Some dinosaurs needed long necks to reach high in the trees, loading their enormous guts with enough roughage to supply a small forest. These were the dinosaurs with the longest necks, so lengthy in stature that their height reached that of a four-story building while standing upright. Giraffes had nothing on these prehistoric skyscrapers.

And there were many species of long-necked dinosaurs. While each one had a long neck, they all had different traits that set them apart. Here are five species of this enormous dinosaur.

 1. Mamenchisaurus sinocanadorum

Mamenchisaurus sinocanadorum is known as the longest-necked dinosaur ever found in the fossil record, as described in a recent paper published in the Journal of Systematic Palaeontology. The specimen was found in rocks dating from 162 million years ago in the Xinjiang Uygur Autonomous Region of China. Its neck is 50 feet long or about six times the length of a giraffe’s neck. 

This sauropod may have the longest neck of any animal ever to live on Earth and a gigantic body to match. Mamenchisaurus survived by standing in one place for long periods while munching on vegetation high up in the tree canopy. Its neck likely also helped the species shed heat, similar to an elephant’s ears. 

While these animals are so huge that it seems impossible that they could thrive, their long necks were actually an adaptive feature that allowed them to survive for millions of years. Long-necked dinosaurs like Mamenchisaurus survived until an asteroid rammed into Earth 66 million years ago, abruptly ending the age of dinosaurs.

Read More: Can We Protect the Planet From an Asteroid Speeding Towards It?

 2. Brachiosaurus

This huge herbivore lived in North America between 156 and 140 million years ago during the Jurassic period. Weighing in at 28 tons and measuring 80 feet long, Brachiosaurus was too enormous to run away from predators like Allosaurus, so its sheer size served as a means of protection.

It also required a massive gut to digest the copious amounts of trees that it needed for survival daily. This ancient beast’s comparably small skull likely housed a small brain—but with a body that large, brains were just a side note to survival.

 3. Diplodocus

Diplodocus (Dippy) was another long-necked, long-tailed herbivore. Scientists think that ligaments that ran from the hip all the way up the back of the neck would have allowed Dippy to lift its enormous neck without having to use any muscles. It was around the size of four elephants standing trunk to tail and might have been even longer. 

New research published in the journal Paleontology and Evolutionary Science has shown that long-necked dinosaurs like Diplodocus could have had longer necks than we previously thought because we’ve never been able to put together all the neck and tail vertebrae from these species to know their full length.

 4. Giraffatitan

Giraffatitan’s specimens are found in Tanzania. Similar to the Brachiosaurus, though thought to be a distinct species. Prior to research findings that highlighted differences in its morphology, the species was called the African Brachiosaurus.

It lived in the Late Jurassic period between 154 and 142 million years ago. Like many other long-necked dinosaurs, it was known as a “high browser,” using its flat, rounded rows of teeth to mow off soft foliage from the tops of trees.

 5. Apatosaurus

This giant sauropod lived between 156 and 151 million years ago during the Jurassic Period and has been found in North America and Europe. At about 75 feet long and weighing in at 41 tons, it’s known for its whiplike tail. Like other sauropods, Apatosaurus was a terrestrial species that survived on land and was not aquatic. 

It’s thought that its bones were hollow, like other huge sauropods, which reduced the weight put on its joints. It was initially thought that Apatosaurus’ tail actually cracked like a whip, but now scientists dispute this notion because it would have caused undue damage to the tail vertebrae over the lifetime of the species. Only one Apatosaurus skull has ever been excavated, and it’s on display at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.

Read More: What Can Plant-Eating Dinosaurs Teach Us?