Rattlers (1976)

A year or two ago, I saw the movie Sssssss.  That film had a mad-science main plot, but was enlivened mostly by the many scenes of snake-handling, which were kind of nerve-wracking even if you have no particular fear of snakes, and would have sent any ophidiophobe into the screaming meemies.

I mention Sssssss because of the contrast with this film: the snake scenes here simply aren't scary.  I mean, if you have a thing about snakes they probably are, but only because there are snakes on screen, not because the film does any kind of decent job of establishing a sense of menace.  The closest it gets is ironically in a scene featuring a cobra, rather than rattlesnakes.  A lack of scary snake scenes is kind of a big flaw for a movie about scary snakes, you know?

Rattlers kicks off with a trope that will be familiar to anyone who's seen a few killer critter movies: a rash of deaths all attributable to a specific kind of creature.  The animal in question is obvious from the title.  The local sheriff hires a herpetologist to investigate the snakes' sudden aggression, as well as a female photographer to assist him.

This being the 70s, the photographer's gender is the trigger for a tiresome subplot about women's liberation.  Tiresome because of course (a) the herpetologist is a sexist ass and (b) when the snakes turn up the woman is going to freak out and need to be rescued by the big strong man.  There's no guarantee a movie today wouldn't be just as filled with patriarchy, but it might not be quite so aggressive about it.

So anyway, they conduct their investigation, and begin to get an idea of why the snakes' behaviour has changed.  This is interspersed with various rattler attacks.  Those are probably an attempt to prevent tedium from setting in.  With the exception of a couple of inadvertently comical moments, they fail.

Eventually the cause of the trouble is confirmed, but the movie takes a sudden turn into shoot-outsville and the actual threat of the snakes, nor the reason for that threat, is ever actually addressed on-screen.  It's like the film-makers forgot they were making a killer critter movie.  But then, their critters were kind of forgettable.

There are much better options for 'when animals attack!'.  Heck, even Giant Spider Invasion is a step up from this.  Don't bother.