[bobim]

This is an interesting take, along the line of elephants who need a huge brain mainly to actuate their trunk.

[calmbonsai]

Akin to bottle-nose dolphins and orcas with sound. They have, easily, the most signal-processing neurons of ANY species on the planet.

And, fwiw, their encephalization quotient is just behind one species--us.

Since they're aquatic mammals (given the requisite mass for thermoregulation), that severely under-represents their effective brain/body-mass ratio too.