Black widows are carnivorous and cannibalistic in nature. The way the black widows eat can seem gross to some people, but is actually one of the interesting facts about the black widow spider. These spiders puncture the prey's body using their fangs and inject digestive enzymes into the dead body of the prey. Then the black widows liquefy the prey's body and suck-up the fluid! The black widows, despite being poisonous, have many predators. Black widow spiders are the favorite food of the praying mantis. There are also some birds which eat these spiders and often end up with an upset stomach!