Whereas modern apes exhibit a rich repertoire of locomotory modes ? from the highly acrobatic brachiation employed by the arboreal gibbon to the gorilla ' s terrestrial knuckle walking ? early miocene apes were obliged to travel along tree branches on all fours 虽然现代猿的移动模式花样繁多，例如长臂猿在树间以双臂移动身体、大猩猩在地面上以上肢手背关节支撑体重，但是中新世早期的猿类都以四肢在树枝上活动。
