Archaeologists have discovered what is believed to be the smallest skull belonging to a Diplodocus, telling us more about how these giant dinosaurs grew.

Published in the journal Scientific Reports, an international team of palaeontologists investigated the skull found in Montana in 2010. It is thought to belong to a young Diplodocus (nicknamed Andrew after philanthropist Andrew Carnegie) that lived on Earth more than 150 million years ago during the Late Jurassic Period.

Only eight skulls of this creature – part of the giant sauropod group of dinosaurs – had been found before, many of which were from adults. But this skull, just 24 centimeters (9.4 inches) long, fills an important gap in our knowledge of these majestic beasts, which could grow to up to 30 meters (100 feet) long.

“This skull and the knowledge locked away within it is helping us further understand the intimate details surrounding the life history of these remarkable animals,” lead author Cary Woodruff, a PhD student from Royal Ontario Museum, said in a statement. “How a baby Diplodocus that hatched from an egg no bigger than a cantaloupe grows up to be 100 feet long within 30 years is astonishing in and of itself – and this skull, like a puzzle piece, is helping us piece together how this rapid growth was even possible.”

Despite the huge size of these dinosaurs, their skulls were relatively small. Adult skulls are more than twice the size of this skull though, giving us an insight into the rapid growth of these creatures.

One key difference between this and an adult skull was the number of teeth – adults have 10 or 11, whereas this juvenile had 13. Its teeth, spoon-shaped compared to an adult’s peg-like teeth, were also found to extend back along the jaw, unlike adults that have teeth just at the front.

This suggests that the diet of Diplodocus changed as it got older, allowing the younger animals to eat a wider variety of plant types to feed their growing bodies.

“From this little skull it would seem that a young Diplodocus took Popeye’s message to heart; if you eat your greens you’ll grow big and strong,” said Woodruff.

There are some questions about the veracity of the skull, however. Speaking to National Geographic, Kristi Curry Rogers, a paleontologist at Macalester College in Minnesota, said the skull was missing parts of its cheek, palate, and lower jaw. As such, its status as a member of the Diplodocus family is not definitive.

Still, if it is a Diplodocus, it provides us with a fascinating look at how these animals grew. If you’d like to check out the skull yourself, it will be on display at the Cincinnati Museum from November 11 this year.