"Snapping turtles are... we call them our garbage cans. They're bottomless pits," says Mike Hopcraft, who runs the reptile education and rescue organization The Reptile Guy.
Hopcraft says the runaway reptile was probably bought as a pet and abandoned at Mill Lake in Abbotsford, where it has been spotted several times.
The lake is home to a population of western painted turtles, an endangered species.
"A baby painted turtle would be a meal for a snapping turtle of this size," said Hopcraft. "It would probably be able to eat it in one or two bites and it'd be gone."
Hopcraft says the snapping turtle could threaten many other B.C. creatures in addition to the endangered painted turtles, and its discovery highlights the problems caused by invasive species.
"Any endangered frog or turtle that gets in front of that thing, it's going to get it," said Hopcraft.
Hopcraft says the snapping turtle needs to be removed from the lake, but if people see it they should be careful how they handle it.
"I don't recommend people try to grab the thing with their hands," said Hopcraft.
"They can be picked up by their tails safely without it being able to bite you, but as soon as you get it from the side of the shell they can actually snap their neck back and bite."
Anyone who spots the turtle can also contact Hopcraft or a conservation officer.
Snapping turtles are about 30 centimetres long and brown.