THEORIES Some extinction theories are-viruses. Although it is unlikely that a single virus caused the extinction of the dinosaurs, it is possible that multiple viruses did, but, it would have taken longer to kill them off. Much longer. Another theory lies beneath the waters of the Yucitan (yoo-kih-taan) Peninsula in Mexico. The crator is thousands of miles deep, and wide. That is the most reasonable theory of dinosaur extinction. Though other theories do exist, these are the main two.