Prince William and Kate Middleton try to keep the lives of their three young children as private as possible, so it’s rare to get a glimpse at what their little ones are doing. That’s why it came as a welcome surprise when Williams revealed the latest obsession of his 5 year-old son Prince George, who is the heir to the throne.

During a visit to the Acorns Children’s Hospice in Birmingham this week, William revealed that George has started to become extremely interested in dinosaurs. While visiting the hospital, William met with children who are suffering from life threatening and life limiting conditions.

“Is that a triceratops?” William asked one small child. “George is obsessed with dinosaurs, we’re learning all about them.”

At the conclusion of his visit, William was given a special gift for George, Princess Charlotte, and Prince Louis. The hospice center gave William three dinosaur themed coloring books for his children, one of them called, “The Big Book of Dinosaur Coloring.”

The hospice center holds a special place in the heart of William, as it was opened by his mother, Princess Diana, in 1988. His visit was meant to mark the 30th anniversary of the opening, and he took the opportunity to meet with families who have used the center’s facilities.

In the past, William has said that George loves playing with helicopters and toy cars.

“I can always hear the wheels of those plastic tractors that George loves playing on,” said Prince Harry, William’s uncle.