American black bear estrus and parturition in the Alleghany Mountains of Virginia

作者：Bridges Andrew S^*; Vaughan Michael R; Fox Josephine A

来源：Ursus, 2011, 22(1): 1-8.

DOI：10.2192/URSUS-D-10-00008.1

• American black bear
• birth
• breeding
• cub
• estrus
• parturition
• reproduction
• Ursus americanus
• Virginia

Timing of parturition and, to a lesser extent, estrus, are rarely explored aspects of American black bear (Ursus americanus) reproductive ecology. The Cooperative Alleghany Bear Study was an intensive 10-year multi-faceted research project conducted on 2 study areas in western Virginia. We examined timing of estrus based on 430 observations of 326 lone (without cubs at the time of capture) female bears from late May-August, 1994-2002. We estimated parturition date for 383 cubs from 150 litters born from 996-2003 to 99 individual females ranging from 3-24 years old. Bears were documented in estrus from late May through August with a peak during early July. Parturition dates ranged from late December to mid February with most births occurring in mid January. Three- and 4-year olds gave birth, on average, 12 days later than older bears. We suggest parturition date likely affects den exit date and perhaps cub survival, an area requiring further inquiry.

• 出版日期2011