This may be ad hoc, but I could see warmer temps being a signal for environmental instability, therefore more males equals more genetic variability (more alligators), giving the population a better chance of adapting.

Cooler temps, creating more females, so as to "lock in" certain traits into the population.

IMO, systems seem to fluctuate between "searching" patterns and "chasing" patterns; robustness and efficiency, community and hierarchy, public square and tower, or as the alchemists said: solve et coagula.

You see this too in society: certain segments of society seem to follow either r or k patterns. Poorer people have more children, less neoteny shorter lives, etc.