'One in 3000': Meet Unicorn, the rare male calico kitten

A cat rescue in the US has taken in a very special find, the first of its kind that founder Davida Dupont has seen.

The cat is a male calico and while he's not quite one in a million, he is one in three thousand, according to the Cornell College of Veterinary Medicine – so rare enough.

That's why foster-focused rescue NoCo Kitties in Colarado gave him an appropriate name: Unicorn.

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Born in a shed, Unicorn was turned over to the Weld County Human Society and placed into the care of NoCo Kitties.

NoCo Kitties volunteer Alli Magish took in Unicorn, his mum Amber and four siblings, which included two calico sisters.

After suspecting Unicorn was a boy, she wanted to double check given the rare possibility.

Two vets confirmed the little kitty's gender and it was believed to be the first they'd ever seen.

"We just thought how incredibly unusual and what fun it is," Dupont told

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The reason male calico cats are so rare is because their fur colour is linked to their chromosomes, and generally only female cats carry the chromosomal combination needed for the calico pattern.

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However, approximately every one in 3000 cats born, a male cat will develop an extra chromosome and come out with the tri-coloured coat.

While 'calico' cats are not a breed, their particular colour combination and pattern is distinguished as calico cats.