Birth to weaning in 4 days: remarkable growth in the hooded seal, Cystophora cristata
A brief lactation period with rapid neonatal weight gain may be adaptive for seals breeding on unstable pack ice. We studied the duration of lactation and growth of known-age pups of the hooded seal, Cystophora cristata, on the pack ice off Labrador. Mean body weight of pups increased from 22.0 kg a...
| Published in: | Canadian Journal of Zoology |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1985
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/z85-424 http://www.nrcresearchpress.com/doi/pdf/10.1139/z85-424 |
| Summary: | A brief lactation period with rapid neonatal weight gain may be adaptive for seals breeding on unstable pack ice. We studied the duration of lactation and growth of known-age pups of the hooded seal, Cystophora cristata, on the pack ice off Labrador. Mean body weight of pups increased from 22.0 kg at birth (n = 21) to a maximum of 42.6 kg on day 4 (n = 11) and then declined. On the basis of maternal absence, weight change, gastric contents, and clarity of blood serum, we conclude that pups are weaned 4 days after birth (range, 3–5 days). This is the shortest lactation period known for any mammal. Tagged pups captured on sequential days gained on average 7.1 kg per 24 h from the day after birth to weaning. Maternal effort supported a relative rate of weight gain (145 g∙kg maternal weight −0.75 ∙day −1 ) that is 2.5–6 times that of other phocids. By combining a large birth weight with rapid neonatal weight gain, hooded seals achieve a weaning weight comparable to other phocids in one-third to one-tenth the amount of time after birth. |
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