What Are The Characteristics Of Dolphins?

With a perpetual smile on their faces, dolphins, as members of the carnivorous cetacean family that also includes whales and porpoises, use echolocation – a type of sonar – to see while they swim beneath the waves. In December 2015, biologists and researchers in the US and UK captured an image of a submerged researcher using only the echolocation beam from a dolphin. The image clearly details the shape of the man and even depicts the fingers on his hand.

Dolphins range in color from light gray to dark gray on their backs, which lightens to white on their underbellies and beneath their jaws. Dolphins generally range in size from 6 feet to over 12 feet and can weigh as much as 600 pounds. Smaller dolphins typically live in rivers and along the coasts, while the larger dolphins range far out to sea. The geographical location and the water's warmth contributes to the dolphin's size, as colder waters make for bigger dolphins. A dolphin's powerful fluke tail, moving up and down in the water propels the mammal forward. Pectoral fins on each side of the body help them steer while swimming, but these are also used like hands to touch or stroke other dolphins. The dorsal fin atop the dolphin's back helps mammal expel heat.

Dolphins form strong bonds with other dolphins, and if one dolphin become injured, the others help it to reach the surface. Most dolphins stay in groups of up to 12 dolphins, but many groups often come together in the ocean wild, at which time, dolphins may exit one group and join another. Like the water they live in, dolphin prefer fluid social groups. When in large groups, they hunt and forage together, with some dolphins taking turns to hunt or stand guard. Like humans, dolphins give live birth and nurse their young. Dolphin babies – calves – nurse for up to 18 months and stay with the mother for up to three years. A nanny dolphin, male or female, often accompanies the mother and the baby as it grows. The nanny or auntie dolphin is the only one the mother allows near the calf.

Although the dolphin's playful side is what makes it a big attraction in captivity, Sea World reports that this behavior also has an important purpose for dolphins in the wild. Dolphins often chase one another and throw objects, such as seaweed from one to the other. These natural behaviors allow the dolphin to practice its hunting skills. Play is also a way for dolphins to bond with one another.

Researchers at University of St. Andrews in Scotland discovered that bottlenose dolphins use special communication techniques in the wild when meeting new pods. Each dolphin has its own signature whistle, which scientists consider as their individual names. Dolphins can recognize other dolphins in the wild they haven't seen in a long time by their signature whistles, something other creatures don't do – label or name. Studies done in Hawaii, detail the memory, cognition and the understanding of abstract words. For example, a researcher told a dolphin to swim "through" another researcher standing in the water, using a form of sign language, and the dolphin, did as instructed, swimming between or through the researcher's legs.