“Zoo” initially ran on CBS for three seasons, airing Tuesdays at 10 pm. The series ends on a cliffhanger, with a threat of a zombie apocalypse added to the animal apocalypse already going on. The events of the series became more and more bizarre, with Jackson seeming to fall into insanity, becoming able to control animals telepathically, and more. In the second and third seasons, they encounter a wide variety of new and strange creatures, such as a 70-foot snake that can turn invisible, burrowing ostrich-vultures, razorback wolves, and a wooly mammoth-rhinoceros hybrid. They believe they have developed the cure, but it turns out that the virus has mutated and the animals have gone berserk all over the world. During the first season, the team travels the world trying to find an antidote for the virus that has infected the animals, causing their strange behavior. The ongoing plot for “Zoo” was rather intricate and at times absurd.
The series was written by Scott Rosenberg, Jeff Pinkner, Andre Nemec, and Josh Appelbaum. The original basis for “Zoo” was a novel of the same name written by James Patterson (who also served as an executive producer on the show) and Michael Ledwidge, although the series quickly moved past the events of the novel and began covering new plot elements.