Believe it or not, scientists now think baby Tyrannosaurus rexes looked like fluffy hatchlings. Of course, that adorable creature would transform into a full grown eating machine.

In fact, an adult Tyrannosaurus rex could weigh up to seven or eight tons, and were forty feet long.

The ferocious rock star of the dinosaurs is the focus of a new exhibition at the American Museum of Natural History, which opens to the public on Monday. “T. Rex–The Ultimate Predator” was curated by Mark Norell, world-renowned Chair of Paleontology at the museum, which is at forefront of the T. Rex world.

The first skeleton of Tyrannosaurus rex was discovered in 1902 in Hell Creek, Montana, by the Museum's famous fossil hunter Barnum Brown. Another one found six years later is a popular stop for museum visitors.

“If people know about one dinosaur, it’s T. rex. And, certainly, T. rex has been a fixture at this museum since it was put on display in the early part of the 20th Century,” Norell said.

The T. Rex exhibition is a very appropriate kick off to the museum’s 150th birthday celebration.

Museum President Ellen Futter says T. Rex may have lived 68 million years ago, but they never get old.

“Because they are so fascinating, they are such a gateway to learning,” Futter said. “Such a gateway to awakening curiosity and wonder.”

To find out more about the T. Rex and the museum’s 150th birthday events, head to AMNH.org.