Penguins are lovely animals. Most people like them. But now as many as 10 of the 17 kinds of penguins are in danger of disappearing. The number of penguins has decreased by ( ) 30% since 1987. Penguins are black and white birds that live in the southern part of the world. They are common in the Antarctic Continent   ,New Zealand, Australia and South America. Many live near cold waters  . But some live near warm waters in Galapagos Islands. Penguins  cannot fly, but  they are fine swimmers. The shape of their body helps them to survive. Penguins eat fish and krill   . They have short wings that help them to dive up to 900 feet to catch larger fish. They can swim 10-15 kilometers an hour which lets them protect themselves. They also have lots of body oil that helps in keeping them dry in the water. The warming of the earth is the reason for the decrease in the number of penguins. The hotter and hotter air has caused ocean waters to become warmer. Higher water temperature has decreased the fish and krill. Some years later these birds are completely unable toreproduce. And many adult penguins die of hunger. Too much fishing, exploration for oil and oil leaks   also make penguins be in danger. Poisonous things in ocean waters are another danger. Penguins also have their enemies, including sharks, seals and sea lions. What's the passage mainly about?
Fish and krill have decreased. Ocean waters are polluted. Sharks and seals are the enemies of penguins. The decrease in the number of penguins.