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A gynandromoprh cardinal

A gynandromorph is an animal that is part male and part female. The distinction is usually clearly demarcated. In the cardinal, the difference between the gendered body parts are especially clear because of sexual dimorphism - the difference in appearance between the males and females of the same species. Male cardinals have evolved to be a flashy red, likely in order to attract the attention of a mate, while the female cardinal is under less pressure to impress. 

The more interesting question, of course, is how the bird became a gynandromorph in the first place. Gynandromorphy is well understood in species like Drosophila, where there is only one sex chromosome, so the difference between a male and a female cell is the presence or absence of a second X chromosome. During development, the loss of a chromosome and the subsequent proliferation of the different daughter cells would produce a gyandromorph adult. In the case of birds, which have two sex chromosomes (just like humans), the science is more complicated, and so we aren’t exactly sure of the origin of this cardinal. However, gynandromorph cardinals aren’t unprecedented, and this article from LiveScience about another specimen hazards a guess as to the biology behind this phenomenon.

Quick Links

• Gyanandromorphs - Wikipedia
• Sexual dimorphism - Wikipedia