Dolphins... Rescuers and healers

Did you enjoy your swim into the dolphin world last week? Well, if you did, we will provide you with more fascinating information about these beautiful mammals who seem to have a close relationship with humans.

Today we feature more information about their social and eating habits, reproduction,therapeutic effects on humans, how they help animals and humans in distress and details of different species, which includes the Killer Whales or Orcas, the largest in the family of dolphins.

Remember the movie titled Free Willy and Michael Jackson's beautiful song 'Will you be there?' which features a massive killer whale? Well, can you believe that this huge mammal is a member of the dolphin family which consisits of many other creatures reffered to as the Pygmy Killer Whale, False Killer Whale, Black Dotted Whale and the Atlantic Humpback Whale? Dolphins found in Hawaii are generally termed as porpoises by the fishermen.

There are many who confuse dolphins with a marine species known as dolphin fish which are also called dorado or mahi mahi. There are around 335 species of marine dolphins and four species of river dolphins, namely Amazon - Botto, Franciscana, Indus and Ganges and Yangtze River Dolphin.

Dolphins to the rescue!

Stories of dolphins helping not only other injured dolphins and stranded whales, but also humans, date from the days of the ancient Greeks.

One such interesting legend involves Arion, the musician at the court of the King of Corinth. Legend has it that Arion travelled to Sicily to enter a singing contest. As he was very talented, Arion won the singing contest and won a small fortune as prize money.

However, on his return journey home, the sailors on board decided to kill him and keep the treasure for themselves, so they threw Arion into the sea. But a school of dolphins who had been attracted to that area by his beautiful singing, had carried him on their backs, safely to Corinth.

This may be just a legend, but even in today's real world there are many stories of how these gentle creatures have come to the rescue of humans.

There are stories of dolphins helping a team of humans who were trying to rescue a pod of pilot whales stranded on New Zealand's Tokerau Beach in 1983. Then, there is a report on how a British diver who was swimming with some friends and dolphins in the Red Sea came under attack by a shark when he got separated from his friends. The dolphins had saved his life by forming a protective circle around him and keeping the shark at bay until rescue arrived.

Have you heard or read such heart-warming stories about these marine mammals? Don't you think it's sad that despite all they do to help humans, that some humans kill them?

Dolphin healing

One of the first centres to investigate the therapeutic effect swimming with dolphins has on humans, especially on children with speech and other disabilities, is the Dolphin Research Centre in Florida.

Dolphin-human therapy, pioneered by American Psychologist Dr. David Nathanson is practised in many centres worldwide today.

Social habits

Dolphins are social creatures that live in pods which are also known as schools. Usually, these pods number around a dozen or more individuals, but, when pods get together temporarily for food purposes, these numbers could exceed a thousand.

They form strong bonds with each other and are often seen swimming together, playing, leaping, doing acrobatics, and enjoying riding the waves together. Dolphin friends may be spotted swimming face to face.

It has been observed that these highly intelligent creatures believed to have evolved 10 million years ago are also very helpful in times of trouble. For instance, when an injured or ill dolphin is facing the threat of drowning, the other dolphins help by supporting the drowning dolphin with their bodies and enabling it to keep the blowhole through which it breathes, above water, for it to breathe easily.

Dolphins breathe through this blowhole located at the top of their heads, and so it is important to prevent water from entering it. As the dolphin could drown if water gets into it, the blowhole does not open when the dolphin is in the water. It opens only when the dolphin comes to the surface.

Now, how does this happen, you may wonder. Complex nerve endings around the hole helps the dolphin to sense pressure changes and temperature changes that normally take place when it nears the surface.

Once it reaches the surface, it could release air through its blowhole at speeds of 100 mph. Apart from helping their own kind, these highly intelligent animals help other species in danger, including humans.

Eating habits and reproduction

Dolphins are carnivores and feed mostly on fish, squids and other small sea creatures. They hunt food using their sonar systems and are active during the night. They are predators and chase their prey at high speed using a number of methods of hunting such as herding, stunning, foraging and mudding.

Babies - Dolphin babies or calves are born tail first, with their eyes open. Their senses are very alert and they have enough muscular co-ordination to follow their mother soon after they are born.

Bottlenose dolphin calves are about 90-130 cm when they are born, but grow up to about 4 mtrs as adults.

The calves stay with their mother for up to 3 or 6 years, nursed by them for at least four years. During their stay with their mother, the calves learn everything about feeding techniques, social interaction and group foraging.

Of the many species of dolphins found swimming in the tepid waters of Hawaii, the most common are the Spinner Dolphins, Spotted (Kiko), Bottlenose and Rough-toothed Dolphins. The Hawaiian Spotted Dolphins are shaped and coloured differently to other spotted dolphins.

In general, Spinners are slender with long, thin beaks and distinct stripes, connecting the long pointed flippers to the eyes. They weigh around 45 kg to 75 kg and are 1.3m to 2.1m in length. They too eat squid and fish like other dolphins, but they eat mostly at night.

Spinners are found in tropical and sub-tropical oceans worldwide. They often mingle with Pilot Whales, Spotted Dolphins and Skipperjack Tuna.

Dusky Dolphins are relatively small and are called the 'acrobats of the sea' because they leap right out of the water.

Usually, these dolphins are found in temperate waters. The Stenos or Rough-toothed Dolphins are thought to be uncommon. They have white lips, sharp teeth, large pectoral fins and tall dorsal fins. There are numerous fine ridges on their teeth.

The Indo-Pacific Humpbacked Dolphin has a crooked dorsal fin which is wide at the base, rising to a triangle pointed tip.

The dorsal fin surmounts a hump which is more prominent in the humpbacks found in the Indian Ocean.

In the Common Dolphins, the flanks are coloured ochre and grey and the dolphins have a distinct stripe around the eye.

The dorsal fins are triangular shaped and prominent. The flippers are pointed, while the bodies are slender and streamlined. They too sometimes leap out of the water like the Dusky Dolphins.

The spotted dolphins have characteristic white-tipped noses. It's a small, toothed whale that has a long, beak-like snout, a sickle-shaped dorsal fin and sharp teeth. The Bottlenose Dolphins have stream-lined bodies and rounded heads with a distinctive beak.

They are the largest among the beaked dolphins. They have a tall, sickle-shaped dorsal fin and broad, slightly pointed flippers. Bottlenose Dolphins are not endangered. They are occasionally killed for their meat by accident or because they often swim with tuna and get trapped in nets. These dolphins are among those used to perform at marine shows. The TV series Flipper portrayed a Bottlenose dolphin.

The Killer Whale or Orca is a very fast swimmer, and an efficient predator that eats fish, squid and other small marine creatures. They even attack huge young blue whales.

It is sometimes called the 'Wolf of the sea.' They have 10-13 pairs of large, interlocking fonical, enamelled teeth on both the upper and lower jaws. The teeth curve inwards and backwards.