Moronic tourist under investigation after dumping water on ‘historically significant’ ancient cave paintings for social media

He’s got the brains of a caveman.

A dim-witted tourist dumped water on ancient cave paintings to snap better photos for social media — and is now under investigation after posting the shots of the damaged historic art, according to cops.

The unidentified 39-year-old man from Los Villares, Spain, wanted “clearer” and brighter images of the priceless works, which were sketched in the country’s Sierra Sur de Jaén mountain range thousands of years ago, local law enforcement said.

To get the perfect shot, he tossed the liquid on the precious paintings — part of a site that’s been deemed “historically significant” by the country’s heritage group — and later posted the wet images on Facebook,  according to Guardia Civil’s nature protection force.

The ancient art is made on limestone, which contains water-soluble salts that dissolve in liquid, leaving a crust that causes “irreparable damage” to the paintings, officials said, according to The Daily Beast.

The aqua-tossing twit is now in hot water as the agency investigates him.

It wasn’t immediately clear when the vandalism took place or what the specific art depicted, but some cave art from the area shows faded stick-figure like designs smudged in black.

Some of the paintings in the breathtaking mountain range are  believed to be more 6,000 years old.