© 2014 Pearson Education, Inc. Chapter 14 Lecture Animals of the Pelagic Environment

© 2014 Pearson Education, Inc. Pelagic animals use a variety of adaptations to help them survive. Marine mammals share similar characteristics with land mammals. Chapter 14 Overview

© 2014 Pearson Education, Inc. What Characteristics Do Marine Mammals Possess? 1.Land-dwelling ancestors 2.Warm-blooded - Homeothermic 3.Breathe air 4.Hair/fur during some stage of development 5.Bear live young 6.Mammary glands for milk

© 2014 Pearson Education, Inc. Examples of Major Marine Mammal Groups

© 2014 Pearson Education, Inc. Order Carnivora Prominent canine teeth Sea otters Polar bears Pinnipeds (feather foot) skin-covered flippers –Walruses –Seals –Sea lions –Fur seals

© 2014 Pearson Education, Inc. Order Carnivora Sea Otters –Inhabit kelp in coastal, eastern North Pacific –Extremely dense fur, lack insulating blubber –Hunted in 1800, made recovery –Eat many types of marine animals, use tools –High caloric needs –Small marine mammals

© 2014 Pearson Education, Inc. Order Carnivora Polar Bears –Massive webbed paws –Excellent swimmers –Thick fur, hollow hairs –Eat mostly seals

© 2014 Pearson Education, Inc. Order Carnivora Walruses –Large bodies –Adults of both genders have ivory tusks

© 2014 Pearson Education, Inc. Order Carnivora Seals –Also called earless seals or true seals –Differ from sea lions and fur seals

© 2014 Pearson Education, Inc. Seals vs. Sea Lions and Fur Seals Seals lack prominent ear flaps Seals have smaller front flippers Seals have fore flipper claws Seals have different hip structures and cannot move on land very well Different locomotion strategies

© 2014 Pearson Education, Inc. Order Sirenia Herbivores Manatees –Called Sea Cow –Coastal areas of tropical Atlantic Ocean Dugongs –Coastal areas of Indian and western Pacific Oceans

© 2014 Pearson Education, Inc. Order Cetacea Whales, dolphins, porpoises Elongated skull Blowholes on top of skull Few hairs Fluke – horizontal tail fin for vertical propulsion

© 2014 Pearson Education, Inc. Order Cetacea

© 2014 Pearson Education, Inc. Order Cetacea Adaptations to increase swimming speed –Streamlined bodies –Specialized skin structure 80% water Stiff inner layer Narrow canals with spongy material This skin structure allows there to a reduction in turbulence and drag

© 2014 Pearson Education, Inc. Order Cetacea There are three adaptations for deep diving 1.Use oxygen efficiently –Able to absorb 90% of oxygen inhaled –Able to store large quantities of oxygen Two times the amount of Red Blood Cells Nine times as much myoglobin as terrestrial animals Hemoglobin-oxygen storing pigment around Red blood cells –Able to reduce oxygen required for noncritical organs

© 2014 Pearson Education, Inc. Order Cetacea –Collapsible lungs –Alveoli – tiny chambers facilitate gas exchange with blood 2.Muscles insensitive to buildup of carbon dioxide –Muscles function during anaerobic respirtion

© 2014 Pearson Education, Inc. Order Cetacea 3.Ability to resist nitrogen narcosis. Physiologically affected by deep diving, but debilitating effects minimized Nitrogen narcosis – similar to drunkenness, occurs when diving too deep Decompression sickness – “the bends” –Nitrogen bubbles in blood from resurfacing too quickly –Bone damage, excruciating pain, possible death

© 2014 Pearson Education, Inc. Order Cetacea Suborder Odontoceti (toothed) –Dolphins, porpoises, killer whale, sperm whale –Echolocation to determine distance and direction to objects Determine shape, size of objects –One external nasal opening (blowhole)

© 2014 Pearson Education, Inc. Dolphins vs. Porpoises Porpoises –Smaller, more stout body shape –Blunt snout –Triangular, smaller dorsal fin –Blunt or flat teeth

© 2014 Pearson Education, Inc. Dolphins vs. Porpoises Dolphins –Larger, more streamlined shape –Longer rostrum –Falcate dorsal fin (hooked) –Pointy teeth like killer whales (orca)

© 2014 Pearson Education, Inc. Echolocation Good vision of marine mammals limited by ocean conditions. Dolphins and porpoises emit sounds from blowhole Sound passes through melon – organ on skull

© 2014 Pearson Education, Inc. Echolocation Toothed whales send sound through water. An evolved inner ear structure may help toothed whales pick up sounds. Whale forces air through nasal passage, click travels through spermaceti organ

© 2014 Pearson Education, Inc. Echolocation Sound is reflected, returned to the animal, and interpreted. Increased marine noise pollution may affect echolocation.

© 2014 Pearson Education, Inc. Intelligence in Toothed Whales Large brains relative to body size Communicate with each other Brains convoluted (shared by many highly developed organisms) Trainable Intelligence questioned

© 2014 Pearson Education, Inc. Order Cetacea Suborder Mysticeti Baleen whales Blue whale, finback whale, humpback whale, gray whale, right whale Vocalized sounds for various purposes Fibrous plates of baleen sieve prey items

© 2014 Pearson Education, Inc. Baleen Plates in whale mouths instead of teeth Whales fill mouths with water, baleen traps fish, krill, plankton

© 2014 Pearson Education, Inc. Baleen Rack of baleen from Gray Whale Individual slat of baleen Right Whale

© 2014 Pearson Education, Inc. Baleen Whale Families There are three Baleen Whale Families: 1.Right whales –Long, fine baleen, no dorsal fin –North Atlantic and North Pacific right whales most critically endangered whales in world 2.Gray whales –Short, coarse baleen, no dorsal fin, bottom feeder

© 2014 Pearson Education, Inc. Baleen Whale Families 3.Rorqual whales Short baleen Many vertical grooves Gulp large mouthfuls of water Two subfamilies: –Balaenopterids – Blue, Minke, Sei, Fin whales long, slender bodies –Megapterids – humpback whales robust bodies, long flippers

© 2014 Pearson Education, Inc. Humpback whales bubblenet feeding in Alaskan waters

© 2014 Pearson Education, Inc. 22,000 km (13,700 miles) annual migration from coastal Arctic Ocean to Baja California and Mexico Feeding grounds in Arctic (summer) Breeding and birthing grounds in tropical eastern Pacific (winter) Why Do Gray Whales Migrate?

© 2014 Pearson Education, Inc. Whales as Endangered Species Fewer whales now than before whaling International Whaling Treaty Hunting of gray whale banned in 1938 Gray removed from endangered list in 1993 as population rebounded

© 2014 Pearson Education, Inc. Whaling International Whaling Commission (IWC) 1948 – established to manage whale hunting In 1986, 72 IWC nations banned whaling Three ways to legally hunt whales: –Objection to IWC ban –Scientific whaling –Aboriginal subsistence whaling