Although the true longest neck is highly debated, it is thought that the Barosaurus, or “heavy lizard,” had the longest neck of any known dinosaur. The reason for the debate is that fossils of the Barosaurus are some of the rarest known. Because there are not many other specimens to back up the longest-neck claim, many scientists do not believe this animal is the winner. Even though there is still debate, the Barosaurus, which was related to the Diplodocus, did have an enormously long neck that was thought to be longer than the Brachiosaurus. Fossil remains of the Barosaurus have been found in the western United States and in Africa. The only mounted skeleton in the world of Barosaurus is found in New York City at the American Museum of Natural History; it is depicted rearing up on its hind legs, as if confronting a predator.

Most of the longest necks belonged to the sauropod (herbivore) dinosaurs, creatures that probably needed the longer necks to reach food in high tree branches. Other major contenders include the Brachiosaurus, a sauropod that reached a height of 40 feet (12.2 meters), with much of that height a combination of its long neck and front legs. Still another is the Mamenchisaurus, a sauropod with a 33-foot-(10-meter-) long neck.

To date, the longest neck in relation to its body belongs to the Erketu ellisoni, a sauropod with a neck more than 24 feet (8 meters) long. It lived in what is now Mongolia’s Gobi Desert about 120 to 100 million years ago.