The Polar Bear, (_Ursus maritimus_).—In nearly every collection of living bears the individuals of this species are the most showy and attractive. Their white coats quickly catch the eye of the visitor, and whether young or old, they are generally the most active and playful of all captive bears. In cold weather, when other bears lie in the sun, or, if permitted, curl up in the straw of their sleeping dens, the Polar Bear will disport himself in the freezing cold water of his swimming pool, and joyously play with a cake of ice until the sight of it makes one shiver. The Polar Bear Den is situated at the north end of Rocking-Stone Hill, about two hundred feet from the north end of the main series of Bear Dens. It is reached by descending the steps leading toward the Beaver Pond, and turning to the right. From the Rocking-Stone Restaurant, the Polar Bears are quickly reached by descending the hill toward the north. Although the Polar Bear inhabits practically the whole of the Arctic Ocean and its numerous islands, it is by no means the most northerly warm-blooded mammal. Nansen found fox tracks at 85° N., but the most northerly bear observed was on the 84th parallel. The favorite home of this animal is the edge of the great polar ice cap, where Neptune and the “Frost King” wage continuous warfare. He seldom ventures more than a day’s journey inland, on any shore. In winter, as the edge of the ice-pack moves southward, and in summer when it retreats northward, he follows it in order to keep in touch with the ringed seals and walrus that also go with it. [Illustration: POLAR BEAR “SILVER KING.”] The power of the Polar Bear to resist ice-cold water—nay, even to enjoy it—may fairly be regarded as one of the wonders of Nature. On the coast of Alaska this strange creature will plunge into the Arctic Ocean and swim miles from shore, through tossing fields of broken ice, and wherever the mother leads, her cubs follow. In the Autumn of 1910, the sealing steamer “_Boethic_” arrived at New York bringing two adult Polar Bears that were captured in the summer of that year by Mr. Paul J. Rainey. Both animals were presented to the Zoological Society, and the largest one called “Silver King” occupies the cage that was specially built for the polar bears, and the female is exhibited in very comfortable quarters, built for her near that installation. Owing to their savage temper neither of these bears ever can be kept with other bears, nor can any keeper ever enter the cage of either. “Silver King” weighs 880 pounds and is probably the largest Polar Bear ever captured alive and unhurt. While the female is not as large as “Silver King,” she is in every way as perfect a specimen.