先兽（Poebrotherium）是已灭绝的骆驼，生存于3500万年前始新世晚期至渐新世早期的北美洲。

先兽长1米，外观像现今的骆驼而多于牠的后裔原疣脚兽，头颅骨则像大羊驼。牠的四肢都有蹄，比原疣脚兽更适合奔跑。

Poebrotherium is an extinct genus of terrestrial herbivore the family Camelidae, endemic to North America from the Eocene through Oligocene 38—30.8 mya, existing for approximately 7.2 million years.