On day 4 after the birth, Hardy observed superfemale
21 near the birth site as five of her newborns crawled around.
In this experiment we investigated whether supermale and superfemale
faces, with exaggerated sex-typical traits, are preferred to average male and female faces, respectively.
This creates the hypothesis that the system of sex determination in sturgeons is genetic and not environmental, which is backed up by gynogenesis experiments suggesting sex ratios in conformity with the ZW system where gynogenesis may produce ZZ males, WW superfemales
, and ZW females.
The project ended when the researchers realized that their superfemales
produced only sons.
Inducing these turtles to become "superfemales
" could prove harmful, she worries, if they divert unhealthy amounts of energy into egg production.