Food consumption and growth of California sea lions (Zalophus californianus californianus)
Publication Type: |
Journal Article |
Year of Publication: |
2000 |
Authors: |
R. A. Kastelein, N. M. Schooneman, N. Vaughan, P. R. Wiepkema |
Publication/Journal: |
Zoo Biology |
Publisher: |
Inc., John Wiley & Sons |
Keywords: |
energetics, lactation, pinnipeds, pup, reproduction, sexual dimorphism, weaning |
ISBN: |
1098-2361 |
Abstract:
Abstract 10.1002/1098-2361(2000)19:2<143::AID-ZOO5>3.3.CO;2-F The daily food consumption of 26 California sea lions at the Harderwijk Marine Mammal Park was recorded. Average annual food consumption of males increased with age to stabilize at approximately 4,000 kg/year by the age of 10 years. Females showed a rapid increase in average annual food consumption until they were 3 years old. Thereafter, females housed outdoors averaged 1,800 kg/year, whereas those housed indoors ate approximately 1,400 kg/year. Between the ages of 4 and 7 years, the food intake of males began to fluctuate seasonally, decreasing between May and August. The low food intake in summer was associated with an increase in aggressive behavior. Seasonal fluctuation in the food intake of non-reproductive females was negligible. Between the ages of 6 and 8 years, many females began to reproduce successfully. Pups were born in May and June. The females’ food intake decreased approximately 3 days before birth and ceased the next day. Feeding resumed the day after birth, and by 2 days after birth, it had usually returned to normal. On average, female intake increased in the year of conception, the year of birth, during which the pup was suckled for 6 months, and the following calendar year, during which the pup was weaned. Pups began to eat fish at approximately 11 months of age. When forcefed, they were fully weaned within 2 to 23 days. Male weight and body length increased until approximately 20 years of age. Females increased in body length until 6 years and in weight until approximately 13 years of age. The relationship between standard body length and body weight is given. The heavier an animal is, the lower is its food intake as a percentage of body weight. Zoo Biol 19:143–159, 2000. © 2000 Wiley-Liss, Inc.