This intriguing entry into the revenge-of-nature cycle of the 1970s shouldn't work, but it does. The script has some problems that would seem insurmountable under normal circumstances: the scientific explanation for the animals' sudden psychosis isn't ever put forth in a credible manner, the characterizations are pretty basic, and some of the subplots, namely the one with Leslie Nielsen's character suddenly going crazy, are a bit too goofy to really work. That said, Day of the Animals works quite effectively at a visceral B-movie level thanks to plenty of technical polish on both sides of the camera. Veteran B-auteur William Girdler directs with a considerable amount of style, using the scope format to give the visuals a grand look and handling the animal-attack scenes with vigor and solid timing. He also uses a fantastic B-movie cast that adds some much-needed heft to the characterizations; Christopher George and Michael Ansara make good square-jawed heroes and Leslie Nielsen turns in a delirious, over-the-top villainous performance that is hard to forget. In short, Day of the Animals is definitely a B-movie, but it's a very entertaining and viewer-friendly one for fans of the form. Anyone who enjoyed Frogs or Kingdom of the Spiders will definitely get a kick out of this film.