This is the dramatic moment monitor lizards were spotted grappling next to a canal in Thailand.

The beasts were spotted by a local who watched the intense standoff near the waterway in Kamphaeng Phet on July 16.

Footage shows the reptiles locked in a brutal embrace, gripping each other's forelimbs before toppling into the murky water.

The powerful creatures rolled and thrashed, half-submerged, sending dirty water splashing in every direction.

Monitor lizards engage in fights for several reasons. They are territorial animals, and males often fight to establish dominance and claim their territory.

They also fight during mating season to compete for females. These fights help determine which male is stronger and more suitable for mating.