respiração
/
Leões-Marinhos
/
Ar
/
Mergulho
Limite:
Animals
País/Região como assunto:
America do sul
Idioma:
En
Revista:
J Exp Biol
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Estados Unidos