Wednesday, January 4, 2017

The language of sperm whales: by David Cox

Sperm whales are the biggest living things with teeth, and they seem to "talk" to each other. To decipher their messages, scientists are free-diving with them.. Sperm whales have the largest brain of any living animal. At 8,000 cubic centimetres, it is over five times the volume of ours, a comparably minute 1,300 cubic centimetres... What's more, their neurological processes are far more cemented in evolutionary history. The human brain has changed markedly over the past million years, and we have only had the big brains we do now for about 200,000 years. In contrast, the current size of the sperm whale brain has changed little from that of its cetacean ancestors, which evolved some 55 million years ago...

A decade ago, Fabrice Schnöller was an engineer working on systems for tracking sharks. Then, in 2007, he went on a sailing trip to the island of Mauritius, where something happened that would change the course of his life. As his boat approached the coast, giant towers of steam began exploding out of the water. One by one the columns closed in, until they surrounded the whole boat. Curious as to the source of this strange ocean phenomenon, Schnöller grabbed his snorkling equipment and a camera, and jumped in.

Diving down beneath the ship, Schnöller's ears were bombarded by what sounded like underwater explosions, growing louder the deeper he went. At first he feared the boat had suffered a mechanical failure. But as he circled around, he began to sense that he was not alone.

Glancing downwards, Schnöller froze. Out of the darkness, a series of giant dark monolithic shapes were heading directly towards him. It was a pod of sperm whales accelerating towards the surface.
As they approached, the sounds grew louder and louder until they penetrated his flesh like an X-ray. Schnöller felt the warm vibrations passing through his skeleton from every angle.

The whales surrounded him, staring with large, unblinking eyes. At more than 60 feet in length and weighing approximately 125,000 pounds, they dwarfed him. But rather than swallowing the helpless Schnöller in one giant gulp, the whales appeared to be deeply intrigued. After scanning him, the rhythm structure of their sounds began to change. Schnöller later realised that these were the patterns that we believe sperm whales use to communicate and send information. The whales appeared to be speaking to him.

They stayed for two hours, circling, staring and showering him with bursts of sound, before vanishing once more into the deep. Schnöller was entranced. "In France we say that you see the soul of a person through their eyes," he says. "With sperm whales you really feel a connection, which is totally different to other animals. When you dive with a big fish like a shark there's nothing at all, but when a sperm whale looks directly at you, you can feel he's thinking and analysing you, and you don't know who's weighing up who."

The whales were curious about Schnöller. "I could see instantly that all of them were very interested in my camera," he says. "One of them would take it in its mouth, and I'd have to go bring it back. That kind of extreme curiosity is something you would typically expect from only humans. But what I wanted to find out was whether their behaviour was simply curiosity, or was there something more?"

Were the whales really trying to communicate with Schnöller? To find out, in 2009 he began a new project called DareWin to understand sperm whale communication at a deeper level than ever before.
There are only 20 or so scientists in the whole world studying sperm whales, which are notoriously shy and elusive, so progress is slow. Schnöller aims to speed things up by collecting the largest-ever database of sperm whale vocalisations and behavioural videos.

His ultimate goal is to first decode the information contained within whale clicks, and then construct a new click that he could send to the whales. But this would require going where none of his peers had gone before: freediving and mingling with the whales... 

Sperm whale vocalisations have long fascinated scientists for one reason in particular. They are almost inconceivably loud. While normal human speech takes place between 60 and 65 decibels (dB), sperm whale clicks, described as such because we hear them as "tak-tak-tak", can reach as high as 235dB. In contrast, a loud rock concert is around 115dB and the sound of a jet engine is roughly 140dB. Quite simply, sperm whales are the loudest animals on the planet.

Such is the power of their clicks that whales can comfortably transmit information to others from hundreds of miles away, and even across vast oceans. A sound of 180dB is enough to cause drastic cell death in your ears, but the most powerful sperm whale clicks will not merely deafen you: they can vibrate the fragile human body to pieces. The whales have evolved these astonishingly powerful vocalisations to cope with their extraordinary lifestyle. Sperm whales range across the open ocean, but they typically gather at deep canyons, to socialise, mate and hunt food sources no other predator can reach. They dive up to 10,000ft under the ocean surface, hunting for fish and giant squid.

Some scientists believe the whales also use them to pass information between each other

A sperm whale detects its prey by sending echolocation clicks from the front of its nose and listening for the echo, which reverberates in a fatty sac beneath its mouth. This enables it to pinpoint a single squid from thousands of feet away. "Sperm whales spend most of their lives in the darkness because they hunt in a part of the ocean where light does not reach," says Fred Buyle, an underwater photographer and cameraman with DareWin. "They use these clicks as a visual tool to see and analyse what's around them. They perceive the world through sound."

But as well as using clicks as a form of sonar, some scientists believe the whales also use them to pass information between each other. Sperm whales sometimes produce special clicks called "coda clicks". When slowed down and viewed on a computer, these clicks reveal almost infinitely detailed layers. Each click contains a series of smaller clicks interlaced within, and a series of even smaller clicks within those, and so on. The time intervals within these clicks are of the order of milliseconds, yet sperm whales can replicate them exactly. They can also make precise revisions, reorganising the pattern of the clicks within a click and then sending it back to a neighbour, all within a fraction of a second.

We want to try and access the information within these clicks and try to show that these animals have a complex language

This is a level of control that humans lack. Our voices vary constantly in volume and frequency, so that the same word spoken twice will never be exactly the same. "Human speech is built on units of sound called phonemes," Schnöller says. "When we speak, we put it in a timescale, like 'I', 'talk', 'to', 'you.' It's analogue. Sperm whale communication is digital. They transmit a thin sound with all the information contained inside it and then they can modulate it, a bit like the way the internet works."
The challenge is to decode the clicks. "We want to try and access the information within these clicks and try to show that these animals have a complex language," Schnöller says.

One reason Schnöller and others are convinced that sperm whales possess a complex language is that they have such advanced brains. Sperm whales have the largest brain of any living animal. At 8,000 cubic centimetres, it is over five times the volume of ours, a comparably minute 1,300 cubic centimetres. What's more, their neurological processes are far more cemented in evolutionary history. The human brain has changed markedly over the past million years, and we have only had the big brains we do now for about 200,000 years. In contrast, the current size of the sperm whale brain has changed little from that of its cetacean ancestors, which evolved some 55 million years ago.

In addition, the sperm whale cortex contains neurons called spindle cells. These long, straggly structures are found in humans and only a small handful of other species. They are thought to allow for rapid communication between distant brain regions, as well as allowing us to feel love, process emotions, interact socially and feel empathy for others. All this suggests that sperm whales are pretty adept thinkers. However, even getting data on their behaviour is long, painstaking and sometimes dangerous work.. read more (and see & hear the whales):
http://www.bbc.com/earth/story/20161206-the-people-who-dive-with-whales-that-could-eat-them-alive