The rodents, twice the size of common types, are plaguing an estate in Bradford, West Yorks, often appearing in kitchens and lounges.
It is feared some could be “super rats” from South America.
Pictured above is a monster 2½ft rat killed on the estate.
… “At night you can hear them chasing each other in the loft. They sound like drag racing cars as they screech across the rafters.”
Last night experts called the shot rat “extraordinary” and said the colony was worth investigating.
Laura Drake, of the Mammal Society, speculated it could be a coypu – a South American rodent often referred to as a “giant rat”.
Coypus were thought to have been eradicated in Britain in a cull 20 years ago. But Laura said it was “not impossible” there had been survivors.
Yorkshire Rat Club president Colin Arundel said rodents, like humans, could simply be getting bigger as food becomes more and more available.
The RSPCA said: “The most likely answer is the shot rat was from a non-indigenous species that was in captivity and got out.”