Marty’s photo of the day #5141: You are looking at a Christmas tree marine iguana (also known as Española marine iguana). These lizards are a subspecies found only on Española island. While most marine iguanas are black to absorb sun heat, the males on Española turn brilliant red and green to attract mates—an adaption believed to be the result of fewer prime breeding sites on the island.

(Photographed in the Galapagos Islands.)