The long neck of the giraffe is certainly its most distinguishing feature, accounting for about half its height, and scientists have since found a pretty amazing reason why it has this long neck.

Researchers recently sequenced the giraffe genome for the first time, and the results are interesting: giraffes didn’t grow out their necks by adding vertebrae like some long-necked birds — rather, the necks simply gradually stretched out while sticking with just seven vertebrae, according to a Penn State statement.

But how did the giraffe do this, considering the incredible obstacles when it comes to muscles and the skeletal structure, not to mention blood circulation?

For one thing, the giraffe evolved an oversized left ventricle and reinforced circulatory system that allowed the body to pump blood 10 feet into their brains. They also have blood vessels that are capable of regulating blood flow when they bend down to drink to avoid sudden pressure changes.

Scientists also studied the okapi, a sort of horse-like creature with a long neck that isn’t quite as exaggerated, which is the only other surviving member of the Giraffidae family. Scientists believe the okapi split with the giraffe 11.5 million years ago, sending the giraffe on its tremendous neck growth spurt.

“The giraffe’s stature, dominated by its long neck and legs and an overall height that can reach 19 feet (~ 6 m), is an extraordinary feat of evolution that has inspired awe and wonder for at least 8,000 years — as far back as the famous rock carvings at Dabous in the Republic of Niger,” Douglas Cavener of Penn State University, who led the research team with Morris Agaba of the Nelson Mandela African Institute for Science and Technology in Tanzania, said in the statement. “The evolutionary changes required to build the giraffe’s imposing structure and to equip it with the necessary modifications for its high-speed sprinting and powerful cardiovascular functions have remained a source of scientific mystery since the 1800s, when Charles Darwin first puzzled over the giraffe’s evolutionary origins.”