crayfish dinosaur cousinsNow, I don't have much experience with fishing -- not in lakes or ponds or rivers or the deep blue sea -- so I'm not 100% certain about this, but I'm guessing that when you go fishing in a stream in your backyard, you probably have fairly low expectations about what you might catch. Like cousins Eric Stamatin and Andrew Gainariu, both 11 years old, who were only half-hoping to nab a couple of crayfish in the creek behind Eric's house (which extends from the middle branch of Michigan's Clinton River). As usual, the crayfish weren't biting -- so the kids gave up and decided to build a dam instead. No biggie.

That's when they came across what they thought was a big rock. But, as you've probably already guessed (since why would a story about kids finding a rock make headlines?) it wasn't a rock at all.

Nope, that "rock" was a 13,000-year-old mastodon bone -- specifically, a specialized second vertebrae behind the skull in the spinal column of an American mastodon (the animal, exitinct for 10,000 years, was once native to the area which is now Michigan).

Naturally neither Eric nor Andrew knew exactly what type of bone they'd discovered right away. So began a bitter (kidding!) feud that's yet to be settled:

"I said it's obviously a dinosaur bone, but my cousin said 'no,'" says Andrew, who adds, "I told Eric, you really want to go there? I bet 100 bucks it is a dinosaur bone, because I have always been fascinated with bones."

Who's sorry now, huh? Well, except Eric never actually had to hand over the dough, because the bone wasn't technically a dinosaur bone. But the boys still have plenty to squabble over, like what to do with the mastodon bone now that they know what it is (a geologist and paleontologist from the Cranbrook Institute of Science identified the mysterious object for the family).

"Andrew said maybe we can sell it, and that we could be famous ... but I guess we are famous already," said Eric (clearly the less mercenary of the two).

"I have been thinking of selling it and making money off it," agreed the (money-hungry) Andrew, "but who is going to pay 2,000 bucks for a bone?"

Um ... yeah, who's gonna pay $2,000 for a bone? Pffft. Better just let me take it off your hands. And I'll only charge you 50 bucks, how's that? Mwahahahahaha!!

What's the craziest thing your kids ever found in the backyard?

Image via CNN