Ark: Survival Evolved (stylized as ΛRK) is an action-adventure survival video game developed by Studio Wildcard in collaboration with Instinct Games, Efecto Studios, and Virtual Basement. It was released in August 2017 for PlayStation 4, Xbox One, Microsoft Windows, OS X and Linux. In the game, players must survive being stranded on an island filled with roaming dinosaurs and other prehistoric animals, natural hazards, and potentially hostile human players. The game is played from either a third-person or first-person perspective and its open world is navigated on foot or by riding a prehistoric animal. Players can use firearms and improvised weapons to defend against hostile humans and creatures, with the ability to build bases as defense. The game has both single-player and multiplayer options. Development began in October 2014. The development team conducted research into the physical appearance of the animals, but took creative license for gameplay purposes. One of the game modes, Survival of the Fittest, was released as a free standalone game in March 2016. Egypt-based developer Instinct Games was hired to facilitate the game's development. Several expansions to the game have also been released as downloadable content: The Center, Primitive Plus, Scorched Earth, Ragnarok, and Aberration.