Dolphins
Written by Anne Brophy Chetwynd
Dolphins are mammals and are related to whales and porpoises in a group of mammals fully adapted to aquatic life.
They frequently leap above the water, which is called porpoising. When travelling, jumping can save the dolphin energy as there is less friction while in the air. Other reasons dolphins leap out of the water include orientation, social displays, non-verbal communication, and pure entertainment.
Researchers agree that dolphins are social creatures and seem to depend on this interaction while hunting, mating and defending themselves and their pods. Dolphins sometimes show empathic behavior and establish strong social bonds, such as trying to save weakened fellow dolphins or whales. They have also been seen protecting human swimmers from sharks by swimming circles around the swimmers or charging the sharks to make them go away.
Dolphins produce a variety of vocalizations, usually in the form of clicks and whistles. They also use nonverbal communication by touch and posturing. Clicks and whistles help them stay together while they travel.
Dolphins have two flippers on the underside toward the head: a dorsal fin and a tail fin. They swim by moving their tail fin and rear body vertically, while their flippers are mainly used for steering.
Dolphins are able to hear frequencies that are least 10 times what the best human hearing can offer. Their hearing is adapted for air and water and is so well developed that some can survive even when blind. Dolphins have no sense of smell and are not thought to have a good sense of taste.
Bottlenose dolphins living in high seas feed on several species of fish and squids, while dolphins near the coasts consume fish and invertebrates found in coastal areas. Dolphins can also be seen following fishing boats to consume the discarded fish or take captive fish from the nets.
The bottlenose dolphins that live in South Carolina are unique among dolphins on the East Coast: they engage in what is called ‘strand feeding’. This is a method of feeding that occurs within hours of low tide in the marshes and creeks, and involves several dolphins rushing up onto the mudflats, pushing a wall of water in front of them. Fish are also carried along, and when both hit the mud, the dolphins grab the stranded fish.
This is a risky technique, as the further up the bank the dolphins land, the harder it is to slide or wriggle back into the water. Enjoy a dolphin cruise while you visit the island. It’s a magical experience you won’t forget.
Sources: www.dolphins-world.com; Town of Hilton Head; American Cetacean Society: http://acsonline.org/fact-sheets/bottlenose-dolphin/
