Ken O'Sullivan

Now, sperm whales are the absolute grand masters of this because they're the largest heads of any animal that ever lived.

the skull has evolved in a shape that is optimal for pushing out these pulses and it's filmed with a waxy liquid called spermaceti so a few years ago I was chatting with the great um BBC cameraman Doug Allen sadly passed away recently and you know I was asking his advice for swimming with sperm whales because I was hoping to do it in Ireland and he told me he'd been in the water with one and it was as it was scanning him it felt like his chest was going to collapse because

to 230 decibels of sound, right?

And so if we think a jet engine taking off is 150, a rocket is 190, they can do 230 decibels.

And so they've evolved incredibly sophisticated ways to use sound.

And it's no surprise then that we see they also have the largest brain of any animal ever to have lived.

No surprise that they have sophisticated communications language between them.

Well, what you might have heard towards the end of the clip there, we sent that to an ocean acoustics expert, Dr. Joanne O'Brien in Ireland, and she confirmed, yeah, that's sperm whales, but she also confirmed the noise at the end, which we thought was our boat slapping off the water, was actually the sound of seismic surveying 400 kilometres to the south on the Porcupine Bank.

So this is where they use air guns to blast at the seabed to build a profile to see if it's likely there are deposits of oil and gas

Clearly, those kinds of sounds obviously can mask communications between animals.

I think of greater concern is probably in recent years, there is military sonar has been developed to give a huge sonic capacity, huge volume, and NATO conduct exercises twice a year west of Scotland, which of course is north of Ireland, Operation Warrior, Joint Warrior, Strike Warrior.

It's an anti-submarine warfare exercise.

And they've been doing this since the Second World War because obviously there are serious threats from submarine enemy, military, etc.

But the military sonar, which they're using to

distances to see what's there.

Of course, it's causing serious trouble to a lot of particularly deep diving whales.

So it does two things.

First, of course, it means they can't hear.

But second, it's so loud, it deafens them.

And also it scares them to the point that they might rise from 2000 meters depth of water far too quickly.