Whales and dolphins living in the Indian Ocean by Sri Lanka
The Blue whale is a marine mammal and the largest animal ever known to have existed. The lenght of blue whales is usually around 25 meters and their weight between 150-170 metric tons. The flippers are 3–4 metres long. Blue whales can reach speeds of 50 kilometres per hour over short bursts, usually when interacting with other whales, but 20 kilometres per hour is a more typical traveling speed. When feeding, they slow down to 5 kilometres per hour. Blue whales most commonly live alone or with one other individual. It is not known how long traveling pairs stay together. In locations where there is a high concentration of food, as many as 50 blue whales have been seen scattered over a small area. However, they do not form the large, close-knit groups seen in other baleen species.
Maximum lenght: 30 meters, maximum weight: 180 metric tons
The Sperm Whale is the largest species of toothed whale, with adult bulls (males) growing to be about 15–18 metres long, and weighing about 45–70 tonnes. Sperm whale hast the biggest brain of any animal.
The Fin whale is the second longest whale and the sixth largest living animal after the blue whale. The American naturalist Roy Chapman Andrews called the fin whale "the greyhound of the sea" because of its great speed when chased and slender build.
maximum lenght: 27 meters
|Both common dolphin species are medium metres long, sized dolphins. Adults range between 1.9 and 2.5 metres and can weigh between 80 and 235 kilograms although a range between 80 and 150 kilograms is more common. Males are generally longer and heavier. The color pattern on the body is unusual. The back is dark and the belly is white, while on each side is an houglass pattern colored light grey, yellow or gold in front and dirty grey in back. They have long, thin rostrums with up to 50–60 small, sharp, interlocking teeth on each side of each jaw.|
|They are grey, varying from dark grey at the top near the dorsal fin to very light grey and almost white at the underside. This countershading makes it hard to see, both from above and below, when swimming. Adults range in length between 2 and 4 metres. and in weight between 150 and 650 kilograms. Males are on average slightly longer and considerably heavier than females. In most parts of the world, the adult's length is about 2.5 meters (8.2 ft), with weight ranges between 200 and 300 kilograms. Their size varies considerably with habitat. Bottlenose dolphins can live for more than 40 years but average lifespan is 20 years or less.|
|Risso's have a relatively large anterior body and dorsal fin, while the posterior tapers to a relatively narrow tail. The bulbous head has a vertical crease in front. Infants are dorsally gray to brown and ventrally cream-colored, with a white anchor-shaped area between the pectorals and around the mouth. In older calves, the non-white areas darken to nearly black, and then lighten (except for the always dark dorsal fin.) Linear scars mostly from social interaction eventually cover the bulk of the body. Older individuals appear mostly white. Most individuals have 2-7 pairs of teeth, all in the lower jaw. Length is typically 3.0 malthough specimens may reach 4.3 m. Like most dolphins, males are typically slightly larger than females. This species weighs 300–500 kilograms making it the largest species called "dolphin".|
|The Spinner Dolphin is usually dark gray, with darker patches in the tail stock, back and throat. Usually it has a creamy-white patch on the belly, though this varies considerably. Their beaks are distinctively long and thin, with a dark tip. The fins, also, are lengthy for dolphins of this size.
Adults vary in length from 129–235 centimetres (51–93 in) and weight from 23–78 kilograms (51–170 lb). Gestation requires about 10 months. Females reach maturity at four to seven years. Males require seven to ten years. Their longevity is unknown. Group sizes vary from just a few animals up to thousands. They often ride boats' bow-waves.
|Colouring of striped dolphins is very different and makes them relatively easy to notice at sea. The underside is blue, white or pink. There are one or two black bands that circle the eyes, and then run across the back, to the flipper. These bands widen to the width of the flipper which are the same size. There are two further black stripes running from behind the ear - one is short and ends just above the flipper. The other is longer and thickens along the flanks until it curves down under the belly just prior to the tail stock. Above these stripes the dolphin's flanks are coloured light blue or grey. All appendages are black as well. At birth, individuals weigh about 10kg and are up to a meter long. By adulthood they have grown to 2.4 m (females) or 2.6 m (males) and weigh 150 kg (female) or 160 kg (male). Longevity is about 55–60 years.|
Source and more info on www.wikipedia.org