At a stately museum in Mexico City, priceless paintings by Frida Kahlo and Diego Rivera share pride of place with an unruly pack of hairless black dogs: Mexico's prized xoloitzcuintle.

The dogs who reside on the leafy grounds of the Museo Dolores Olmedo are the direct descendants of ones that belonged to Kahlo and Rivera, whose searingly intimate portraits (her) and sprawling murals (him) made them the towering power couple of the 20th-century Mexican art.

Kahlo and Rivera were proud of their Mexican heritage, which made the xoloitzcuintle an obvious choice for the family dog.

They even put their dogs in their paintings - some of them now on display at the museum where their great-great-grandpuppies reside.

"Xolos," as they are known for short, are a quintessentially Mexican dog.

The ancient species goes back 7,000 years and was first domesticated around 5,500 years ago. 

AFP