These streets are so narrow man. So how long left we got in this road? Six miles.

Don't kill me, please. I'm new. I'm a Nigerian in Costa Rica.

That calm tentative driver is me. Ioa Kimwleri. And this is it's a dog's life.

Over the next hour on the BBC World Service, we're going to explore the ancient bond between humans and dogs

which takes us around the world from Afghanistan all the way to Siberia but first

Costa Rica.

Oh my gosh, you've got some pond trees in the distance here, you've got these mountains, rich vegetation just spinning from the sides of the roads as you're climbing up.

I haven't quite seen any dogs yet.

Oh, oh, oh, there we go, there's one on the left.

A white dog, black spots.

There are so many street dogs here you just can't avoid them.

Ah! Fourth dog! Four stray and this guy's just jamming on the street.

Most stray dogs in Costa Rica know how to cross the street.

They will look both ways to see if a car is coming and then they'll pass.

Translator Daniela and I are on our way to an extraordinary home for hundreds of rescued street dogs.

Territory of Des Aguattes, land of the moths.

Five, six.

You've seen a pack of dogs, three, they're bossing the area.

People and dogs are just walking side by side.

Whatever your views are on dogs, it's hard to deny that there is something unique and

special about our relationship with them.

There's only a few animals over the last 15,000 years of prehistory that have

...