This is the moment a pet pit bull attacked a monitor lizard climbing a tree on his owner's property.

Footage shows the dog named Isa dragging the giant lizard down from the mango tree in Nonthaburi province, Thailand on November 18.

Owner Aun Lampo said: 'The monitor lizard lives in my garden's pond. My dog and the big lizard know each other.

‘But when sees the monitor lizard entering our compound, she gets very protective.'

The dog wagged her tail and bit the lizard down to make it leave.'

Aun added: ‘She's a very helpful dog. She guards us well so we always feel safe.'

Asian water monitor lizards normally live in canals, swamps, sewers and ponds in cities in Thailand. They feed on fish, snakes, frogs and scraps of food left by humans.

The reptiles are aggressive when threatened and have a mildly venomous bite which sometimes carries harmful bacteria. The Godzilla-like reptiles are also a protected species in the country so their population thrives.