Marine Turtles, Mammals and Seabirds Chapter 9 Marine Turtles, Mammals and Seabirds

Marine Reptiles Four types of marine reptiles exist today: Sea Turtles Sea Snakes Marine Iguana Saltwater Crocodile

Sea Turtles All species of sea turtles are threatened or endangered Endangered = a species is under direct threat of species survival (extinction is a definite threat) Threatened = the species may become endangered Both designations give these species protection under the Endangered Species Act

Sea Turtles Seven or eight species of sea turtles exist today: Leatherback sea turtle Loggerhead sea turtle Hawksbill sea turtle

Sea Turtles Seven or eight species of sea turtles exist today: Olive ridley sea turtle Kemps ridley sea turtle Australian flatback sea turtle Green sea turtle

Sea Turtles Structurally, sea turtles have an upper shell known as the carapace and a lower shell known as the plastron. The ribs are expanded in size and fused to their shell All sea turtles have powerful jaws, but no teeth

Sea Turtles Like other reptiles, sea turtles are poikilothermic and ectothermic although the leatherback sea turtle is so large that its body temperature is normally several degrees above the ambient water temperature

Sea Turtles Females normally breed every 2-4 years These females must return to land to deposit their eggs near the dune line (above the high tide) Females dig a hole in the sand using only the back flippers During their breeding year, females may lay up to 7 clutches of eggs Each clutch of eggs normally has an average of 120 eggs, although large variations in these numbers have been recorded Leatherback Hatching

Sea Snakes There are 55 species of sea snakes These snakes are found only in the Indian and Pacific Ocean These snakes have a laterally flattened body with a paddle-like tail for propulsion through the water Most species are 3-4 feet in length as adults Banded Sea Krait Laticauda colubrina

Sea Snakes Sea snakes breed at sea and most species are ovoviviparous A few species still return to land to lay eggs Bites from sea snakes can be fatal for humans– the sea snakes are related to the cobra and have powerful venom Fortunately, sea snakes are not known to be aggressive Sea snakes are carnivorous and mainly feed on fish Olive sea snake (Aipysurus laevis)

Marine Iguanas Marine iguanas live on the Galapagos Islands While they are called marine, they only spend a portion of their time in the water They dive to feed on seagrass near the shore A large portion of their day is spent basking on the shore to warm up from their dives in the cold water surrounding the Galapagos marine iguana Amblyrhynchus cristatus

Seabirds Seabirds are endotherms: able to maintain a constant body temperature derived through metabolic means The feathers that cover the body are coated with an oil from glandular secretions This oil helps to waterproof the body The hard shelled egg provides more protection than the leathery shell of reptiles

Seabirds Many species of seabirds are colonial nesters - they nest in large colonies of individuals near the shore some on cliffs, others in low shrubs or trees, others directly on the ground Some species are monogamous and mate for life Atlantic Yellow-nosed Albatross Thalassarche chlororhynchos Atlantic Yellow-nosed Albatross

Marine Mammals Characteristics of Mammals: Skin possesses hair Homeotherms (endotherms) Mostly viviparous with placenta Mammary and other glands Larger brain in relation to body size Many sexually dimorphic (males and females look different in size, coloration, features, etc)

Major Groups of Marine Mammals Pinnipedia – seals, sea lions and walrus Carnivora – sea otter and polar bear Sirenia – dugong and manatees Cetacea – whales, dolphins and porpoises

Order Pinnipedia Below is a comparison of sea lions/fur seals versus true seals. Notice the external ear of sea lions/fur seals (not present in seals). Also notice that sea lions/fur seals can rotate the rear limbs forward for more efficient locomotion on land.

Order Pinnipedia Seals: 19 species Most live in cool or cold water Monk seals are the exception – they live in warmer waters Hawaiian and Mediterranean monk seals are endangered Caribbean monk seals have not been seen since the 1950’s Hawaiian Monk Seal Monachus schauinslandi Mediterranian Monk Seal Monachus monachus Caribbean Monk Seal Monachus tropicalis

Below is a illustration of a walrus.

Order Carnivora Characteristics of Sea Otters fine, dense fur coats Their forefeet are small and dexterous with retractile claws flipper-like hind feet are broad and webbed Consume sea urchins, crabs, abalone, clams, mussels, octopus, and fishes.

Order Carnivora Characteristics of Polar Bears: Polar bears are the largest land carnivore Thick fur coat that appears white in coloration, but is really translucent. Black skin color is readily apparent on the nose, eyes, lips and footpads. Diet includes seals, walruses, narwhals, beluga whales, whale carcasses, fish, reindeer, birds, eggs, berries and kelp Polar bears hunt for seals

Order Sirenia Characteristics of Manatees: Manatees are primarily herbivores All living manatee species are found in warm tropical and subtropical waters. Both fresh and marine manatees Amazonian Manatee Trichechus inunguisd Manatees

Order Cetacea Characteristics of Cetacea: This order includes whales, dolphins and porpoises Fore limbs are modified into flippers Fin-like tail is known as a fluke. Nostrils are located on the top of the head as a single or double opening known as a blowhole.

Order Cetacea Two suborders: Baleen Whales (Mysticetes): Two blowholes Filter feeders: small fish and invertebrates

Examples of Baleen Whales

Whales may be identified from their fluke shape, blow pattern or side view during a dive (as shown below).

Order Cetacea Two suborders: 2. Toothed whales (Odontocetes): Single blowhole Single pegged-like teeth The teeth of dolphins are conical and interlocking, while those of porpoises are spade-shaped Toothed whales include dolphins, porpoises, belugas, narwhals, sperm whales, killer whales, river dolphins, and beaked whales.

Examples of Toothed Whales

Adaptations for Diving: Rapid breathing prior to dive -known as apneustic breathing Lungs remove 90% of O2 from air (as opposed to 20% for humans) Marine mammals have more blood than non-diving mammals (means more hemoglobin to carry oxygen) Muscles employ anaerobic respiration as necessary (results in lactic acid build-up)

Echolocation Sound waves are emitted as a series of clicks of varying frequencies Melon directs the outgoing sound waves After the echo strikes an object, it is reflected back These reflected echoes are received back by the melon and lower jaw The longer it takes a echo to return, the farther away the object is located

Marine Mammal Behaviors Marine mammals as well known for their vocalizations such as the “barking” of sea lions and songs of the humpback whale. Marine mammals engage in play activities regularly including sexual play.

Marine Mammal Behaviors Many species of marine mammals are known to jump out of the water and crash back into the water on their backs. This is known as breaching. The reasons for this behavior may be removing parasites, a warning signal, to avoid suitors or to have fun!

Marine Mammal Behaviors Marine mammals sometimes hold their bodies out of the water. This behavior is known as “spyhopping.”

Migration Many marine mammals are known for their long migrations. The longest migration is that of the gray whale; this migration is over 11,000 miles!!

Marine Mammal Behaviors Care giving and Strandings: When one member of a group (pod) of animals is sick/injured, other members will care for it. Mass strandings are often the result of caregivers following a sick/injured animal to shore. As an example, 58 pilot whales mass stranded in July, 2002 at Chapin Beach. Volunteers desperately tried to protect the animals from the summer heat with sheets and water, but unfortunately the elements proved too extreme for the whales. Cetacea