Let's start out by watching this video. Warning: it's a tear-jerker!
It's all down to their scent
That video makes it clear that dogs remember their owners, no matter how long they've been gone for - whether it's weeks, months or even years. And it could all be down to their scent. Dogs possess 300 million (yes, million!) olfactory receptors in their nose. We only have 6 - so it's quite a significant difference! But it doesn't stop there. The part of a pup's brain which analyses smells is 40 times greater than ours, proportionally. Dogs also have an olfactory memory, which means they're capable of remembering scents a long, long time after being exposed to them. This means that even if you were to look completely different, your pup would still be able to recognise you.
However, facial recognition plays a part too
Even though a dog's sense of smell is incredibly strong, they'll still recognise you by looks, too! A study by the University of Padua concluded that dogs 'rely on their site to discern their masters'. So, a combination of sight and smell will make your pooch go crazy over you every time they're reunited. However, a blind dog could still recognise their family, purely through smell - pretty amazing, right?
But most of all, it's love!
Never mind sight and smell, we think that the most important role here is love. Watching a dog being reunited with their owner always brings a tear to our eyes - the love of a dog is just unbeatable, don't you think?