Alberta's Watchable Wildlife Spiders belong to a group of invertebrates called arachnids, all of which have 8 legs. There could be a thousand species of spiders in Alberta. All are predators, and many use different ways to catch prey. Some use a web, some chase, and others ambush their prey. In Alberta, only the black widow spider is dangerous to people.
Spiders play an important role in nature by keeping insect populations under control.
Spiders bite their victims and kill them with poison. They then suck out the blood. After the blood is sucked out, the spider injects enzymes that turn the insides of the victim to liquid, which the spider then sucks up. Spiders consume only liquids. Some spiders lay only a few eggs, others lay several hundred.