How Many Cubs Does A Black Bear Have?
Litter size ranges from 1 to 4 young, averaging from 1.4 in Arkansas to 3.0 in Pennsylvania. First litters may be small, sometimes a single cub. Two or 3 cubs are typical thereafter. Five-cub litters are uncommon; extraordinary litters of 6 cubs have been reported in Manitoba and Pennsylvania. Average litter sizes in 2 Massachusetts study areas were 2.0 and 3.0. Two 5-cub litters have been reported in Massachusetts, once in the den and another in the field. Field observations are probably valid, as natural adoption of cubs is rare.
The sex ratio at birth is commonly 1:1. However, the sex of cubs is correlation to the mother's weight and to litter size. The number of males is commonly higher with heavier mothers, but lower as litter size increases. In one Minnesota study, 82% of single litters were male, while only 52% of 3-cub litters were males. One exceptional Massachusetts sow, 13 yrs old and 175 lbs., produced a litter of 5 male cubs.
During the denning period, sows may produce more than 50 lbs. of milk, metabolized from body fat. This milk is rich in fat and protein and nearly twice as high in kilocalories (per 100 ml) than either human or cow milk. Cubs may weigh up to 9 pounds by den emergence. Massachusetts cubs normally reach 13 to 20 lbs. by early July.
References: Alt 1980, Alt 1984b, Clark 1991, Elowe 1987, Hock and Larson 1966, Kolenosky and Strathearn 1987a, McDonald and Fuller 1998, Noyce and Garshelis 1994, Rowan 1947.
Posted by: Kelly