ST. PAUL, Minn. - A big discovery about dinosaurs was made at Macalester College in St. Paul.
A paleontologist figured out that a bone that belonged to one of the biggest dinosaurs ever was hollow.
The bone is called an osteoderm and it grows in the skin in modern reptiles.
Researchers believe the 65 million-year-old bone from a Rapetosaurus is hallow because the animal used up all the minerals and spongy bone as it got older as a way to survive extreme weather conditions.
"These animals are massive," said paleontologist Kristi Curry Rogers. "They needed to lay lots of eggs to survive and send their genes on to the next generation and we think they mobilized their bone mineral from inside these massive skin bones to help stay alive through the bad times they lived through."
Curry Rogers and a team of others discovered the bones in Madagascar in 1998.