BIO 358 1st Edition Lecture 2 Outline of Last Lecture I Who are marine mammals II Anatomical Specializations III Physiological Specializations IV Human impact A Indirect B Direct V Current Events Outline of Current Lecture I Characteristics of Pinnipeds II Pinniped Breeding III IV V VI VII Human impacts on pinnipeds indirect direct Pinniped Distribution 3 families of pinnipeds A Family Otariidae i Characteristics ii Example species B Family Phocidae i Characteristics ii Example species C Family Odobenidae i Example specie D Fun words about scrotums Current Lecture Pinnipeds Order Carnivora pinnipeds fin footed carnivores Most are carnivorous All are fissipeds wich means Split footed Characteristics of all pinnipeds Large body size These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Fur or blubber insulation o Fur is only on fur seals Streamline body Modified appendages flippers Enhanced diving Enhanced thermoregulation Enhanced sensory systems for seeing hearing feeling in dark water Breeding Need hard substrate Access to land is required either continental fringes or islands Need to be able to move both in and out of water which makes them unique in the marine mammal world Human impacts on Pinnipeds Direct Impacts o Hunting for food fur and blubber oil o Hunted by fishermen because they are competitors for fish Indirect Impacts o Physical space beach houses o Death and injury due to fishing lines bycatch o Pollution debris toxins oil spills Distribution Cosmopolitan species are distributed world wide o No single species is cosmopolitan just the order as a whole Three Families of Pinnipeds Family Otariidae Otariids sea lions and fur seals Some Otariids exemplified by Steller s sea lion and Southern sea lions maintain polygynous mating system one male many females Extreme large body size in males enhances their ability to defend territories and females Galapagos Sea Lion o Walks on land o Walk on both for and hind limbs o Underwater movement flying motion to glide through water using pectoral flippers for thrust o Use lift base thrust forces entire stroke generates thrust California Sea Lion o External pinnae ears o They are the only species with visible ears Steller s sea lion Eumetopias jubatus o broad forhead and mane o heavily exploited o both endangered and threatened by the Marine Mammal Protection Act MMPA in multiple parts of its range o Population may not rebound Direct Threats kill by fishermen Indirect dead in fisheries equipment outcompeted by humans for fish Largest otariid species Males 3 m long and 1000 kg Females 2 m long and 270kg Sexual dimorphism o Highly aggressive Fur Seals Northern fur seal Callorhinus ursinus o Beautifully furred bear o smaller than sea lions with sharper noses o rely on fur for insulation even wet fur can insulate barely any blubber very dense fur o Discovered in mid 1700 s by Steller and Pribilof o Unregulated hunting for 100 years 250 000 individuals killed Near extinction 1911 North Pacific Fur Seal Convention first international wildlife conservation movement o o o Family Phocidae Phocids true seals 50 75 million individuals 90 of all pinnipeds Graceful and wind like lift based thrust in water Awkward on land No external ear pinnae Some Phociids Ringed Seal o Smallest seal o Polar bear s favorite dinner o Hide pups in ice lairs little cave of ice o Sucks that they taste so good Baikal seal o Only live in one lake o Lake in Baikal Siberia o Exclusively freshwater Hooded seal Cystophora cristata o Shortest lactation period of any mammal 4 days o 60 fat milk human milk is about 4 6 fat o pups gain 15 lbs per day o nose carries a bladder male nose looks like a clown nose bilobed nasa cavity allows male to evert his nasal septum and sac blood is pumped into it so it is bright read display for mating and fighting secondary sex characteristic o live on unstable ice fringes and floes Leopard Seal o Live in the Antarctic o High endothermic vertebrate predator they eat lots of things watch out yo Phocid pups and seals yumm Weddell Seal o Placid animal o Feeds on fishes o Great divers 300 meters for 70 minutes o Not afraid of humans Crab eater Seal o Doesn t eat crabs uh o Most abundant pinniped o Teeth form a sieve for catching krill o They are doing well They fell into a niche left open by humans when they hunted krill eating whales Southern Elephant Seal Mirounga leonine o Largest pinniped 5m long and up to 5 000 kg o Diving record 2 hours 1500 meters Northern Elephant Seal Mirounga agustirostris o Second largest pinniped o Deep diver large body size good deep diving o One of the best studied animals o Hunted to near extinction in the 18 00 s there were only 10 12 individuals left Now there are over 110 000 individuals Yay Hawaiin Monk Seal Monachus schauinslandi o Highly endangered 1000 individuals Due to tropical distribution o Solitary animals o Endemic to Hawaii o Sensitive to disturbances because of their low numbers o They are pretty tame Caribbean monk seals Monachus tropicalis o Discovered by Columbus in 1494 o Killed 100 per night for oil WHILE THEY WERE SLEEPING Jerks o Extinct in the 1950 s Family Odobenidae walruses odobenids Some Odobenids oh wait theres only one Walrus Odobenus rosmarus o Largest pinniped other than the elephant seal o o o o Uses tusks to pull up on ice Only extant species in the genus Only extant species with tusks Exploited for oil rough hide and ivory tusks Some New Terms Ascrotal No scrotum it never descends out of the body wall Scrotal Yes scrotum these species tend to be seasonal