Natural horror was not a sub-genre this scary movie connoisseur cared for until 2008’s The Ruins, a film about plants (“plants? !” we hear you cry) with a majestic scene where a vast chorus of chittering vines greet some not-so-final girls in a Mayan temple. Seriously acted and slick to look at, it has nothing in common with the hundreds of comedies-disguised-as-horrors/abysmal B-movies about sharks, piranhas, dogs, etc. Because, for all its campy absurdity – the titular character is an adorably T-shirted chimp called Ben, after all – what heightens Primate’s horror is its plausibility. That animals can have a sense of humour is pretty scary, when you think about it.