Concept explainers
The Return of the Elephant Seals
Female elephant seals reach sexual maturity at 3 to 4 years of age and produce one pup each year. Elephant seals breed harem-style, with a single large bull typically monopolizing and inseminating 30 to 100 females. Although males reach sexual maturity at 5 to 7 years of age, few are powerful enough to acquire a harem until 7 to 10 years of age; some are never able to compete. Further, although the maximum life span is about 20 years for females and 15 for males, only about 1 in 5 survives beyond 5 years of age. These factors combine to produce a biotic potential of about 12% per year. But elephant seal populations virtually never reproduce at their biotic potential. Why not?
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Biology: Life on Earth with Physiology (11th Edition)
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