Reading Comprehension

Read the passage carefully. Then answer the questions below.

For ages, sailors have said that it is good luck to see dolphins swimming alongside boats. Their presence meant that land was near, which would be vital information if a ship and her crew were in danger. Some dolphins have even protected shipwrecked sailors from sharks. It is no wonder that these unique and fascinating creatures have long been known as our friends.

You may think dolphins are fish, but they are actually mammals. They are related to whales and porpoises, and they evolved around 10 million years ago. Dolphins breathe air, give birth to live young and feed them milk. They are social animals, living together in groups called pods or schools that range in size of up to 12. In places rich in food, many schools can combine together to form pods of up to 1,000 dolphins.

Dolphins are thought to be intelligent animals because of their playfulness, curiosity, and quick learning ability. They seem to communicate with each other through a combination of squeaks, whistles, and clicks. While scientists don’t know what they are going on about, it is thought that dolphins are telling each other that food is nearby or warning each other of approaching danger. Dolphins use sonar to discover an object’s size, shape, and location. By sending out a series of clicks and receiving the echo that bounces off the object, they can differentiate between a shark and a boat.

Unfortunately, dolphins have faced increasing danger in recent years. Fishermen pursuing profitable tuna may accidentally trap dolphins in their nets, killing them in the process. These intelligent mammals of the sea deserve our protection and respect.