Pinnipedia [Compatibility Mode]

Pinnipedia [Compatibility Mode] - 4/12/2010 32-35 species...

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4/12/2010 1 Order ‘Pinnipedia’ Now considered to be a suborder of the Now considered to be a suborder of the Order Carnivora Pinnipedia is an artificial grouping of carnivora from two families (sea lions, fur seals, and walrus descendents of bear-like ancestor; seals from mustelids) 32-35 species recognized Family Otariidae (Center of origin N. Pac.) 5 sea lions 10 fur seals Family Odobenidae 1 walrus Family Phocidae (Center of origin N. Atl.) 10 northern phocids 3 monk seals 4 Antarctic seals 2 elephant seals Main differences in furring & locomotion Otarioidea fore flippers have 5 rudimentary nails small external ear pinna Phocoidea fore flippers with 5 small distinct nails no external pinna distinct tail notch in tip of tongue scrotal testes dentition unspecialized upper incisors with distinct transverse groove tail enclosed in web of skin tip of tongue rounded testes internal dentition extremely specialized California sea lion Zalophus californianus distributed in North Pacific from Japan to Mexican coast Sexes dimorphic: Males 2-300 kg & 2-2.5 m in length: Females 50-100 kg & 1.5 - 2 m in length Sexes distributed differently outside of breeding season--males in cooler water Visual acuity in air is poor; hearing good California sea lion . .. Highly vocal, bark loudly, los lobos del mar in contrast to Steller’s sea lion, los leones del mar Two sea lions and 2 seals overlap spatially in California breeding range timing of 3 polygynous species is different Zalophus & Eumetopias both breed on San Miguel Is. Behavior of pinnipeds well studied: large, diurnal and relatively immobile on land Breeders territorial, but in non-breeding season they are highly gregarious Island BM BM BM BM Tide pool Rookery is a single row of territories held by Beach Master males California sea lion . .. Ocean BM BM BM Aggregations of females are irregularly spaced Male territories extend to water, access critical Landlocked BMs desert in < 1 d (overheating)
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4/12/2010 2 Zalophus breeding Difficult to define borders of male territories intruders are frequently tolerated, poor visual acuity Bulls defend May Augus Bulls defend May-August Reproductive activity highest from 15 June to 15 July Individual bulls maintain a territory for < 2 wks (average 9 d) Males do not become thin and emaciated Defecate on land, so must sneak off for a meal Zalophus male and female Zalophus os penis Harem is a misnomer for Zalophus Females come and go as they please Males make no attempt to corral females Males tend to follo female mo ements p and Zalophus breeding Males tend to follow female movements up and down beach or laterally Pregnant females land on beach 1 or 2 d before giving birth Estrus is postpartum in pinnipeds Most pups born in June Females in estrus usually solicit a nearby male
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Pinnipedia [Compatibility Mode] - 4/12/2010 32-35 species...

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