Rock-paper-scissors is a fun game that is played by people of all ages and nationalities. But there is also a species of lizards that plays this game, albeit in a rather strange way.
Male common side-blotched lizards, also known as Uta stansburiana, have a mating strategy based on the game, where the chances of “winning” is equal and one type has an advantage over another type while being disadvantaged against another type. The males come in three types, differing in the colour of their necks: orange, blue and yellow.
- Orange-throated males are the strongest but do not like to form a bond with the female (i.e. do not want a relationship). They can easily win over a fight against the blue-throated males to win the female, but yellow-throated males can sneak in and win over the female instead. Orange beats blue but loses against yellow.
- Blue-throated males are middle-sized but do form strong bonds with females. They lose in a fight against orange-throated males, but can easily defend against yellow-throated males as they are always with their female. Blue beats yellow but loses against orange.
- Yellow-throated males are smallest but can mimic females, letting them approach females near orange-throated males. They mate with the females while the orange-throated male is distracted, but this strategy does not work with blue-throated males as they have stronger bonds with the females. Yellow beats orange but loses against blue.
Interestingly, although the proportion of the three types average out to be similar over the long run (much like the probability of a person playing a certain hand), in the short term the preferred strategy tends to fluctuate. For example, orange-throated males may strive with their masculine strength for four or five years, but then the trend will slowly switch to yellow-throated males and their mimicking, female-stealing strategy. After another four or five years, blue-throated males will make a comeback as they win over females with their strong bonding.