A BOA constrictor is on the loose at a North Yorkshire beauty spot, wildlife experts have confirmed.
The six-foot snake was spotted and photographed by a walker at Swinsty reservoir near Harrogate and identified by the Yorkshire Naturalists Union.
Visitors to the area are being warned to be on their guard and keep their dogs on leads.
Boas kill by asphyxiation, wrapping their bodies around their prey in a deadly squeeze.
They are stealthy hunters, feeding on a variety of small animals including mammals, birds and amphibians.
Geoff Lomas, site manager for Yorkshire Water, which owns the reservoir, said: “Clearly there is some concern in that we have a snake, of which we know very little about, including when it last ate, on the loose in a vast woodland area which is very popular with visitors from across the region.
“Whilst a boa constrictor is unlikely to pose a risk to humans, a lot of people walk their dogs around the site and clearly dogs could be at a small risk from such a predator.
“With this in mind, we’re saying to people, please do come to the site, but please be sensible and exercise caution when out and about, ensuring all dogs are kept on a lead.”
The snake is likely to be an escaped or abandoned pet. The non-venomous species is native to the Americas but can be legally kept in the UK.
“Over the years, we’ve discovered a number of escaped or unwanted exotic pets at our recreational sites across the region, such as terrapins and koi carp, but never an exotic snake more commonly found in the jungles of South America,” said Mr Lomas.
Ed Ryder, from Otley, who raised the alarm after spotting the snake at around 6pm last Saturday while walking with his girlfriend, said: “I’m not fond of snakes at all, I didn’t even like my grandma’s snake draught excluder.
“I enjoy running around Swinsty, and I have been wondering how to get my speed up – I don’t have to worry now.”
Boas can grow up to 12 feet in size and are recognisable by their brown colour and distinctive brown or reddish brown patterns.
As cold-blooded reptiles, they need warmth to sustain them and are unlikely to survive for long in the UK climate.
Anyone who spots the boa is urged not to approach it and to call the RSPCA’s 24-hour advice line on 0300 1234 999.