Vandals used a hammer to smash a 115-million-year-old three-toed dinosaur footprint in a national park in Australia. Park rangers at the Bunurong Marine Park discovered the damage to the theropod footprint while taking a school group on a tour.

The one-foot wide print was found in 2006 and deliberately left in place to allow visitors to see it in its natural state in one of the world’s few ice-age dinosaur sites.

"It is so disappointing,” Parks Victoria ranger Brian Martin told ABC News.

“It's a popular, significant site. The rock there is reasonably hard so it looks like it's been hit with a hammer and pieces of the rock around the edge of the footprint have been broken away.”

The identity of the culprits and the possible motive remain unknown, but it appears the vandals were familiar with the footprint.

“For someone to damage it intentionally, you'd have to have a rough idea of where it is because seaweed grows on the rock platform and it looks like a normal rock until you look closely and see the outline of the footprint," Mr Martin said.