Snakes hibernate in the winter in dens. Dens are areas free from frost and can be found in narrow crevices in rocks, animal burrows, holes under trees and stumps, under wood piles, and occasionally in basements. During the first warm days of spring snakes emerge from their dens and begin sunning. After temperatures consistently stay above freezing snakes will begin searching for food and move gradually to their summer range and birthing areas. Most snakes mate within a month of leaving the den, but some species mate in the fall.
Many snakes lay eggs, but about a third of the species in Maryland bear live young.
Eggs are usually laid in warm, damp places. They are tough and leathery and may number from a few to a few dozen, depending on the species. Very few species guard nests, and all young, whether live-born or hatched, are independent at birth. Live- born young will remain near the female for at least a week or more after birth. In rattlesnakes and copperheads, the young are believed to follow a chemical trail left by the adult female back to the den.