Hobbies And Interests
Mammals
The killer whale is a mammal that can grow to around 31 feet long and is recognizable by its black and white coloring. The males are bigger than the females, even though killer whale pods are matriarchal -- they're led by the eldest female, who may be the grandmother or mother of the other whales. The males also have a tall dorsal fin that's straighter than the female's, which is a little curved. Killer whales live in the upper layer of cooler seas, from the Atlantic pack ice down to the West Indies. Killer whales are intelligent and voracious hunters that will prey on other whales, seals and fish.
Fish
One of the many oceanic fish species is the yellowfin tuna. This fish grows to about 6 feet long and can weigh up to 450 pounds. It's dark blue above and the fins and finlets, small fins that grow in rows along the dorsal and anal sections of the animal, are yellowish with dark edges. The yellowfin usually lives in open seas in the mid depths or near the surface, which makes it easy to find. They usually live in the Atlantic from Massachusetts to Brazil and in the Pacific from California to Chile. The yellowfin is a very valuable and sought after fish, by both commercial and sports fishermen. It travels in schools and eats crustaceans, squid and other, smaller fish.
Cnidaria
Many cnidaria have jelly like bodies and form colonies. Pyrosomas are colonies of animals related to salp, small (1 to 10 cm long) organisms that swim by pumping in water and ejecting it. The pyrosoma acts like a tunnel made of jelly with an open end. The colony also moves by sucking water through the tube and forcing it out the open end. The creature is bioluminescent and lights up brightly when it's touched, even forming patterns of light along its length. It can be up to 4 feet long. The pyrosoma can usually be found in the upper levels of warm waters.
Mollusks
Many mollusk species live in the ocean. The Pacific giant octopus is a calm and intelligent creature. It's solitary and spends much of its life in or near its den. It can grow to weigh over 440 pounds and have a radius of close to 32 feet. Its eyesight is excellent and it's the only invertebrate who hunts by sight; its usual prey are crustaceans and squid. After it captures its prey, it drags it back to the den. When the octopus is finished, it deposits bits of shell or bone outside the den, which eventually forms middens, or large shell heaps. Despite its size and intelligence, the giant octopus only lives for about four years.