What sets Calico cats apart is their tri-color coat. Calico cats have at least three colors in their fur, which at their most basic are white, orange, and black. Calico cats are predominantly female because their coloring is related to the X chromosome.
Calico cats are thought to bring good luck in Japan. In the past, Japanese sailors would travel with Calicos onboard their ships for protection. In the U.S. and U.K., male Calico cats have been thought to be especially lucky because they are so rare.