How Do Spiders Give Birth to Live Young?
Many spiders don’t actually give birth to live young. Instead, they lay eggs in an egg sac. These eggs usually hatch within a few weeks, though they can take as long as a year. Some females will care for their baby for a short time before it’s ready to molt and leave.
Some species provide for their offspring by capturing and regurgitating prey. Other species may lay eggs for their offspring. A number of spiders in temperate regions overwinter in egg sacs. The egg sacs are distinctive in shape and color, and they can be used to identify a spider species.
Egg sacs are usually made of silk. They contain hundreds of eggs. Depending on the species, the egg sacs are shaped like a ball, a sphere, or even a cylinder. In some species, the egg sacs are shaped similar to the spinnerets in the bottom of the abdomen.
Female spiders lay many eggs to ensure that they can survive. Some of these eggs are wrapped in silk, while others are laid in a continuous stream into an egg sac. The egg sacs can range in size from four to 600, and the eggs may be green, white, or pearly.
Mothers of some spider species carry eggs on their backs or in their jaws. Others hang their egg sacs in a secure location, and some species even guard their egg sacs from predators.
Some spiderlings do not molt, but they do leave the egg sac after a few days of growth. They disperse by ballooning or walking. Although they are not harmful to humans, if a predator attacks them while they’re defenseless, it’s possible for the spiderling to die.