Scientists Uncover Clues About Giraffe’s Long Neck

A new study of fossil cervical vertebrae reveals the evolution likely occurred in several stages as one of the animal’s neck vertebrae stretched first toward the head and then toward the tail a few million years later. A total of 71 fossils of 9 extinct and 2 living species of giraffes were examined. According to researchers, the C3 vertebra of today’s giraffe is nine times longer than its cross measurement, almost as long as an adult human’s humerus bone, which can stretch from the shoulder to the elbow.

The second stage was characterized by an elongation on the back or caudal portion around one million years ago. They found that two species – Prodremotherium elongatum, which lived 25 million years ago and was potentially an ancestor of modern giraffes, and Canthumeryx sirtensis, which was a giraffe ancestor that lived 16 million years ago – both had elongated necks.

To reach this conclusion, researchers analyzed fossils of giraffe cervical vertebrae. Now, a study suggests the giraffe didn’t simply grow its long neck suddenly, or even steadily over millions of years.

It may sound like the plot of a whimsical tale by author Rudyard Kipling, but scientists have finally unravelled how the giraffe got its long neck.

In addition, giraffes are not the only animals to have evolved long necks.

“We also found that the most primitive giraffe already started off with a slightly elongated neck”, said Danowitz.

Melinda Danowitz, one of the researchers at the New York Institute of Technology who conducted the study, said surprisingly it appears the animal’s necks began growing far earlier than had been thought.

The long iconic neck of giraffe is the one of the most discussed topics among scientists and several evolutionary theories are proposed to explain the evolution of this elongated giraffe neck.

Now that researchers know that the giraffe’s neck is at least 16 million years in the making, they can continue trying to figure out what drove the evolution toward longer necks.

Male giraffes also use their long necks to battle each other in violent fights over females. Apparently, modern species of giraffes developed this new physical characteristic 16 million years ago.

However, the most important discovery came after the researchers studied anatomical features of separate fossils and compared them to the evolutionary tree.

An ancestor of the giraffe split into two evolutionary branches, one leading to the okapi with its short neck and the other branch leading to the giraffes. Today, the C3 vertebra of common giraffe is nine times longer than its width. But rather than evolving a long neck, it has a neck that has shortened again.