Timber rattlesnake females produce very few offspring in their lifetime.
They don't start reproducing until 7/11 years old, only reproducing every 3 to 4 years for their 25-year lifespan. In fact, 60 % of females only reproduce once.
Because of this, they need to ensure the highest quality males father their limited number of offspring.
The female will wait for the males to come to her. The males then need to impress her with a special three-step "dance." You can see it here!
Females have two vaginas and two clitorises. The males also have two penises. They use both during mating.
Photo by Devon Bradley
https://live.staticflickr.com/1886/42628627120_2acc5dc41d_b.jpg
The female will generally mate with several males during the breeding season.
She will store all the sperm for at least over winter, but potentially for years.
Come springtime, the female can select which male's sperm is the best to use to fertilise her precious eggs.
Diagram of the special pockets in the vagina that store sperm.
Image from Sever and Hamlett, 2002.
References and Further Reading