Dorsal fin of an Orca

A dorsal fin is a fin located on the backs of some fishes, whales, dolphins, and porpoises, as well as the (extinct) ichthyosaurs. The Orca or Killer Whale ( Orcinus orca) less commonly Blackfish or Seawolf, is the largest species of the Oceanic dolphin family fin is a surface used to produce lift and Thrust or to steer while traveling in Water, air or other Fluid media Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Whales are marine mammals which are neither Dolphins (ie members of the families Delphinidae or Platanistoidae) nor Porpoises Orcas Dolphins are Marine mammals that are closely related to Whales and Porpoises There are almost forty species of dolphin in seventeen genera. Porpoises are Small Cetaceans of the Family Phocoenidae; they are related to Whales and Dolphins They are distinct from dolphins Ichthyosaurs ( Greek for 'fish lizard' - ιχθυς / ichthyos meaning 'fish' and σαυρος / sauros meaning 'lizard' were giant Its main purpose is to stabilize the animal against rolling and assist in sudden turns. Some animals have developed dorsal fins with protective functions, such as spines or venom. Many catfish can lock the leading ray of the dorsal fin in an extended position to discourage predation or to wedge themselves into a crevice. Catfish ( order Siluriformes) are a very diverse group of bony Fish.

Dorsal fins come in a variety of shapes and sizes.

They are infamous for being the sign of an approaching shark. Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body

Whales, dolphins, and porpoises

In relation to the size of the creature, the dorsal fin of the male orca is quite large, as much as 1. The Orca or Killer Whale ( Orcinus orca) less commonly Blackfish or Seawolf, is the largest species of the Oceanic dolphin family 8 m high. (The female orca has a shorter dorsal fin that is more curved. ) Many (30-100%) captive male killer whales (orcas) experience collapse of the dorsal fin, possibly because lack of exercise through turning leads to diminished muscle tone, other possible factors include change in diet, sex drive and pressure in the pool due to counter-clockwise swimming, this reacts with the sodium nitrate in the whale's pituitary gland and leads to the loss of connective tissue in the dorsal area (Only about 1% of wild orcas have collapsed dorsal fins. Muscle (from Latin musculus, diminutive of mus "mouse" is contractile tissue of the body and is derived from the The pituitary gland, or hypophysis, is an Endocrine gland about the size of a Pea. ) The dorsal fins of most other whales are relatively small. The bowhead whale has no dorsal fin at all, as an evolutionary adaptation to its life spent cruising under icepack. The Bowhead Whale ( Balaena mysticetus) also known as Greenland Right Whale or Arctic Whale, is a Baleen whale of the right whale family eVolution is the third Album by eLDee, it was due to be released in 2008 The dorsal fins of whales develop distinctive nicks and wear patterns with time, and this fact is used by wildlife biologists to identify individuals in the field. A wildlife biologist' is someone who studies wild animals and their habitats