Arrowtongues are bipedal predators that inhabit Darwin IV. They use their arrow-like tongues to attack and impale their victims, and are known to run close to 40 mph when chasing prey, which includes Gyro-sprinters and other herbivores. This creature is similar in size to the Tyrannosaurus Rex of Earth, and has been theorized to be the result of a convergent evolution.

In his book Expedition, Wayne Barlowe states that Arrowtongues are around 8 meters (26 ft) tall.