Around 30 years ago an unlikely craze swept the globe.

The stories of four crime-fighting reptiles captured the hearts of children everywhere and soon the Teenage Mutant Ninja Turtles were big business.

But some parents, eager to please their little ones, took it one step further and bought terrapins in honour of the cartoon characters.

Norwich Evening News: Terrapin's have been spotted throughout the river Wensum in Norwich.Terrapin's have been spotted throughout the river Wensum in Norwich. (Image: PA Archive/PA Images)

But terrapins don't make for the cuddliest of pets. And now Michelangelo, Donatello, Raphael and Leonardo have made a come back - in the Wensum.

Terrapins have been spotted up and down the river and experts believe they have thrived after being dumped as unwanted pets.

Jake Horne, 29 and his wife Jessica from NR3 spotted one huge specimen from their kayak last weekend.

Norwich Evening News: Jake and Jessica Horne live in NR3 and try to get out on the river a couple of times each month.Jake and Jessica Horne live in NR3 and try to get out on the river a couple of times each month. (Image: Jake Horne)

Jake said: “We were heading upstream towards Hellesdon Mill.

“We were paddling along, chatting and enjoying the lovely spring sunshine.

“I happened to just look around and I saw the turtle, I couldn’t believe it.”

Jake and Jessica paddled over to where the turtle was in order to get a closer look.

Norwich Evening News: The Terrapin was basking in the sun not far from Gibraltar Gardens.The Terrapin was basking in the sun not far from Gibraltar Gardens. (Image: Jake Horne)

He said: “At first I was unsure if it was real as there are some landmarks along that stretch of river that are fake, but then it moved.

“We kept our distance as we didn’t want to startle it but it really was an actual turtle basking in the sun.”

Norwich Evening News: Jake and Jessica Horne were surprised to see the non-native turtle basking in the Norfolk sunshine.Jake and Jessica Horne were surprised to see the non-native turtle basking in the Norfolk sunshine. (Image: Jake Horne)

Jake said: “Before this, the strangest thing I had seen was crayfish, they were non-native ones that originate from America.”

He added that he was excited to have seen it the terrapin but he doesn’t want people to go looking for it.

And Scott Birch also found a hero in a half shell while fishing in Costessey last year.

He said: “I got a bite and I reeled in what I thought was a rock.

Norwich Evening News: Scott Birch found a Terrapin at Costessey Mill while fishing last year.Scott Birch found a Terrapin at Costessey Mill while fishing last year. (Image: Scott Birch)

“It turned out to be a red-eared terrapin which is a non-native species.

“They are not supposed to be in UK river and are clearly from Ninja Turtle craze.”

Norwich Evening News: At first Scott Birch thought he was reeling in a rock, it turned out to be a non-native terrapin.At first Scott Birch thought he was reeling in a rock, it turned out to be a non-native terrapin. (Image: Scott Birch)

Kevin Murphy from Norfolk Wildlife Rescue has seen many terrapins along the river Wensum when kayaking.

He said: “They are likely unwanted pets, there was a huge influx in demand after a Ninja Turtles film at the cinema.

Norwich Evening News: Kevin Murphy, Norfolk Wildlife Rescue urges people to leave spawn when it's in the wildlife, unless it's in danger.Kevin Murphy, Norfolk Wildlife Rescue urges people to leave spawn when it's in the wildlife, unless it's in danger. (Image: Kevin Murphy)

“These terrapins grow to a huge size and most folk fail to fully accommodate them.”

Kevin advised people not to buy them as pets as they grow to the size of a dinner plate.

Fact file: What is a terrapin?

Terrapins are a type of hard-shelled small turtle that live in fresh water and ponds.

The most common species being red-eared sliders, yellow-bellied sliders and Cumberland sliders.

The lifespan of a terrapin is around 30 years.

Females can grow up to 25cm and males 21cm.

Terrapins eat freshwater fish and invertebrates.

But experts say ownership is not something that should be rushed into as they require lots of care and equipment to keep them healthy.

They should not be petted and are especially fragile when they are young.

Abandoning terrapins in UK waters is illegal because can damage the local ecosystem and can cause the released animal to suffer in the new conditions.