Predation risk modulates diet-induced obesity in male C57BL/6 mice.
OBJECTIVE
In this study, the behavioral and physiological changes induced by experimentally varying the risk of predation in male mice fed a high-fat diet were examined. In particular, the study aimed to assess whether the risk of being predated modulates the body weight gain, providing an ecological context for the obesity resistance observed in many species of small mammals.


METHODS
Body weight, food intake, physical activity, and core body temperature of 35 male C57BL/6 mice were monitored for 20 days, while feeding a high-fat diet. A third of the animals were exposed to elevated risk of predation through exposure to the sounds of nocturnal predatory birds, and these were compared to animals exposed to a neutral noise or silence.


RESULTS
Male mice exposed to predation risk had significantly lower weight gain than the neutral or silent groups. Reduced food intake and increased physical activity were the main proximal factors explaining this effect. The risk of predation also induced changes in boldness.


CONCLUSIONS
This study provides evidence supporting the role of predation risk on body weight gain of small mammals.
CESAM-Center for Environmental and Marine Studies, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.
Rita I
RI
Monarca
CESAM-Center for Environmental and Marine Studies, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.
Maria
M
da Luz Mathias
Institute of Zoology, Chinese Academy of Sciences, Chaoyang, Beijing, China.
DeHua
D
Wang
State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, China.
John R
JR
Speakman
D000818:Animals; D059305:Diet, High-Fat / Q000009:adverse effects*; D004435:Eating / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000209:etiology*; D011235:Predatory Behavior / Q000502:physiology*; D015430:Weight Gain / Q000187:drug effects