12 (1 Dozen OF The Same Design) POSTCARD OF BLACK BEAR CUB UTAH Black bear cubs are born during the hibernation period in late January. When born, they weigh about nine ounces and are the size of a stick of butter. From this point on, they grow very quickly weighing 15 to 20 pounds by May and about 75 pounds by the end of the summer. A fully grown male black bear usually weighs about 500 pounds. Photo: Donald Jones Postcard size 4 x 6