Noun
birth defect characterized by the presence of more than the normal number of fingers or toes
Source: WordNetX-ray of the left hand of a ten-year-old boy with polydactyly Established traits are not immutable; traits that have high fitness in one environmental context may be much less fit if environmental conditions change. Source: Internet
Some breeds of cats are prone to polydactyly (extra toes and claws). Source: Internet