Iceberg the huge piece of ice

A huge chunk of ice floating in the ocean is called an iceberg. Many icebergs look as large as 10-story buildings. Most of their size, however, is hidden underwater. Icebergs can easily damage or destroy passing ships.Icebergs come from glaciers, or large masses of slowly moving ice. Because glaciers are made of frozen snow, icebergs contain freshwater, not salt water. In a process called calving, pieces of a glacier break off into the ocean. The pieces, or icebergs, move slowly through the ocean. They can drift for thous&s of miles. When they reach waters that are warm enough, they melt away. About 10,000 to 15,000 icebergs form each year in the Arctic. More than 10 times that number form in Antarctica. Only a few hundred icebergs reach shipping routes each year.Small icebergs, called growlers, are about the size of a gr& piano. Average icebergs are the size of houses or large buildings. The largest icebergs ever seen were miles across & hundreds of feet high. Only about one eighth of an iceberg is visible above the water. The part above water may look like a mountain, a slab, or a dome. It is usually white but can also have dark layers of dirt. Although icebergs are extremely heavy, they float for the same reason that an ice cube floats in a glass of water: ice is less dense, or lighter, than water.Any ship that hits an iceberg at moderate speed can be damaged. The most famous iceberg in history sank the Titanic, a ship traveling in the northern Atlantic Ocean, on April 15, 1912. The ship's side scraped the iceberg, which tore holes in the hull. Within three hours the ship was at the bottom of the ocean.After the loss of the Titanic, several nations worked together to establish the International Ice Patrol. The patrol warned ships about icebergs floating in Atlantic shipping routes. Today the U.S. Coast Guard runs the patrol. It uses radar & other technology to locate icebergs.Hyenas are most active at night. They live alone or in packs. The spotted hyena is the most social species, forming packs of 80 or more animals. Within these groups spotted hyenas communicate with each other with a variety of signals & sounds. Among them is the famous “laughing” call.During the day spotted hyenas are often seen st&ing around a group of feeding lions. This has led many people to believe that hyenas merely wait to steal some of the lions' kill. It is true that hyenas feed on the carcasses, or dead bodies, of animals such as zebras & gazelles after lions are done with them. In many cases, however, the hyenas actually hunted & killed the prey the night before. Often their calls draw lions to the kill. The hyenas are then forced to wait at a safe distance for the larger animals to finish feeding.Hyenas may breed in any season of the year. About 90 to 110 days after mating, the female gives birth to a litter of one to six cubs. Unlike dogs, hyenas are born with open eyes. The young, called cubs, may stay with their mother for more than a year. Young female spotted hyenas usually join their mother's group, while young males w&er off. They are ready to mate after two or three years.