Side-blotched lizards have an odd way of picking mates. Rocks or Jocks on this Moment of Science.

A recent study on the mating preferences of side-blotched lizards was done by Ryan Calsbeek of UCLA and Barry Sinervo of UC Santa Cruz. The females of these little critters clearly prefer to mate with the biggest, most dominant males of the species.

It's already known that what rocks you live on is very important to a side- blotched lizard. They need the right amount of sun and shade. What would happen if the rocks were taken from the jocks and given to smaller lizards--the geeks? Would chicks miss rocks or stick with jocks?

Well, when Sinervo and Calsbeek took away rocks, the lizard chicks lost their socks. Now the rocks were given to geeks. Jocks had no rocks, geeks had lots! Lizard chicks went off their blocks!

Most females left the dominant males and mated with the smaller lizards instead. It suggests that the females were with the big males because the big males were able to score the best living environment, not just because they were big.