The Scottish SPCA was alerted on Thursday, July 24 after a cyclist discovered the royal python next to the A721 near Carstairs.
The snake is now in the care of the Scottish SPCA's Lanarkshire Animal Rescue and Rehoming Centre in Hamilton, where he has been named Roy after the cyclist who found him.
Animal Rescue Officer Gavin Law said, "Roy was spotted on the grass beside the lay-by.
"He may be a stray but I think it's more likely he was abandoned as there aren't many houses nearby.
"It's possible someone pulled into the lay-by, let him out and then drove away.
"When I rescued Roy he was very cold and lifeless but he soon warmed up due to the heat inside my van and began moving again.
"We'd urge anyone who knows who may have owned Roy to contact us.
"If we're unable to return Roy home we'll look after him until we can find him an experienced new owner."
Abandoning an animal is an offence under the Animal Health and Welfare
(Scotland) Act 2006 and anyone found guilty of doing so can expect to be banned from keeping animals for a fixed period or life.
Anyone with information is being urged to contact the Scottish SPCA Animal Helpline on 03000 999 999.