Dolphins are marine mammals that are directly related to whales and porpoises. They are often considered as one of the most intelligent animals on the Earth, which makes them popular as performing animals at aquariums. They are social creatures and roam about in pods of about a dozen individuals, though pods might join temporarily to form a super pod in areas of extreme abundance of food. Dolphins are adept at producing a wide range of sounds using nasal air sacs located just below the air hole. Dolphins communicate with each other by making whistle-like sounds, which are created by vibrating connective tissue.
The sounds produced by dolphins for echolocation purposes are one of the loudest produced by any mammal. Dolphins frequently jump above the water surface for different reasons, which makes them easy to spot and popular with tourists. Primary reasons for this behaviour include conservation of energy, positioning, social exhibition, fighting and non-verbal interaction. Dolphins can be found worldwide, generally in the shallow seas of continental shelves. They are carnivores and usually consume fish and squid. Here is a list of well-known dolphins which can be spotted at major dive sites around the world:
With a snout featuring a permanent 'smile' owing to its curved mouth, Bottlenose dolphins are instantly recognisable as the intelligent and fascinating stars of many aquarium shows. Being highly intelligent mammals, they can be trained to perform complex tricks. Bottlenose dolphins surface two to three times a minute to breathe, making them easy to spot. Interacting and communicating with other dolphins through an intricate system of whistles and squeaks, these dolphins locate prey with the aid of echolocation and often travel and hunt in groups.
Often seen following fishing boats in the hope of receiving leftover food, the Bottlenose dolphin is found in tropical oceans and warm waters around the globe. Diving sites where these dolphins can be spotted include the Isles of Mull, Iona, Coll and Tiree in Scotland, Dubai in the UAE and Providenciales in Turks and Caicos.
The Commerson’s dolphin possesses very distinctive markings, with a black head, dorsal fluke and fin and a white throat and body. They are often mistaken for porpoises due to the close physical resemblance, but are undoubtedly of the dolphin family as evidenced by their bold outgoing behaviour.
These dolphins have a broad spectrum of foods as a part of their diet, and consume a variety of sea life such as fish, squid, octopus and other invertebrates. The Commerson’s dolphin can be found in shallower waters along South America’s southernmost tip, and in other naturally sheltered harbours or ports. Two main locations where they can be sighted are the inlets of Argentina and the Strait of Magellan close to the Falkland Islands.
The Striped dolphin is easily recognised by the stripe that runs from its dark coloured rostrum, around the eye, and down along the side to the rear flank. The underside is usually considerably lighter in colour – either white or pink. Found in large groups of anywhere from several hundred to several thousand, these dolphins are very active in the water. Quite acrobatic, they can be seen doing flips, spins and leaps out of the water upside down.
Striped dolphins are often found in warm waters, usually staying in tropical and subtropical regions. They can be found in both the Atlantic and Pacific Ocean, usually offshore, though sometimes in deeper waters closer to shore. Diving spots conducive to sighting the Striped dolphin include the Faroe Islands, southern Greenland and Molokini, Kee beach and Hanauma Bay in the waters of Hawaii.
Killer Whales (Orcas)
Orcas, or killer whales as they are more famously known, are in reality a part of the dolphin family. They are the biggest of all the dolphin species and one of the most powerful and intelligent predators on Earth. Possessing sharp teeth as long as ten centimetres, their diet comprises mainly of large marine wildlife like seals, sea lions and even whales. Killer whales have very distinctive markings of jet black and brilliant white and grey. Their underbelly is white in colour, with a large white patch on the side of the head and a grey saddle patch.
The adult male Orca features a large dorsal fin which can grow up to 1.8 metres long, making them easily distinguishable from females. They are extremely intelligent animals and are inquisitive and approachable as a result. Despite what their name suggests, Killer whales do not harm humans in the wild and violence within a group is rare. They are among the broadest ranging mammals on Earth, and prefer cold coastal waters although they can be found in both the polar regions and as well as the Equator. They are occasionally sighted at diving spots like the Isles of Coll and Sound of Harris in Scotland, Tutukaka in New Zealand and Playas del Coco in Costa Rica.
The Risso dolphin is easily identified at close range owing to its extremely scarred body and square head. Sturdy flat-headed animals lacking distinctive beaks, they possess long pointed flippers and a tall dorsal fin. Its diet is comprised of mostly squid and other invertebrates. Though they usually do not approach boats, Risso dolphins can sometimes be spotted surfing bow waves.
They are a widely spread species and live in deep waters of outer continental shelves, and also in regions ranging from the tropics to the temperate regions in both the hemispheres. They can be spotted at Orkney in northern Scotland, Gulf of Alaska and Estancia Tunel, Isla Redonda and Islas Bridges (all in the Beagle Channel).
The pilot whale is one of the largest oceanic dolphins, and is beaten in size only by the Killer whale. Their bodies are long, with swollen heads and a protruding melon. Though pilot whales assemble in big numbers offshore, their pod sizes usually vary from ten to sixty individuals. Frequently spotted inshore, they sometimes become stranded by severe storms.
The pilot whale is a highly interactive dolphin and makes a number of sounds that can be described as squealing, whistling, loud smacking, whining and also snoring. They can be found in oceans worldwide and at famous diving locations like the North Taicos and Grand Turk at Turks and Caicos, Tutukaka in New Zealand, Cat Island, San Salvador Bimini and Eleuthera in the Bahamas, and Carriacou at Grenada.