Abstract
The purpose of this study was to examine the importance of body size and body composition as determinants of conditional mating tactics exhibited in male grey seals. We combined behavioral observations with measures of energy expenditure and success on 42 known-age individuals during the breeding seasons of 1997-2001 at Sable Island, Canada. Males with a large body mass arrived at the breeding grounds with more body fat and body energy and catabolized less body protein than smaller males. Males consumed 1.9 ± 0.2 MJ day -1, and those with a smaller percentage of body fat had higher rates of food energy intake. The amount of body energy on arrival was positively correlated with the duration of the breeding period. Males that exhibited the primary mating tactic of consortship were heavier, had absolutely more body fat and body energy, and sustained breeding longer than those males that did not exhibit the primary tactic. Amongst all males, body mass showed a quadratic relationship with the number of female consorts mated and the estimated number of pups sired. Thus, intermediate-sized males mated with the most consorts and achieved the highest success. Intermediate body size may be optimal during breeding due to greater agility in male combat. Body size was an important determinant of mating tactics used by male grey seals. A large body size provided an energetic advantage of greater endurance while an intermediate body size may provide greater competitive ability in acquiring consortships.
| Original language | English |
|---|---|
| Pages (from-to) | 541-549 |
| Number of pages | 9 |
| Journal | Behavioral Ecology |
| Volume | 16 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - May 2005 |
Bibliographical note
Funding Information:Institution, the Christensen Fund, the Canadian Department of Fisheries and Oceans, and the National Science and Engineering Research Council of Canada.
Funding Information:
We are very grateful to Suzanne Ambs, Debbie Austin, Carrie Beck, Suzanne Budge, Dave Coltman, Margi Cooper, Tom Hubbard, Steven Insley, Sara Iverson, Shelley Lang, Tyler Schulz, and Strahan Tucker for assistance in the field. Special thanks to Sara Iverson for making arrangements for the tritium and providing training and laboratory facilities for conducting the isotope analyses. We are also grateful for infrastructure support provided on Sable Island by Gerry Forbes. Two anonymous reviewers provided valuable comments on the manuscript and improved its quality. The study was supported by a Smithsonian Institution Graduate and Predoctorate Fellowship awarded to D.C.L. and funds from the Friends of the National Zoo, the Smithsonian
ASJC Scopus Subject Areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology