A man discovered a royal python by a canal in Doncaster while walking his dog.
The three-foot-long female snake was most likely abandoned by its owner, the RSPCA said.
According to the BBC, a reptile expert said the snake would not survive in the wild.
Kim Greaves of an animal welfare charity added that the person who dumped the animal would be prosecuted if found.
Speaking to The Epworth Bells, she said: "More and more of my colleagues are faced with abandoned animals, not just snakes and reptiles, but rabbits, guinea pigs, ferrets and cats and dogs.
"It is a sign of the times, I'm afraid."
Royal pythons are non-venomous and survive on a diet of rodents.
Earlier in August, a snake owner revealed that her six-foot hungry boa constrictor was on the loose in South Yorkshire.
Corrine Swann told the Daily Mail her pet had not eaten for two weeks and was due to be fed when she escaped.
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