A dog-sized spider has been found in the South American rainforest.

The arachnid – which has two-inch venomous fangs and had grown to around the size of a puppy – was found by shocked Scientist Piotr Naskrecki in the undergrowth.

The spider was identified as a South American Goliath Bird-eater – the largest in the world – with a maximum leg span of around a foot, reports The Mirror newspaper.

Piotr said: “I couldn’t quite understand what I was seeing.”

Contrary to its moniker, the creature is said to feast on rodents, frogs and toads, as well as snakes and lizards.