This is the time of year when female Prairie rattlesnakes in Alberta, SK & Mont become pregnant. They mated last summer in July, Aug or Sep but they didn& #39;t become pregnant then. The sperm was stored in a cavity known as a spermathecae and was used to fertilize the ova right now.
The ova weren& #39;t mature at the time of mating but are at this time of year. Once the eggs are fertilized, the female leaves the over-wintering den and seeks out a birthing den or rookery where she spends her summer maturing the eggs developing within her body. In late summer,