this is a cast of a skeleton of a small female sperm well I guess the thing that catches the attention is the lower jaw lined with these curved backwards-facing teeth but weirdly it seems that actually the predatory weapon of a sperm whale is up here this is where the bulk of the head sits and it is immense it could make up as much as a third of the animal's body length almost all of this is filled with sperma Ceti that waxy oily liquid the sounds that the sperm whale generates are bizarrely created at the front of the nose traveled back through the stoma Ceti until they hit this portion of the skull which is shaped like a satellite dish a parabola and it focuses and intensifies the sounds as they pass back through the sperma Ceti and then out of this end of the animal this beam of sound bounces off objects in the water by listening to the echos sperm whales build up a three-dimensional picture of their surroundings using this system they can hunt in total darkness over a thousand meters underwater to feel the force of these sounds for myself I'm heading back out to see we have a mother and a car approaching from this side traveling very quickly and three animals traveling from this looks like their pods are going to converge right in front of us it's possible this could be exactly what we've been waiting for if it's a family group there's likely to be a lot of communication this is my chance to feel the power of sperm whales so now I've dropped right into the middle of a group of socializing sperm whales and the sound is overwhelming the largest males can generate 230 decibels far louder than a jet plane taking off the whales seem to be scanning me firing sonar at my body and visualizing its shape by listening to the echoes it's highly directional as the barrel of the whales head turns towards me I can feel the sound resonating through my whole body and she's giving me a good eyeballing the biggest sperm whales can be 20 meters long and four times heavier than a fire engine physically I have little in common with this super giant yet I feel closer to it than any of the others with both creatures with close family bonds a real sense of curiosity and a desire to communicate