Megacyon is thought to have evolved from mainland species of Xenocyon, with Megacyon being even larger than mainland Xenocyon species. Some authors have subsumed Megacyon into Xenocyon. Megacyon is thought to be the ancestor of the much smallerMececyon known from younger deposits on Java. Megacyon are currently around the 49-54 kilogramsizerange due to their evolution and niche overlapping with tigers. As tigers and Megacyon had a 100% niche overlap, Megacyon evolved to be smaller in size in order to avoid this niche overlap for the species survival.