It's a way of life worlds away from one that we know, which is why tribes have fascinated for centuries.

To celebrate the 45th anniversary of Survival International, the group has teamed up with The Little Black Gallery to launch a photography competition and raise awareness of tribal people and their way of life.

Open to both professional and amateur photographers, the competition invites images under three categories: land, diversity and way of life.

We've compiled some pictures in the gallery above from different tribes across the world, including those in Malaysia, Botswana and Brazil.

The 12 winning entries will be exhibited in The Little Black Gallery, and be included in Survival's 2015 calendar – while the overall winner will win an Olympus E-PM2 black digital camera.

The competition closes at the end of March. For more information, see