4 ms·
Traits evolve under pressure that is local to an environment and the interactions between species that inhabit it. If there were no predators of this fish that
by tsieling 14y ago
Traits evolve under pressure that is local to an environment and the interactions between species that inhabit it. If there were no predators of this fish that used echolocation or another method, then this trait is sufficient to survive and thrive. Evolution is haphazard and almost completely circumstantial, so the shortest answer is, because it didn't have to.