At times an animal at play with another uses the same tactics and methods employed on its prey. Of course, the value of such practice for the tasks of later-life is evident. Dogs play hide-and-seek, tag, and various chasing games for hours without resting. Among the negroes of the South it is not uncommon to see a hound playing hide-and-seek with the little pickaninnies. I have seen a hound peeping in and out among a pile of brush to discover where the little ones were hiding, and at the first sight of a little black face, he would lay low in anticipation of a playful spring, or a sudden dash-away, with the expectation of being chased by his friends. At times he would suddenly disappear toward his home, and slyly slip around and approach the playground from an opposite direction. Every one who has owned fox terriers knows how they will crouch in the open grass and remain motionless, with quivering expectation for the other playfellow to arrive, and when the one in ambush sees the other coming he springs toward him, as though he were going to destroy him! And when the two come together, they attempt to seize each other by the necks, as they would do in a real conflict. A wrestle and tussle ensues and when utterly exhausted from this play, the tired dogs, like two fatigued children, run to their homes. Dogs are fond of playing ball, and will readily bring a ball or stick to their master when he has thrown it. They will also go into the water to bring out sticks that may have been tossed in for amusement. Eugene Zimmerman had a young fox terrier that would set a ball in motion, when there was no one to pitch it for him, by seizing it in his mouth and tossing it up in the air. Monkeys and jaguars will also play ball, and tame bears take great delight in wrestling, playing ball, and fighting mock battles. [Illustration: _American Museum of Natural History, New York_ THE MOTHER OPOSSUM IS NEVER HAPPIER THAN WHEN SHE HAS HER LITTLE ONES PLAYING HIDE-AND-SEEK OVER HER BACK.] [Illustration: THIS YOUNG FOX CAME FROM HIS HOME IN THE WOODS DAILY TO PLAY WITH A YOUNG FOX-TERRIER. HE IS NOW RESTING AFTER A ROMP.]