Marine Mammal BehaviorMarine Mammal Foraging EcologyRole of Marine mammals in Marine ecosystemsSirenian DietPinniped DietOdontocete DietOtariid Foraging BehaviorPhocid Foraging BehaviorPinniped Health and Maintenance BehaviorsPinniped MatingPinniped Rearing BehaviorPinniped Migration and Social OrganizationMysticete DietOdontocete ForagingOdontocete Foraging ExamplesCetacean Mating PatternsCetacean Rearing PatternsMarine Mammal Behavior•Diet and Foraging Behavior•Health and Maintenance•MatingMarine Mammal Foraging Ecology•What an organism eats, where it eats and how much–Can be very difficult to determine in marine mammals•Some Methods to Analyze what wasn't digested, ie hard parts–Stomach contents •Can be hard to get–Feces•Easier to get •Serology: analysis of serums and enzymes–Certain enzymes will react with certain foods, thus telling you what the organism was eating•Fatty acids–Fatty acid composition of the prey influences the fatty acid composition of the predator.Role of Marine mammals in Marine ecosystems•Little is known–They do eat a lot though•Sperm whales eat >400million tons of squid/year•Antarctic–Our killing off of many whales the feed in the Antarctic has made more krill available for other animals–Consequently penguin and seal numbers have increased over the last 100 yrsSirenian Diet•Herbivores•Feed mostly on sea grass•In Shallow areasPinniped Diet•Not very specific–Fish, squid, crustaceans–Remember, they're like a dog•Strong preferences though–Often most of the food is <5 species of prey–Also strong seasonality to prey choice•Mostly eat fish and squid–Some eat krill, e.g. the crab eater sealOdontocete Diet•Odontocetes•Feed mostly on squid, fish and other large animals•Teeth designed for holding onto fast moving preyOtariid Foraging Behavior•Considered to be shallow divers with durations of 2-3 minutes–Feed mostly on fish in nearshore waters.–Tend to feed mostly at night or dawn, though the California sea lion dives only during the day–Otariid females forage during lactationPhocid Foraging Behavior•Phocids: Deep divers. –The deep divers are benthic (bottom) feeders.–Antarctic fur seal follows the krill. Dives are shallow at night because the krill are in the surface waters, but are deeper during the day, when the krill are deeper in the water column. –Phocid females, with a few exceptions, fast during lactation•After fasting, Northern Elephant seals will forage continuously 70 days for females and 120 days for males.•After molting return to sea for 241 days and females 296 days.Pinniped Health and Maintenance Behaviors•Seals have a problem with overheating, so they do things to keep cool.–During breeding females shift their position throughout the day so as to stay on cool, moist sand, or even move to tide pools. •Grooming–Necessary, but not social, meaning that they don’t groom each other. –Sea otters (not pinnipeds) groom constantly in order to maintain their thick fur coats and remove parasites.Pinniped Mating•The reproductive cycle is annual, synchronous and very stable.–There is a profound annual cycle in males of testicualr regression and recrudescence•The male's cycle is linked to the female's•Most pinnipeds are polygynous (one male for many females) –Five Tactics of Polygyny•Males defend resources used by females•Follow or defend females directly•Search for receptive females and move on to the next•Sequentially defend single females through mating•Aggregate and attract mates•The Northern Elephant Seal–Males have large harems, which are fought over by males in fierce battles. Consequently, the largest male tends to have the largest harem.Pinniped Rearing Behavior•Males tend to offer very little assistance in rearing the young•Three main strategies in maternal care–Foraging during lactation-Otariids and a few phocids, including the harbor seal•Females acquire a moderate store of blubber before coming ashore to give birth–Fasting during lactation-Phocids•Females build up large blubber reserves before nursing–Some combination of the two- Odobenids•Walrus calves travel with their mothers while feeding.Pinniped Migration and Social Organization•Many pinnipeds migrate during the year. –Coincides with seasonal breeding/foraging cycles.•Some, such as the harbor seal, have a definitive breeding ground from which they disperse, but don’t actually migrate. •Social organization is most complex during the breeding season. –Hierarchical dominance forms around harems, especially. –However, these rookeries don’t appear to have any real order to them, they are just places where many individuals congregate.Mysticete Diet•Very hard to determine diet–Fecal pellets are rarely available–Most stomach content data comes from commercial whaling or stranded animals–Can't pump their stomachs•Different Baleen Types•Those with coarse baleen feed on swarming zooplankton or fish–Blue whales, humpback whales•Benthic feeders filter out mud and invertebrates–Gray whales•Skimmers have log plates of baleen and feed on zooplankton such as copepods–Right whale, bowhead whaleOdontocete Foraging•Capture single prey, such as fish or squid•Those with fewer or no teeth tend to eat soft bodied prey.•Feed throughout the year and are therefore tied to regions with consistently abundant food.•Use echolocation to find food.Odontocete Foraging Examples•Sperm whales–Deep diving, squid eaters–Stay under for >1hr to depths >1000m–Tend to forage in groups•Orcas–Capture prey in large teeth at intermediate depths–Tend to feed on school fish and squid, but will also eat other marine mammals including large mysticetesAttack in pods•Small Odontocetes–Feed on fish, often in groups–Can also echolocate fish under the sand and dig for it. –"Fish Whacking" involves hitting a fish with the fluke and either stunning or killing it.–Strand feeding: dolphins will chase a school of fish up onto the shore and then jump after it.Cetacean Mating Patterns•A variety of precopulatory behaviors–Rubbing of bodies–Stroking pectoral fins–Rubbing Genitalia•Copulation–Bottolenose dolphins the pair orient in the same direction, the male mounting the female and intromission lasting only a few seconds•Humpbacked dolphins: male displays an erection and swims upside down beneath the female, repeating this over the course