It’s not uncommon for actors to be rendered near-unrecognisable by make-up artists, but Sasquatch Sunset really does take it to another level. Performers of the calibre of Riley Keough and Jesse Eisenberg are buried somewhere beneath layers of latex and body hair, and speaking solely in grunts. An audacious, original and unashamedly out-there achievement, this film is the brainchild of siblings David and Nathan Zellner, best known for Kumiko, The Treasure Hunter.

Sitting somewhere between a chamber piece and a nature documentary, and featuring plenty of calamitous comedy, Sasquatch Sunset follows four of the titular beasts in the wilds of northern California: an alpha male (Eisenberg), his mate (Keough), their child (Christophe Zajac-Denek), and a rival male (Nathan Zellner) who falls out with the pack after showing sexual aggression towards the female. As they roam, they begin to notice more and more signs of human activity.

The film revels in the clan’s rituals and routines, their very public intimacies, and moments where they commune with, or are antagonised by other creatures. It ambles along amiably for a while in this way, soaking up the serenity of their surroundings and staging a number of hilarious, crude and appropriately animalistic sequences. However, tension and jeopardy are introduced very effectively, while there’s an unforgettable encounter with the music of Erasure.

The lack of dialogue is surprisingly unproblematic, so engrossing and wonderfully expressive are the performances, while a superb score from The Octopus Project enhances emotion and the film’s shifts in tone by employing what sounds like a huge variety of instruments. Sasquatch Sunset sheds much of its silliness as the film progresses, building to something disarmingly moving. And though no words are uttered, it speaks volumes about what’s wrong with humanity.

Sasquatch Sunset is screening at Picturehouse Central, London, Saturday 8 & Sunday 9 June, as part of the Sundance Film Festival; on general release from Friday 14 June.