James Overby, age 10, of Hoyt Lakes, Minn., for his question:

DO ANIMALS HAVE NIGHTMARES?

We now know that cats and dogs and other furry mammals fall asleep more or less as we do. They have quiet periods of dreamless sleep and now and then they seem to have periods of dreaming. During these periods, it is possible to wake a person up and ask him what he was dreaming about. But naturally our animals cannot explain their dreams in human language.

Modern researchers are sure that the mammals and perhaps a few other advanced animals have dreams. But it is hard to be sure whether they are happy dreams or nightmares.  Sometimes a dog seems to moan in his sleep, which may mean that he is dreaming of scary things that happened during the day.  In any case, it seems only fair to give him a loving pat to make him feel more comfortable  just in case he may be having a nightmare.