Full length of a gecko (?)

It's an Oriental Garden lizard. It can change colour, but not as fast as chameleons. :) The male has a red throat during mating season. This lizard had resulted in the extinction of our native green-crested lizard.

why, what happened ? Did this lizard eat the green one ? Does it bite people ?

Due to competition for their common prey. I think the green crested lizard looks nicer.