The History of Dolphins

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In the animal kingdom there are many different groups or "classes" such as reptiles, birds, amphibians and mammals. All mammals have five characteristics in common:

warm-blooded
breath air
give birth to live young
born with hair
nurse their young

Dolphins are one of many marine mammals that inhabit the sea, others being manatees, otters, sea lions and whales.

All the whales, dolphins and porpoises belong to the order called Cetacea, which can be further divided into three smaller groups known as suborders. The Archeocetes were the ancient whales and are now extinct. The second group, the Mysticetes, include, among others, the gigantic blue, grey and humpback whales. Members of this suborder have two blowholes and instead of teeth, have a series of comb-like plates called baleen which they use to strain plankton and shrimp from the water as a food source.

The largest suborder is the Odontocetes , also known as the toothed whales which includes groups such as the sperm whales, belugas and dolphins. The number of teeth may vary with the species, but all use their teeth for catching, not chewing, their food. There are ten different families of toothed whales.

Though many people often confuse the two, dolphins and porpoises are different families of toothed whales. Divided into six different species, porpoises are generally smaller than dolphins, darker in color, and found in deeper and cooler waters. Porpoises usually lack the rostrum or "bottlenose" that most dolphins have. Another distinct trait of porpoises is their teeth: they have flat, spade-shaped teeth versus the conical-shaped teeth of dolphins.

Finally, there are about thirty species of dolphins found in our oceans, a few being the white-sided, spotted and bottlenose. It is the Atlantic bottlenose dolphin, Tursiops truncatus, that is most well known to people.

These animals tend to live in the shallow waters in which people frequently choose to swim and boat. This species of dolphin also does very well under human care and are usually your marine park performers.

Atlantic Bottlenose Dolphins
The Atlantic bottlenose dolphin can be found throughout the temperate, tropical and sub-tropical waters of the Atlantic Ocean. With a great deal of variety in size, appearance and behaviors, these dolphins are further divided into approximately nine different sub-species. For example, the bottlenose dolphins off the United Kingdom may weigh up to 1200 pounds and migrate short distances to locate food or evade predators. In the shallow Bahamian waters, Atlantic bottlenose dolphins grow up to nine feet in length weighing up to 500 pounds. Average lifespan for this species in the wild is approximately 30 years.

Research confirms that these animals currently live equally as long under human care and, in many cases, live longer, healthier lives than their counterparts in the wild. In marine parks and aquariums, dolphins are protected from the dangers of pollution, predators, and events such as El Nino, which triggered food shortages for many marine mammals in the late 1990’s. The oldest dolphin under human care lived to be 48 years of age. Due to public display, advances in animal care and medicine have greatly contributed to the improved health of cetaceans under human care, as well as to the successful rehabilitation and release of stranded, injured animals.

In general dolphins are well known for their bottlenose or rostrum with the built-in smile. The rostrum is a bony extension of their skull used to touch and move objects since they don’t have hands. The hair on a dolphin’s upper rostrum - a "mustache" of sorts - falls out either just before the animal is born or shortly thereafter.

Inside the mouth, 88 to 120 conically-shaped teeth can be found. Remember, dolphins do not chew their food. The teeth are used to grasp prey before swallowing it whole. The stomach of a dolphin is highly acidic, capable of digesting whole foods. As far as diet, these dolphins are known as "catholic" feeders, eating whatever fish species is locally available. Primarily they eat schooling fish - herring, mackerel, mullet or capelin to name a few - but also some crustaceans and molluscs, such as squid or shrimp.

Vocalizations
The blowhole on top of the dolphin’s head is their nose. Dolphins can remain submerged up to 8 minutes but generally take a breath about every 30 seconds. In fact the blowhole is the only place they breathe. The blowhole, not the mouth, is also the only place from which sounds come. Beneath the opening of the blowhole are three pairs of nasal air sacs and by squeezing air from one sac to another, dolphins produce sounds. Vocalizations are broken down into three main types: buzzes, clicks and whistles.

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