Marine Mammals An Introduction

Classification of a Mammal Phylum Chordata Class Vertebrata Order Mammalia

What is a Mammal? Breathe air using lungs Endothermic Skin has hair Maintain a steady internal temp regardless of environment Skin has hair Some only have hair as young Brain is larger in relation to body size and far more complex

Whale with hair

What is a Mammal? Bear live young Viviparous, with a few exceptions The embryo receives nutrients and oxygen through the placenta The newborn is fed by milk produced by the mother’s mammary glands Produce few (but well cared for) young

What will we be talking about? Order Cetecea Suborder Mysticetes – Baleen whales Suborder Odontocetes – Toothed whales Dolphins, orcas, pilot whales, belugas, porpoises Order Pinnipedia Sea lions, seals, fur seals, and walrus Order Carnivora Sea otters and polar bears Order Sirenia Manatees and dugongs

Evolution of Whales/Dolphins Whales arose around 55-65 million years ago (mya) from now extinct ancient land mammals that ventured into the sea Today’s cetaceans have vestigial hind limbs Fossils indicate the earliest baleen whales appeared 30 mya Most modern forms of both baleen and toothed whales appear in the fossil record 5-7 mya

Evolution of Pinnipeds The earliest sea lions and fur seals appear in the fossil record about 12 mya The earliest seals appear about 12-15 mya Ancestor fossils show that seals were once able to walk on land The earliest walruses appear about 14 mya

Evolution of Sirenians Fossil record in incomplete Relationship between manatees and their ancestors is not known Some evidence points to ancestral sirenians dating back to 45-50 mya Protein analysis shows that closest modern relatives are elephants and aardvarks

Evolution of Sea Otters Fossil record shows the presence of freshwater otters dating back to 5-23 mya They descended from fish-eating, otter-like ancestors about 5-7 mya

Evolution of Polar Bears The oldest polar bear fossil is only 130,000 years old Scientists believe they diverged about 200,000 years ago from an ancestral brown bear Fun fact: Polar bears and brown bears are so closely related that they can breed and produce fertile offspring Scientists believe evolution is taking a turn and causing convergence of these two species, not divergence

Grolar Bear

Conservation Efforts US Marine Mammal Protection Act of 1972 (MMPA) Made it illegal to hunt or harass any marine mammal in US waters Objective: maintain the health and stability of the marine ecosystem and to obtain and maintain an optimum sustainable population of marine mammals Does have provisions for the following: Allowing indigenous people to continue their traditions Collecting animals for research and education

Conservation Efforts The Endangered Species Act (ESA) of 1973 Protects any species that are listed as endangered or threatened Threatened means close to be endangered Endangered means species is on the brink of extinction Species are added and removed from the list often as their numbers increase or decrease

Conservation Efforts Marine Debris Cleanup Program Developed by the Marine Mammal Research Program Established to decrease the amount of marine debris in the water and on the coast

Conservation Efforts IUCN/The World Conservation Union Only worldwide conservation organization Encourages a worldwide approach to conservation Categorizes threatened species as endangered, vulnerable, and rare Also established a Species Survival Commission to work with zoological parks and aquariums to maintain worldwide biological diversity

Conservation Efforts Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) International treaty developed in 1973 to regulate trade in certain wildlife species Established worldwide controls over trade for threatened and endangered species

Conservation Efforts International Whaling Commission (IWC) Signed by 14 countries to regulate whaling Purpose: manage whale stocks and protect their future Monitors whale populations Makes recommendations on how many whales indigenous peoples can harvest in subsistence hunting Problems: Only signed by 14 countries No way to enforce the regulations