Silk is a fibrous protein that is light and elastic, but it is stronger than steel fibers of the same thickness. All spiders use a unique form of mating, in which the male transfers sperm to the female using specially modified appendages near the mouth, called pedipalps. Females lay eggs in batches, wrapping the batches in silken egg sacs. In some species the female carries the sac with her and in other species she merely deposits it in a safe place and abandons it. The spiderlings hatch within the sac and then leave the sac to begin feeding.
Most spiders live only one or two years.
They will molt 4-7 times as juveniles, no longer grow any larger after they mature into adults and so do not molt. Most rely on venomous bites to subdue their prey. Spiders in the family Uloboridae do not have venom glands at all, but merely bite their prey to subdue them. Also, some spiders have become specialized for feeding on certain types of prey. The flower spider, Misumena vatia , will change the color of its large abdomen, over several days, to match the color of the flower.