Some birds are called birds of prey because they catch, kill, and eat other animals. The hawk is one such bird of prey. If a hawk is caught when it is young, it can be tamed and taught to hunt, somewhat as a hunting dog is used. Many natural pearls contain blemishes that lower the pearl's value. Since pearls are formed in layers by sea-pearl oysters, an expert can remove the outer blemished layers of the pearl and leave a perfect pearl.
Snow is really warmer than the subzero air that kills many plants.
Thus snow insulates the plants it covers from the killing cold. One observer noticed that some shrubs bloomed only up to the depth of the winter snow that protected their buds. A convertiplane is a type of aircraft that flies like a conventional plane but lands and takes off vertically like a helicopter. It used to be believed that when an old elephant felt that death was approaching it went to an elephant graveyard to die. Ivory hunters were never able to locate such graveyards.