The female boa could have chosen any number of male partners (and had successfully in the past) but on these occasions she reproduced asexually, creating 22 female babies with WW sex-chromosomes.
Aquela femia tiña para elixir varios compañeiros machos (e reproducírase con éxito con eles no pasado) pero naquela ocasión reproduciuse asexualmente, orixinando 22 crías femias con cromosomas WW.