A house that will soon be up for sale in southern Michigan may have mammoth or mastodon bones at the bottom of its backyard pond.

Steve Dodge found the bones and ivory tusks of a giant elephant-like animal after excavating his backyard to build a pond 10 years ago, the Jackson Citizen Patriot reported.

"I knew that rib bone was from nothing I'd ever met before," Dodge said.

He said he never publicly spoke about the bones until now. But now that he and his wife are moving to Detroit, he said the bones shouldn't be kept a secret.