Four beaver families have arrived in the UK, as part of a plan to bring the creatures back to Scotland for the first time in hundreds of years.
Experts tracked the animals in Norway for two months before capturing the beaver parents and their young.
The families will now spend six months on their own, being looked after in something called quarantine.
They will then be released into the wild in spring 2009, as part of a five-year trial.
Animals are kept in quarantine to give experts time to study them, and make sure they aren't carrying any diseases that they could pass on to other wild animals.
The beaver families are made up of one adult male, one adult female and between one to three young beavers, called kits.
Beaver fact file
Their noses and ears close up so they can survive underwater for a long time
They have big tails which act as 'rudders' to help them swim
Their teeth never stop growing!
They have to permanently chew on wood to stop their teeth getting too long
A team of wildlife experts had to watch the creatures in the wild for a long time to make sure they captured the whole families, and didn't leave any family members behind.
The creatures mainly come out at night, so they had to be tracked using boats, and caught in the dark.
Beavers were wiped out in Britain back in the 16th Century, by hunters who trapped them to sell their fur.
Wildlife experts say bringing them back will be good for the environment, because they create wetland environments for other animals to live in.
But not everyone's happy about the idea.
Some people in the fishing industry say the beavers' dams could affect fish numbers, by stopping them moving around the rivers and breeding.