Marine Birds & Pinnipeds Chapter 8
PENGUINS • This class includes all birds. Birds have an outer covering of feathers, are endothermic (warm-blooded), have front limbs modified into wings, and lay eggs
Most scientists recognize 17 species of penguins: • Emperor, king, Adélie, gentoo, chinstrap, rockhopper, macaroni, royal, Fiordland crested, erect-crested, Island , yellow-eyed, fairy (also known as little blue), •Magellanic, Humboldt, African (formerly known as black-footed), Galápagos, • Some scientists recognize an 18th species: the white-flippered form of fairy penguin, Eudyptula albosignata
Fast Facts • The average life expectancy of penguins is probably 15 to 20 years. Some individuals live considerably longer • High mortality occurs among the young • When in the water, penguins may be eaten by leopard seals, fur seals, sea lions, sharks, or killer whales • In some places, such as islands in the southern Indian Ocean, fishermen still use penguin meat for bait
The origin of the word "penguin" • The origin of the word "penguin" has been a subject of debate. The theories of researchers and historians range from references to the amount of fat (penguigo in Spanish and pinguis in Latin) penguins possess to the claim that the word was derived from two Welsh words meaning "white head". The most agreed-upon explanation is that "penguin" was used as a name for the now-extinct great auk, which the modern-day penguin resembles and for which it was mistaken
DDT • Traces of dichlorodiphenyltrichloroethane (DDT) and other pesticides (chlorinated hydrocarbons) have been found in the tissues of Adélie and chinstrap penguins. Scientists speculate that these pollutants were transported by ocean currents or other animals. Their appearance in antarctic penguins is significant in that these toxic substances have now reached the pristine Antarctic
Adaptations • As in most birds, penguin hearing is probably good, but not as acute as that of marine mammals • A penguin's eyes are adapted to see clearly both in air and under water • Penguins have color vision and are sensitive to violet, blue, and green wavelengths of light
CALIFORNIA SEA LION • ORDER - PINNIPEDIA • Pinnipeds are seals, sea lions, and walruses. Some scientists classify pinnipeds as a suborder of the order Carnivora. • FAMILY - OTARIIDAE • Otariids, also referred to as "eared seals", include all sea lions and fur seals. Otariids are characterized by having external ear pinnae (ear flaps) and long flippers. • GENUS, SPECIES - ZALOPHUS CALIFORNIANUS
Habitat • California sea lions inhabit rocky and sandy beaches of coastal islands and mainland shorelines. They may frequent sandbars; sheltered coves; tide pools; and structures such as piers, jetties, and buoys.
Migration • During the nonbreeding months, most males migrate north from breeding grounds. Southern California males migrate to Puget Sound, Washington and British Columbia; males from Baja California migrate to the Channel Islands. • Most females either stay within their breeding grounds or move south during nonbreeding months.
Physical Characteristics • Male California sea lions reach about 2 to 2.5 m (6.5–8 ft.) and 200 to 400 kg (440–880 lb.). At maturity male California sea lions are much larger than females. • Female California sea lions reach about 1.5 to 2 m (5–6.5 ft.) and 50 to 110 kg (110–240 lb.).
CALIFORNIA SEA LION • The foreflippers have all the major skeletal elements of the forelimbs of land mammals, but they are modified for swimming. The "arm" bones are shortened, and the flippers are lengthened by cartilaginous extensions at the tips of the finger bones.
CALIFORNIA SEA LION • Like land mammals, sea lions have five digits in the hind limbs. They are lengthened by cartilaginous extensions.
Senses cont. • Underwater vision is acute. Like other pinnipeds, California sea lions have rounded lenses that allow their eyes to focus on light that is refracted upon entering water • On land, California sea lions have good discrimination of bold outlines and rapid movements. Humans approaching too quickly will cause an alarm reaction • Recent studies show that sea lions can discriminate color in the blue-green spectrum; this is probably an adaptation for their aquatic environment
Senses • Hearing is one of the most important senses for a California sea lion • Researchers believe that under water, a California sea lion can hear sounds in the range of 1 to 40 kHz, with a peak sensitivity of 15 to 30 kHz. California sea lions generally vocalize between 1 to 4 kHz. The average hearing range for humans is about 0.02 to 20 kHz. • Hearing in water is probably acute, with good directional ability. • In air, a California sea lion's hearing is probably slightly inferior to that of a human
Adaptations • California sea lions usually stay submerged three minutes or less; however, they can remain submerged for as long as 10 minutes • California sea lions, like marine mammals, have a slower heart rate while diving. A sea lion's heart rate can slow from about 95 to about 20 beats per minute • The muscle of California sea lions has a high content of the oxygen-binding protein myoglobin to help prevent muscle oxygen deficiency • A sea lion often regulates its body temperature by lifting and exposing one or more flippers. The blood vessels just under the skin dilate and absorb or release heat to the environment.
Communication / longevity • Sea lions have vocal cords • A California sea lion's primary means of communication is vocalization. Sea lions produce sounds both above and below water • Sea lions communicate visually, with postural displays • California sea lions probably live an average of 15 to 25 years. California sea lions in zoological habitats have been known to live 30 or more years.
Walrus • The common name, walrus, originated with the Danish word hvalros, meaning "sea horse" or "sea cow". The Russian word for walrus is morzh. Arctic natives call the walrus aivik (Inuit) or aivuk (Yu'pik). • Male Pacific walruses weigh about 800 to 1,700 kg (1,764-3,748 lb.) and are about 2.7 to 3.6 m (9-12 ft.) long.
Walrus • Ears, located just behind the eyes, are small inconspicuous openings with no external ear flaps • Walruses live to a maximum of about 16 to 40 years. (Nowak, 1999)
Walrus communication • Walruses have vocal cords • Walruses are among the most vocal of the pinnipeds. They produce growls, taps, knocks, grunts, barks, soft whistles, rasps, and clicks. • Walruses produce sounds both above and below water
Manatees • Class – Mammalia • Order – Sirenia • The living sirenians consist of three species of manatees and one species of dugong • The Greek name for this order is derived from the sirens of Greek mythology. Sirens were sea nymphs who lured sailors to their island with their mesmerizing songs • Closest modern relative: elephants
Communication • Manatees emit sounds under water. The chirps, whistles, or squeaks are probably produced in the larynx. They seem to make these sounds when they are frightened, sexually aroused, or interacting with each other. • Vocalizations are an integral part of the cow-calf relationship. Cows respond to squeals of their calves from more than 61 m (200 ft.) away • The hearing capacities of manatees are not well studied, but it is known that manatees are adapted for hearing low frequency sounds • Manatees have large ear bones that are well developed at birth. Some scientists have suggested, however, that the main area of sound reception is not the small ear openings but rather an area near the cheekbones. A manatee's cheekbones are large and relatively oily, and they are in direct contact with the ear bones
Longevity • Manatees probably live a maximum of about 50 to 60 years • A consequence of manatee tooth replacement is that scientists cannot use the teeth to age individual manatees, a procedure commonly used for many other species of marine mammals. Scientists instead use a method of aging manatees based on studying growth patterns that develop on ear bones • In early 1996, about 150 manatees died in southwest Florida. Scientists determined the mass mortality was caused by a red tide • Manatees are very susceptible to cold weather
Trouble for the manatees • Due to their dark color and because they are slow swimmers, manatees are difficult to see in the water. At least 20% to 22% of manatee deaths in Florida occur from watercraft accidents yearly. Collisions with boats and barges is the largest human-related factor causing manatee deaths in Florida • Although the engine propellers are dangerous, collisions with boats cause the most watercraft related deaths. In 1995, 12 manatees expired from propeller injuries while 25 died from impact wounds. Collisions with boats cause life-threatening internal injuries that are often hard to locate and treat
This manatee's flipper became entangled in a crab trap and will require medical treatment.
Manatees’ troubles • Flood gates and navigation locks • Poaching and vandalism • Accidental entanglement and pollution • Habitat destruction • The human population in Florida increases by nearly 1,000 people daily • About 250,000 acres of forests are lost every year in Florida and roughly one-fourth of the state remains semi-natural
Conservation • All four species of sirenians are endangered or threatened • The Florida manatee is one of the most endangered marine mammals in the United States • All species of sirenians are protected to some extent by national or local acts in every country they inhabit
MARINE ZOOLOGICAL PARKS • Marine zoological parks such as SeaWorld Florida and SeaWorld California help conserve manatees. SeaWorld is authorized to rescue and rehabilitate ill, injured, or orphaned manatees
Having manatees at marine zoological parks provide the opportunity for the public to learn about these rare animals