Dolphines

Prereading activity

1. Is a dolphin a fish?

2. How old can dolphins be?

3. How fast can dolphins swim?

4. Do dolphins chew?

Reading :-

Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in seventeen genera. They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating fish and squid. 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 done with the lower jaw, which conducts sound to the middle ear via a fat-filled cavity in the lower jaw bone. The dolphin's sense of touch is also well-developed, with free nerve endings densely packed in the skin, especially around the snout, pectoral fins and genital area. However, dolphins lack an olfactory nerve and lobes and thus are believed to have no sense of smell, they do have a sense of taste and show preferences for certain kinds of fish. Since dolphins spend most of their time below the surface, tasting the water could function like smelling, in that substances in the water can signal the presence of objects that are not in the dolphin’s mouth

Dolphins occasionally leap above the water surface, performing acrobatic figures. Scientists are not certain about the purpose(s) of the acrobatics. Possibilities include locating schools of fish by looking at above-water signs like feeding birds, communicating with other dolphins, dislodging parasites or simple amusement.

Play is an important part of dolphin culture. Dolphins play with seaweed and play-fight with other dolphins. At times they harass other local...