What is a characteristic of tortoiseshell cats?

Tortoiseshell cats are characterized by their distinctive and varied coat color patterns, which typically include a mix of black, orange, and cream colors. This unique combination is a result of the specific genetics associated with coat color in cats, particularly the X chromosome, where the genes for black and orange fur are located. Tortoiseshell cats often display a mottled or patchy appearance, showcasing the blending of these colors in various ways across their fur.

The other options do not accurately describe tortoiseshell cats; they are not typically male since the majority of tortoiseshell cats are female due to the genetics of the coloring. Additionally, tortoiseshell coats can appear in mixed-breed cats as well as purebred ones, so stating that they are always purebred isn't correct. Lastly, being characterized by a single solid color contradicts the very definition of a tortoiseshell pattern, which is defined by its diverse coloration. Thus, the attribute of having a mix of colors is what truly defines tortoiseshell cats.