Thirteen-month-old Lamo is so sure he is a canine he fetches sticks and balls, wears a collar and a lead, jumps up on his hind legs and tries to bark.
Lamo does not even recognise his own kind - preferring to chase rabbits instead.
Owner Jennifer Jones, 45, who runs Rockfield Animal Rescue in Wentnor, Shrops, took Lamo in when he was run over last February.
She fed Lamo milk and brought him up with her three dogs - a Staffordshire Bull Terrier called Wallace, a Jack Russell called Judy and a Labrador called Poppy.
She said: "Lamo was given to me as a terrified little lamb and we have no idea where he came from.
"There's a farm nearby but the farmer said it couldn't be his.
"I raised him with my three dogs so now he thinks one of them.
"He really is wonderful, he follows us around everywhere and is always under our feet.
"He doesn't care about the other sheep, he prefers humans. He's always trying to get our attention and is constantly getting up to mischief."
Jennifer also takes Lamo round to her friends' houses to mow their lawn by chewing the grass and puts him on a lead to take him for walks at the weekend.
Incredibly, the sheep also enjoys going for a quick doggy-paddle in the local lake.
She added: "He gets really excited when we take him out in the van for a walk down the country lanes.
"He wriggles around and starts screwing his nose up
"When we swing open the back doors he's standing there panting and looking really pleased with himself.
"He loves a little swim now and again too - it's quite amazing to see him dive in for a quick dip."
Vet David Howell said: "Sheep are more intelligent than some people think and they are very capable of learned behaviour.
"Most sheep do revert to their natural characteristics if they are not brought up in their natural surroundings but clearly Lamo prefers life as a dog."
As long as he's happy... I guess.
