'Snappy' has been feeding off the wildlife in the country park

The snapping turtle, which is native to America, was first spotted by head warden Dennis Manning 17 years ago.

Then it measured 10in (25cm), but after feeding off ducks and moor-hens, has grown to 2ft (60cm) and 20lb (9kg).

It is now being moved from Caldicot, Monmouthshire, to the Tortoise Trust rescue sanctuary in west Wales.

The freshwater turtle, which has been named Snappy by wardens, was thought to have been released at the park by owners who did not want it.

Known as an aggressive species, it has a long spiky tail, claws and a sharp beak and "will eat anything it can catch".

It will be under the water like a submarine and when it spots something it wants to eat, it will shoot its neck out really fast and drag it under

Caldicot Country Park head warden Dennis Manning

The turtle is usually found in the wild in the Americas, spreading from Canada to Florida and as far south as Ecuador.

"It is like a submarine killer," said Mr Manning. "It will be under the water like a submarine and when it spots something it wants to eat, it will shoot its neck out really fast and drag it under.

"It doesn't have teeth, just a very sharp beak. I had been wondering why our moor-hen and duck population had been on the decrease," he laughed.

Mr Manning first saw the creature when it had been dug up in a mechanical digger.

"He was excavated by the digger and so we put him in a bucket and put him back," he said.

Snake survey

"Back then it was only small and we didn't really know what to do with it.

"I next saw him about 10 years ago and he was quite a lot larger than the first time. He was walking from the pond."

Snappy was finally caught by another park warden, Phil Marshall, as he carried out a survey of snakes in the park.

"He saw him walking along and quickly picked him up and put him in his wheelbarrow," said Mr Manning.

It was caught making its way to a pond on the park

"He must be about 30 years old now," said Mr Manning.

"We have had a lot of terrapins released here which we can re-home quite easily but he's a bit too big for that and he's quite dangerous too.

"He is a ferocious eater and could take your finger off if he bit you.

"We are not sure if he is a common snapper turtle or an alligator snapper. Either way, he isn't native to this country and nor to our wildlife.

"It's just a shame people don't think about what they are doing when they release animals like this in the wild."

It is not the first strange creature spotted by the wardens at the park - a boa constrictor snake was discovered there 10 years ago but was run over before it could be captured.