Tom Thumb, the world's smallest dog?

He is a third of the size of an average guinea pig, and weighs in at just a few ounces - but this tiny puppy could be a big deal when it comes to world records.

The miniscule chihuahua-Jack Russell cross - appropriately named Tom Thumb by its owners - is a serious contender for the title of being the smallest dog on the planet.

Little Tom was born just three weeks ago as part of a surprise litter to mum Spice, a chihuahua. More + pictures...

See also:

1. Chilli: the biggest cow in the world?
2. Looking for a new kind of pet? How about a mini pig?
3. Meet the world's cutest mini horse!!!