Deborah Black, age 7, of Ladner, B.C., Canada, for her question:

Why does a camel have a hump?

We all know that the stately camel can go without a drink of water for several days, even in the hot desert. Some people think that he carries extra water in his hump. But this is not so. He takes along his water in a very special stomach. His hump can take along an extra supply of food. However, it is not stuffed with hay or any of his other favorite foods. When he gets a chance, he eats and eats and some of the food is changed to fat. This extra fat is stored in his hump.

Before he starts across the sandy desert, the camel's master lets him eat and drink all he wants. Little pockets in his special stomach are filled with water and his hump is firm and stiff with fat. The water lasts several days. The food can last longer. But as his body uses up the stored fat, his hump gets softer. If he misses very many meals, his soft hump sags over to one side.