Nature Description:
Dolphins are marine mammals that are closely related to whales and porpoises. Dolphins are among the most intelligent animals and their often friendly appearance and seemingly playful attitude have made them popular in human culture. Most dolphins have acute eyesight, both in and out of the water, and they can hear frequencies ten times or more above the upper limit of adult human hearing. Though they have a small ear opening on each side of their head, it is believed that hearing underwater is also if not exclusively done with the law, which conducts sound to the middle ear via a fat-filled cavity in the lower jaw bone. It is believed that dolphin teeth are arranged work as an antenna to receive incoming sound and to pinpoint the exact location of an object.
Comparing species relative intelligence is complicated by differences in sensory apparatus, response modes, and nature of cognition. Dolphins are social, living in pods of up to a dozen individuals. In places with a high abundance of food, pods can merge temporarily, forming a superpod; such groupings may exceed 1,000 dolphins. Individuals communicate using a variety of clicks, whistles and other vocalizations. They make ultrasonic sounds for echolocation.
Dolphins also display culture, something long believed to be unique to humans. In May 2005, a discovery in Australia found Indo-Pcific Bottlenose Dolphin teaching their young to use tools. They cover their snouts with sponges to protect them while foraging. This knowledge is mostly transferred by mothers to daughters, unlike
simian primates, where knowledge is generally passed on to both sexes. Using sponges as mouth protection is a learned behavior. Another learned behavior was discovered among river dolphins in Brazil, where some male dolphins use weeds and sticks as part of a sexual display.
