Yes, Mavis, there are still some crocs in Vallarta, primarily in Marina Vallarta's El Salado estuary, but tourism development means you needn't worry about tripping over one. The best way to see them, while feeling safe, is to visit "Cipactli", the University of Guadalajara's well-run reptilarium at its Ixtapa campus about 15 minutes from the airport. It's free, and the preserve's bilingual staff love educating people - the American crocodile's only predators - about the valuable role these wide-jawed big fellas play in nature. As an added bonus, more than 40 iguanas live wild here.
Drive north past the bus terminal to the Las Juntas intersection. Turn right and go 3 km to Centro Universitario de la Costa. The blue and white "Ixtapa" bus enters the campus.