Dolphins are aquatic mammals, which belong to the whale family. The bottlenose dolphin in particular is very easy to research because of their adaptability to captivity. The bottlenose dolphin, tursiops truncates, is black or slate blue above and lighter underneath. It has dark flippers and is usually 6-12 feet in length. (Encyclopedia Americana 262). It can travel at speeds of up to 25 miles per hour. (Cox 107). .
Communication .
Dolphins are believed to imitate human speech by means of echolocation. (Encyclopedia Americana 262). Echolocation is emittance of sounds in the form of short pulses, called clicks, and listening for return echoes. (Carwardine 131). The process of echolocation is believed to work like this: Sound is produced internally. The "brain" focuses this sound into a beam. Reflected echoes carrying information about targets are received at the "acoustic window" area of the dolphins" lower jaw. The sound is then transmitted by the fatty organ in the lower jaw to the middle ear and then to the brain for processing and interpretation. (Carwardine 133).
In spotted dolphins, each one is believed to have its own identification signal, or a "signature whistle." (Cox 123) Echolocation is a highly sophisticated sense requiring much processing of information. Each echo only lasts between ten and one hundred milliseconds. (Donoghue and Wheeler 30). Not only are sound signals used to catch food and navigate, it is also used to communicate sexual interest. Females indicate their enthusiasm during sexual intercourse by giving out signals to indicate identity and show emotion. (Donoghue and Wheeler 37).
Behavior and Leadership .
Dolphins exhibit aggressive and submissive behavior through their roles of leadership. Within groups of dolphins, there is a tendency toward dominance hierarchies. The largest males tend to top the ranking, followed by the smaller males, females, and juveniles.
