IA'S ALL ABOUT THE CUTE ANIMAL- DOLPHIN!!!

Dolphins are marine mammals, but there is also a fish species that's often called "dolphin" or "dolphin fish". Its scientific name is Coryphaena hippurus. To avoid confusion with the mammal species its Spanish name "dorado" or its Hawaiian name "mahi mahi" is often used.

Because of the confusion between the mammal and the fish species dolphins have in the past erroneously been called porpoises, especially in some US regions, where the fish species is common. In older books you can encounter the name "bottlenose porpoise" for the bottlenose dolphin, for instance. Dolphins and porpoises are however members of different whale families.

Dolphins have to be conscious to breath (Williams et al, 1990). This means that they cannot go into a full deep sleep, because then they would suffocate. Dolphins have "solved" that by letting one half of their brain sleep at a time. This has been determined by doing EEG studies on dolphins. Dolphins sleep about 8 hours a day in this fashion. Recent research confirmed that dolphins have only one eye closed when sleeping. The state (open or closed) of one eye remains constant for on average an hour, after which it switches state (Goley, 1999). REM (Rapid Eye Movement) sleep, usually associated with dreaming has been recorded only very rarely. Some scientists claim dolphins do not have REM sleep at all.

A dolphin's behavior when sleeping/resting depends on the circumstances and possibly on individual preferences. They can either:

• swim slowly and surface every now and then for a breath

• rest at the surface with their blowhole exposed

• rest on the bottom (in shallow water) and rise to the surface every now and then to breath.

Dolphins communicate mainly by means of sounds. These sounds include whistles, but also so-called pulsed sounds, which are often described as squawks, barks, rasps, etc. But they also use breaching (jumping and falling back into the water with a loud splash) and pectoral fin (or flipper) and tail (or fluke) slaps (hitting the flipper or fluke on the water surface). Body posturing and jaw popping also have a role in communication. This list is not exhaustive.

As for language, we do not know if they have one. Several studies have demonstrated that dolphins can understand a structured language like ours. This same has been demonstrated for a number of other animals species as well (gorilla, bonobo, California sea lion, parrot). Some studies also indicate that dolphin vocalizations are complex enough to support some form of language. However, to date it has not been demonstrated yet that they indeed use a language for communication among themselves.

i LOVE DOLPHINS!!!