FOOD-INTAKE AND MASS GAIN OF HAND-REARED BROWN BEAR CUBS

Five orphaned European brown bear cubs (Ursus arctos) from 3 litters w ere hand-reared from the ages of 1-4 months. Body mass initially range d from 1.7 to 2.8 kg. Growth rates were monitored with reference to di et. Over a period of 3 years, 6 different feed formulas were used. The first 4 formulas were given with bottles until an average age of 133 days. Conversion to mass in the first 10 months ranged from 3.5 to 32. 0 g of food per gram of body mass (or 38.1-192.6 kJ of gross energy/gr am body mass), and was affected by type of diet. High fat content incr eased, whereas high carbohydrate content decreased the conversion rate s. Formula 3, with 12.0% protein, 23.9% fat, and only 0.2% carbohydrat es, simulated values found in bears' milk and produced the best growth rates. Formula 6 (bread, fruits, and meat) was used from ages 7 to 35 months, and over this period, the efficiency of gross energy conversi on decreased gradually, by an eventual factor of 3.8. Hand-reared cubs ranged from 1.3 to 2.7 times heavier than 17 wild cubs measured at ma tching ages. Wild mass is probably limited by maternal hibernation, an d by the largely herbivorous nature of the diet. (C) 1993 Wiley-Liss, Inc.