REPRODUCTION OF THE TIMBER RATTLESNAKE (CROTALUS-HORRIDUS) IN THE APPALACHIAN MOUNTAINS

I studied the reproductive ecology of the timber rattlesnake (Crotalus horridus) during a 19-yr period in the Appalachian Mountains in NW Virginia and nearby areas. The short (5.3 mo) and cool active season places constraints on growth and reproduction. Gravid and postpartum females averaged 93 cm (76-112 cm) total length. Mating occurred in late summer (observations from 21 August to 18 September) coincident with the onset of follicular yolking. Ovulation took place in late May and early June of the following year. Postpartum females with litters were seen from 4 August to 16 October. The mean age of probable first-time reproducers was 7.8 yr (5-11 yr) with 7- and 8-yr-old females making up 56% of the first-time reproducers. I found a mean interval of 3.08 yr (2-4 yr) between successive reproductions for marked females. The proportion reproductive by age class ranged from 17% for 5-yr-olds to 66% for 10-yr-old and older females. The high proportion (60%) of the adult female sample reproductive during the year of capture is attributable to greater catchability of gestating females. Only 32% of the more-representative April-May sample was gravid. Because of vagaries of the weather and synchronization of the breeding cycle among females, reproduction occurred in pulses with the proportion of mature females reproducing estimated to range from 10-75% per year.