Imagine getting the chance to take part in an exciting adventure in some of the roughest and most remote waters in the world.
That's what happened to Callum, who's one of a few lucky kids involved in the latest series of the CBBC adventure show, Serious Ocean.
Callum is part of Serious Ocean
Callum's mission was to help scientists learn about the mysterious elephant seals in Chile, South America.
Experts don't know much about the animals, but four years ago discovered some of them head to the southern tip of Chile to breed.
So Callum headed south with the scientists to help them tag one of the animals so its journey can be tracked by satellite.
"I was quite excited to go and tag the seal because it's something that you don't get to do every day," he said.
Callum glues the tracker to the seal
When the tracker's stuck on the seal, the signal is beamed back to scientists to let them follow its every move.
But first, they needed to find a suitable pup.
"We spotted a young female pup, but at six months old she's already huge and tricky to catch," said Callum.
"One of the scientists made the seal feel sleepy so he could attach the tracking device. It's also a rare chance to take measurements to find out more about the animals."
The seal with the transmitter
The seal was also given a flipper tag with a unique identity number so scientists can identify her if she's spotted in another part of the world.
And Callum got to glue on the transmitter.
"It went really well," he said. "And as soon as the device gets wet we'll be able to follow the seal's every move for the next year."
You can watch Serious Ocean on CBBC from Wednesday 9 July 2008.