Most sponges are flat, but tool-using dolphins select conical ones that will not fall off their snouts. The majority of dolphin “spongers” are females.
Krützen also has an idea about why males do not like using sponges. “Males are more interested in forming alliances with other males than sponging,” he says. “They have a different social life than females, and this might restrict them to invest too much time in sponging, which is quite a solitary activity.”
I am sure many male mammals would concur.