A dog owner was given the shock of her life when her beloved golden retriever gave birth to a green puppy.

Three-year-old Rio gave birth last week to a litter of nine puppies - but when one came out mint green Louise Sutherland was speechless.

The extremely rare occurrence is thought to have only happened three times before in the world.

Three-year-old Rio gave birth last week to a litter of nine puppies - but when one came out mint green Louise Sutherland was speechless

The extremely rare occurrence is thought to have only happened three times before in the world

It is caused by a bile pigment called billiverdin that is found in the placenta of dogs.

The substance can stain the puppy's coat when it mixes with the mother's amniotic fluid - the liquid that protects and nourishes the pup.

Mrs Sutherland from Golspie in the Highlands has now named the pup Forest in recognition of her unusual shade.

She said: 'The first pup was stuck, so myself and my daughter Claire managed to free him and pull him out safely.

The substance can stain the puppy's coat when it mixes with the mother's amniotic fluid - the liquid that protects and nourishes the pup. Pictured, Rio with her puppies (left) and Mrs Sutherland (right) with the brood shortly after the birth

She said: 'It was all hands on deck but then as the puppies started to arrive, we noticed that one of the puppies had green fur! We couldn't believe it.

'When we checked it out later we found out it is very unusual and to do with the placenta. The colour has faded quite a bit already and will be gone soon, I'm told. We've named him Forest.'

A couple from Lancashire, whose chocolate Labrador gave birth to a green puppy in February this year found only two other similar cases, including one in Spain.

Mrs Sutherland said: 'Rio had a total of seven boys and one girl and they are all great and growing like mushrooms.

'This is her second litter but the first was much more normal - a five-hour labour and five pups, two girls and three boys. But this will be her last!'

Mr Sutherland has managed to find good homes for all the puppies but is planning to keep Forest for herself.