DID you hear the one about a giant lizard in a layby?

It may sound like the set-up for a joke, but the story of a five-foot long iguana found near a main road in the Borders is more of a mystery than a comedy.

The large reptile was discovered by a council worker next to the A702 in Peeblesshire.

The find happened on Tuesday near Broughton Primary School where the iguana, which is native to South and Central America, was struggling in the low temperature.

No one knows how he got there, but it is thought that he may have perished if he had been left in the open countryside for much longer.

The plant-eating species must be kept in temperatures of 26C-35C – far warmer than the increasingly autumnal conditions southern Scotland can currently provide.

The Scottish SPCA is now appealing for his owner to come forward after taking the cold-blooded creature into its care.

Dubbed Iggy, the green iguana is described as “very large” and is recovering from his outdoor adventure in a heated home.

The charity was called to the school after the unusual visitor was taken inside to warm up.

Animal Rescue Officer Dawn-Vale Lowdon, who collected Iggy, said: “We were alerted to the lizard after it was discovered by a vigilant member of the public. Despite having a few bumps, he was alright once he had been warmed up.

“He’s now being cared for at our centre in Lanarkshire where he has been named Iggy. If no-one comes forward for him we’ll keep him in our care until we can find him a suitable forever home.”

It is legal to keep the scaled species as a pet in Scotland, but the lizards are not recommended for anyone who has not cared for reptiles before.

As well as heat and a suitable diet, they also require a steady supply of both UVA and UVB light to help their bodies absorb the nutrients they need.

Specialist dealers can charge hundreds for the creature, with a suitable vivarium and equipment pushing costs up further.

And, while Iggy measures more than 5ft long, his species can grow even longer, reaching up to 7ft in some cases.

Commenting, Fiona Henderson, chief inspector at the Scottish SPCA, said: “Green iguanas are kept commonly as pets. They require a lot of care as UV lights, heating and a big vivarium is needed to keep them comfortable.

“Iggy’s tail alone is at least 3ft so he’s very large, although he is now an adult so shouldn’t grow any more.”

Anyone concerned about the welfare of an animal should contact the charity’s animal helpline on 03000 999 999.