| They can measure from 1,5 to 3,5m and weight from 200 to 700 Kg. The better known dolphin is the bottle nosed dolphin (Tursiops trucatus) that measures like 2m. To eat the dolphins prefer to eat squids and fishes, they can get them even in deep water, under 1.000 meters. The sexual maturity is reached in the same time for females and males, normally when they get to the 2,5m of length. They depend of the oxygen to survive like us. With only one nostril on the top of their heads they can renovate 90% of the air in their bodies in each inhaling. That is a lot because in man the renovation in of 15%. Sleep As it’s breathing is under voluntary control. Dolphins take short catnaps, floating just below the surface, and then slowly rising to breathe. Often dolphins are very active during nighttime, for some this is their main feeding time. Gestation The period of gestation takes like 10 months and they have only one dolphin that is called a calf and at birth it is 90-130 cm long and it will grow up to 4 meters, living up to 40 years, when the calf comes out with a problem they expel it out before. Dolphins carry their young inside their womb and gestation is about 12 months for a bottlenose. The baby emerges tail first, and will suckle from its mother for up to 4 years (a calf may stop suckling sooner depending on circumstances). The baby will however stay with its mother for between 3-6 years, during which time it learns all about feeding techniques, social interaction and group foraging. Females are likely to stay within the family pod with their mother and sisters, though males will leave and form associations with other males. Tails Dolphins use their powerful tail flukes in an up and down motion to move through the water. They also use their tails when hunting, hitting a fleeing fish up into the air with their tail, stunning it, then scooping the fish up when it falls back into the water. A dolphin slapping its tail on the water in the wild may be a sign of annoyance, or a warning to other dolphins of danger. Ears . Dolphin's ears are barely noticeable marked only by a small hole just behind the eye. In a bottlenose dolphin the ear is about 5-6 cms behind the eye and only 2-3 mm in diameter. Blood They are warm blooded like us. Instead of the major blood supply to the brain running up the outside of the neck, as in land animals, it passes through an artery within the fused vertebrae. This insures a constant supply of blood when the dolphin dives to extreme depths in the ocean. Teeth and mouth They have 120 teeth. A dolphin's teeth aren't used for chewing -- it swallows food whole -- but they do help it grab prey. Some scientists also think the teeth are spaced in such a way to help the dolphin analyse sound waves that bounce back to it from an object. Their teeth are interlocking rows of conical pegs, suitable for holding slippery fish. They eat their fish whole, head first. In the wild an open mouth is a sign of aggression, as is head nodding. A sign of greater aggression is violent jaw clapping. Melon This is the fatty, rounded section of a dolphin's forehead, and it's critical to its extremely sensitive and complex use of echolocation. The melon acts as an acoustical lens to focus sound waves into a beam that is projected in front of the animal. o Melon and corresponds to our upper lip. Dorsal fin a dolphin's dorsal fin is cartilage that can be as distinctive as a human's face and is used by scientists to identify individuals. Dolphins that have dorsal fins -- not all do -- seem to use them for stability Eyes Dolphins come equipped with elastic lenses on their eyes that expand and contract to let them focus both above and below the water. And they have special glands that protect their eyes from salt water Skin Like human skin, dolphin skin has many nerve endings, which explains why tame dolphins like to be stroked. Dolphin skin is also extremely delicate and easily injured by rough surfaces. It can be cut by a sharp fingernail, but tends to heal quickly Blowhole The blowhole serves as a dolphin's nostrils, allowing it to breathe while swimming at top speed. To breathe while asleep, female dolphins lie on the water's surface with their blowholes exposed to the air; males sleep just below the surface and rise to breathe periodically as a reflex action. When the stale air, warmed from the lungs, is exhaled it condenses and vaporises as it meets the cold air outside. This is rather like when you breathe out on a cold day and a small cloud of warm air appears. This is called the 'blow', or 'spout', and each cetacean's blow is different in terms of shape, angle and height. This is a how experienced whaler or whale-watchers can identify cetaceans at a distance. |
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