Number (with SD) of ramming and biting attempts in the four fish A and two fish B assays, for Sierra de El Abra (Pachón and Tinaja), Sierra de Guatemala (Escondido, Caballo Moro, Molino, and Vásquez) cave fish and surface fish (Choy and Rascón). With the exception of Escondido cave, Sierra de Guatemala cave fish were significantly more aggressive than Sierra de El Abra cave fish. In several comparison, Sierra de Guatemala cave populations were as aggressive and not significantly different than some of the surface fish. Tables below graphs show significance levels. Notice that Pachón, Tinaja and Escondido are significantly less aggressive than all of the rest.