after three seasons http://www.hollywoodreporter.com/live-feed/zoo-canceled-at-cbs-3-seasons-1051252
Not a surprise, ratings were down a lot and it was expensive to produce. Too bad it ended on a cliffhanger. I like the first season but it got too weird later on. Shame that The Night Shift was cancelled too, really liked that one.
I didn't watch the third season - I may never now.