Police found a seal abandoned in a field in St Helens.
Officers were called to an area in Newton-le-Willows on Monday morning after a startled dog walker discovered the animal.
Police have contained the seal in the field but are yet to capture it.
They are not revealing the precise location fearing it will lead to onlookers flooding into the area.
A force spokeswoman said representatives from the British Diver Marine Life Rescue Service are making their way to the scene.
The spokeswoman added: “Seals are powerful animals and potentially dangerous.
“Police are advising the public to stay away from the area.”