Spiders: True or False? Spiders evolved more than 300 million
years ago, long before dinosaurs walked the Earth. - True. Those
ancient spiders didn't build webs but sought the safety of
burrows dug underground. There, they were shaded from the Sun
and protected from predators. There are as many species of
mammals as there are spiders. - False. While there are about
6,000 mammal species, scientists have identified over 43,000
spider species so far. There may be at least as many still out
there to be discovered. Every spider sheds its exoskeleton, the
inflexible outer shell, several times during its life. - True.
Most stop molting once they reach maturity, though females from
some relatively primitive families of spiders continue to do so
throughout their lives. Spiders have poor eyesight. - True.
Nearly all have eight simple eyes--consisting of one lens and a
retina--arranged in different ways but, for the most part, don't
see very well. In most cases, spiders use other senses, like
touch and smell, to help ca