DOLPHINS By 5 th Grade Biome Dolphins live

DOLPHINS By (5 th Grade)

Biome • Dolphins live in the Aquatic Biome. • This biome can be broken down into two basic regions: • • Freshwater and Marine The bottlenose dolphin is found worldwide in tropical and temperate marine ocean waters. The largest of all the ecosystems, oceans are very large bodies of water that dominate the Earth’s surface.

Biome • Bottlenose Dolphins live in the pelagic zone of • the ocean, which includes those waters further from the land, basically the open ocean. The pelagic zone is generally cold.

Biome • The flora in the pelagic zone • include surface seaweeds. The fauna include many species of fish and some mammals, such as whales and dolphins. Many feed on the abundant plankton.

Habitat • Bottlenose dolphins are found from northern • Japan and California to Australia and Chile and in worldwide oceans. Bottlenose Dolphins can be found in harbors, bays, lagoons, gulfs, and estuaries.

Food Chain • Tiger, Bull and Dusky • • Sharks are the main predators. They also get caught in fishermen’s nets as they fish for tuna. Dolphins are hunters and they mainly eat fish and squid. They hunt near the surface of the water.

• Dolphins are not fish; • • • they are considered mammals. They breathe air directly into their lungs. They are warm-blooded. They give birth to live young. They are like small whales, and can swim more than 25 miles per hour. They have 94 teeth and they travel in groups called pods. Interesting Facts

Bottlenose Dolphin Behavior • They are known for their playful • • behavior. They can jump 20 feet. When hunting they chase fish toward shallow water. They corral schools of fish and take turns swimming into the school to feed. Watch this video.

Bottlenose Dolphin Behavior

Structure and Function • Stream-lined bodies and a rounded head with a distinctive beak. • They have a tall, falcate (sickle-shaped) dorsal fin and broad, slightly pointed flippers. • Use their tail flukes • Melon is fatty and helps direct sound. when hunting, by hitting a fish up into the air with their tail, stunning it, then scooping the fish up when it falls back into the water.

Communication • Dolphins use snaps and whistles to warn other dolphins of predators.

Adaptations to Survive • Bottlenose dolphins have a • • layer of blubber under their skin to keep warm. During a deep dive (up to 1000 feet) their lungs and ribs partially collapse. They store oxygen in their blood and muscles instead of their lungs.

Evolution • Inside their pectoral fins, dolphins have a skeletal structure similar to a human arm and hand. • They have a humerus with a ball and socket joint. • They have a radius and ulna, as well as a complete hand structure, including five finger bones. • This makes scientists think dolphins evolved from a terrestrial ancestor.

Evolution Diagram of a dolphin dorsal fin bone structure and a human arm and hand bone structure.

Life Cycle • Bottlenose dolphins breed in early March • • to mid May. Baby dolphins grow to an adult dolphin and then reproduce. Dolphins can live up to twenty five years in the wild.

Reproduction • When dolphins mate, they • • • don't really get married. They just swim belly to belly for about 30 seconds. The average time a calf grows inside a mother is about 10 -12 months. Calves have to be born tail first otherwise they will probably drown before they are able to fully come out of their mother.

Reproduction • After the two dolphins mate and have their baby, they part, and the mother dolphin takes care of the baby by herself.

Babies • When they are born, dolphins have whiskers on their rostrum. • A dolphin’s whiskers are about one quarter inch long, and will fall out after birth, because of water pressure. • Babies stay with their mom 3 -6 years.

Human Impact • Bottlenose dolphins have been • caught for meat, leather, oil, and meal (for fertilizer and animal feed). Are affected by pollution, heavy boat traffic, habitat destruction, and competition for schools of fish by fisheries. • Caught accidentally in fishing nets. Recent conservation efforts have greatly reduced the number of dolphin deaths. But scientists believe that actual deaths may be more than reported.

References Photos used with permission and retrieved from: http: //www. pics 4 learning. com Video used with permission and retrieved from: http: //www. nationalgeographic. com/kids/creature_feature/0108 /dolphins 2. html Facts: http: //www. dolphins. org/Learn/lmm-phys. htm http: //www. enchantedlearning. com/subjects/whales/ species/Bottledolphin. shtml http: //www. aqua. org/downloads/pdf/Dolphins. pdf Kovacs, Deborah. All About Dolphins! Bridgeport, Connecticut: Third Story Books, 1994. Gay, Tanner Ottley. Whales and Dolphins in Action. New York: Aladdin Books, 1991.