"Diplodocus" was a long-necked, whip-tailed giant and could grow up to 27 m long. It had an 8 m long neck and 14 m long tail. Its weight was approximately 22,680 kg. It had a short 6 ft long head. Its size helped protect it from other dinosaurs. It used its long neck to poke into forests because its body was too big. It is also believed to have knocked the trees down. The longest species is the "hallorum", which was thought to be the longest of all dinosaurs (now "Amphicoelias").