Wildlife workers in Florida are feeding manatees to keep them from starving. 【小题1】 So far, the rescue workers have already given out 25 tons of lettuce.

Manatees are huge sea mammals that can be as long as 4 meters when grown.【小题2】 In spite of their size, manatees only eat plants that live in the sea. That’s one reason they’re sometimes called “sea cows”. They spend most of their time in warm shallow water looking for food.

But Florida’s manatees have been on the US government’s list of endangered animals since 1967. Most threats to manatees come from humans. One of the biggest problems facing the creatures are boats. 【小题3】 Manatees are curious and fairly slow, which has led to thousands of manatees being injured or killed.

【小题4】At one point, there were only about 2, 000 manatees left in Florida. But by 2016, there were roughly 8,800 manatees.

But now manatees are facing a new challenge: they can't get enough to eat. Many of the beds of sea grass that manatees depend upon have been killed by human-caused pollution. Sea grass began to disappear around 2011. Warming seas, combined with polluted water and fertilizers that have washed off of farmlands, have created huge growths of algae on the ocean’s surface.

Last year, 1,101 manatees died from starving.【小题5】 Many of the manatees that remain are so thin that their ribs can be seen. Often they have trouble swimming.

So last December, wildlife experts came up with a plan to get emergency food to the manatees. They decided to feed them green vegetables like lettuce and cabbage. Long term, Florida is working to help restore sea grass beds. But that will take time.