Side-blotched lizard

Complicated taxonomy, even more complicated reproductive ecology. Read about it here, if you're ready for a "five-gender" system with two different types of females employing either K- or r-selection strategy, three types of males whose genetically determined mating strategies resemble a high-stakes game of rock-paper-scissors, and relative abundances of each gender type fluctuating on either a two- or four-year cycle.

The old argument of design in nature, as given by Paley, which formerly seemed to me so conclusive, fails, now that the law of natural selection has been discovered.

—Charles Darwin