Life Histories and Pinniped Reproduction Quiz

Pinniped Reproduction and Breeding Strategies

• Pinnipeds are annual breeders, except the Australian sea lion, which breeds year-round
• Longitudinal studies are conducted using long-term mark-recapture methods on species such as Weddell seals, Northern Elephant Seals, and Grey seals
• Cross-sectional studies, often commercial harvests, provide limited information, mainly on females attending to offspring on land
• Pinnipeds employ life history strategies such as capital breeding (using endogenous reserves for milk production) and income breeding (offsetting costs by foraging)
• Individuals have the option of reproducing annually, but may not breed every year due to the cost versus benefit of breeding
• Polygyny is common among pinnipeds, with large body size, sexual dimorphism, and gregarious breeding
• Female pinnipeds have a reproductive system similar to terrestrial carnivores, while males have a unique embryonic diapause during gestation
• The duration of lactation in pinnipeds depends on the stability of habitat and vulnerability to predation, with weaning being sudden for phocids and gradual for otariids
• Land-breeding phocids have longer lactation periods than ice-breeding phocids
• Land-breeding otariids have lactation periods lasting several months to one year, with foraging trips varying between fur seals and sea lions
• Pup survival in colonial species depends on polygynous breeding practices, and maternal recognition through vocal and olfactory signatures
• Manatees and dugongs have different sexual maturity, gestation, and weaning periods; they use tusks for lekking and are disputed in terms of dugong sexual maturity