Hobbies And Interests
Bottlenose Dolphins
The most famous member of the Delphinidae family, the bottlenose dolphin, is also one of the most common. Gaining notoriety for their aquatic show acrobatics and silver-screen appearance as "Flipper," these remarkably intelligent animals can be found in oceans worldwide. Though, they prefer temperate waters averaging a surface temperature of 50 to 90 degrees Fahrenheit.
Scientists classify bottlenose dolphins into two ecotypes (two forms): coastal and offshore. Dolphins living in shallower, warmer water tend to have smaller bodies with larger flippers, allowing more maneuverability and more rapid heat-loss to cool their bodies. Offshore bottlenose dolphins live in deeper, colder parts of the ocean, and possess larger bodies to temper heat loss and a blood composition more suitable for diving to great depths. Similar distinctions exist in other delphinids.
Killer Whales
Also known as orcas, killer whales also gained notoriety by starring in aquatic shows and in movies like "Free Willy." They aren't the only whales in the Delphinidae family, but they take the crown for most well documented. As with bottlenose dolphins, this offers researchers an opportunity to generate a general understanding of the habitat preferences of other delphinids. Killer whales inhabit every ocean on the planet, making them the most widely distributed mammal on earth after humans. Scientists find orcas in an astonishing array of habitats from the Antarctic to the tropics, and even miles up freshwater river systems. However, they seem to prefer coastal waters to the deep ocean.
Though occurring worldwide, the largest killer whale populations stick to Arctic and Subarctic waters, as do most delphinid whales.
River Dolphins
A lesser known group of delphinids, the river dolphins, is also one of the most endangered and most unique. Varieties of these dolphins peruse the murky waters of the Amazon River, the Yangtze River in China and several river systems in South Asia, including the Indus River in Pakistan. Much research still needs to be done on these interesting animals, but it seems they compensate for the low visibility nature of their habitat with echo location and by using their long beaks to sift the murk for river fish.
Porpoises
Though the terms dolphin and porpoise often get used interchangeably, true porpoises actually belong to a different taxonomic family entirely. The family Phocoenidae consists of only six species, and members lack the prominent beak of the delphinids. Dorsal fins on porpoises tend to be small or nonexistent. However, like delphinids, phocoenids inhabit waters all over the world. The common porpoise, or harbor porpoise, resides in temperate to subarctic bodies of water where the surface temperature stays below 60 degrees Fahrenheit. They range in waters along North Pacific, North Atlantic and Black Sea shores feeding on a variety of seafood. Harbor porpoises usually eat 10 percent of their body weight each day.