Spiders are invertebrates, meaning they have no back bone. Spiders are also members of the phylum arthropoda because they have an exoskeleton, paired legs, bilateral symmetry and a segmented body.
Spiders are also members of the class arachnida and are not considered insects because they have only two body segments and eight paired legs, according to Explorit Science Center. Insects only have six paired legs and can have up to three body segments, including the head, thorax and abdomen.
There are many different species of spiders, but some of them have unusual practices. For instance, the male of the red widow spider species will force-feed himself to his mate by crawling into her mouth parts, according to the Smithsonian. The red widow is a similar species to the black widow, of which the female eats her male partner without any need for special inducements.
Some species are a little more communal, actually working together to build a giant spider web that is used to capture their prey. When an insect or small animal is caught, the spiders share their food with each other.
When it comes to food, spiders can be fairly intelligent. The ogre-faced spider can weave a net that it hangs above spots where insects are likely to travel. As an unsuspecting insect trundles along, the ogre-faced spider swoops it up with the net for dinner.