Friday, August 12, 2011
The world's biggest babysitters: How sperm whales use their grandmothers to look after young
Daily Mail Online: The world's biggest babysitters: How sperm whales use their grandmothers to look after young
Sperm whales are emperors of the ocean.
They're the loudest animals on earth, and possess the biggest brains of any creature that ever lived. But they are also the greatest living predator, armed with the largest teeth known to nature.
And I've just spent two weeks diving with them, in the waters off the Azores
You might think that's a terrifying prospect. But, in reality, these giants - males can reach 65ft in length, real-life Moby Dicks - are entirely placid animals, far from the mythical monster that sank Captain Ahab's ship.
Extraordinary images revealed a large adult female - about 30ft long - with a juvenile, and three calves. Yet only one of these young could be her own; whales do not give birth to twins or triplets. What we were witnessing was babysitting - on a grand scale.
The Azores are volcanic islands in the mid-Atlantic. Their steeply shelving shores mean they're one of the best places in the world to go whale-watching.
Here, resident populations of female sperm whales gather with their young. Many of the calves are still suckling their mother's milk - extremely rich and 60 per cent fat. (According to one intrepid naturalist I know, it tastes of fishy cottage cheese.)
Adult sperm whales feed almost exclusively on squid, which is why they favour these deep waters
But while they dive for food, using their incredibly loud sonar clicks to scan the ocean, their young calves must stay at the surface, unable to follow their parents.
This presents a big childcare issue. The solution? A babysitter.
Almost uniquely in the animal kingdom, female whales beyond breeding age have an active role, one shared only by elephants and primates.
They may be aunts or grandmothers (and can reach 100 years old or more) or they may not even be genetically related to their charges at all.
Nevertheless, they patiently take care of the young whales at the surface, waiting for the feeding mothers to return. I’ve seen many things in the whales’ world, but this amazed me: true whale altruism in action.
Under special licence from the Azorean government, observing its strict guidelines regarding the whales’ welfare, photographer Andrew Sutton and I prepared to dive in the waters off the island of Pico.
I last met the Azores’ whales four years ago, a memorable encounter which became the climax of my book Leviathan and BBC film Arena: The Hunt For Moby Dick. Now, I was eager to renew our acquaintance.
Bouncing in a fast rib — rigid inflatable boat — skippered by the young Azorean captain, João Quaresma, we zoomed out of Lajes harbour and into the open Atlantic.
A few miles out to sea, we stopped. João had seen the distinctive blow of at least one whale at the surface. I yanked on my wet suit, fins and mask. On João’s command, Andrew and I slipped into the water.
Plunging into a fathomless sea is still pretty scary, even though I’ve done it many times now. Although the water looked calm and blue from above, below the visibility was drastically reduced.
It never ceases to amaze me that you can be 20ft from a whale and not actually see it. As my heart began to beat faster with anticipation, suddenly they appeared, literally out of the blue.
Not just one or two, but a group of five animals. My fear fell away, to be replaced by a big grin. I was back with the whales. It was like meeting old friends.
It is an extraordinary sensation to share the water with such gigantic animals. You can almost feel their presence and sense their intelligence. They are truly beautiful, mysterious mammals.
One of the tantalising aspects of watching whales from the surface is how little you see of them. But underwater, every exquisite detail is revealed.
Each animal is a different shade — grey, brown, even a faint tint of lavender, as the sunlight plays on their bodies through the water. Their mouths glisten pearly white, with the same paleness that flecks their bellies.
I watched as the calves twisted and turned around the adult female, constantly brushing and rolling against her great grey flanks for reassurance.
They may be loud when hunting but, at the surface, sperm whales are eerily silent. That just made the experience more dream-like.
It was an emotional moment for me, to see these huge creatures physically express their solidarity and dependence on one another.
I was so close, so caught up with the group, that later a friend joked that maybe they wanted to adopt me.
Again and again we entered their domain. One inquisitive calf came up close, peering at me.
Very young, it was plump and unwrinkled (as they age, the whales’ bodies start to look a little like prunes, as they’ve spent too long in the water).
It was clearly curious about this odd, neoprene-clad visitor. Then it dived, leaving behind a cloud of whale poo which I was able to dodge, just in time.
There’s so much we still don’t understand about these awe-inspiring creatures. Their deep-diving habits — natural submarines, they can plunge more than a mile and stay down for up to two hours - have made them difficult to study.
But now, new technology such as electronic tagging is beginning to reveal amazing facts about sperm whales.
Dr Hal Whitehead, of Dalhousie University, Nova Scotia, has spent a lifetime studying sperm whales, with astounding conclusions. Their society is predominantly matriarchal. They even have a sense of culture, passing information from one generation to the next.
Although we do not know what they use their massive brains for, sperm whales certainly communicate in a series of clicks, not unlike Morse code. Dr Whitehead has discovered that separate ‘clans’ have click ‘dialects’, as different as a Yorkshire accent is from a Devon one.
For sperm whales, roaming the open ocean, such social bonds are all important. Living in three dimensions, their extended families are also their homes - the way they identify themselves.
In the Azores, I saw whale society at work. One afternoon, I watched underwater as a calf suckled at its mother’s belly.
As João, our captain, told me, calves generally start to feed themselves at three or four years. ‘But they’ve found juveniles aged nine years old with milk in their stomachs.’
Teenage males will move off and form ‘bachelor schools’, travelling to higher latitudes and becoming increasingly solitary. But they still return to the ‘nursery schools’ of warmer waters, where they’re greeted with what we would call affection, touching their heads and bodies together.
Mature males have even been seen holding young calves gently in their huge, tooth-studded jaws
On our last day in the Azores, we watched just such a group at the surface. In a flurry of intertwined heads and tails, we saw them opening their mouths, curling their bodies around one another.
It was a bit like watching puppies at play. Clearly, they were having fun. I felt envious of their freedom.
Then, as we were about to leave, two whales headed for our boat. I was sure they would veer off once they came within a certain distance.
To my amazement, they just kept on coming. I realised, as one great head lifted out of the water, that this was a mother-and-calf pair. I stood up excitedly on the prow, nearly overbalancing in the process.
They passed right alongside, so near I could have reached down and touched them. I could see the female on her side, with her calf beside her. I was stunned.
We’d spent two weeks watching whales — now the whales had come to watch us.
With such huge animals so close, we might have feared for our safety. Yet there was nothing but calm in this last encounter with these gentle, curious creatures. It was incredibly touching.
As I looked down, I could see the mother and calf looking back at me.
Perhaps they’d come to say goodbye. I’d rather it was: ‘See you later.’
* For more on responsible whale-watching, visit www.wdcs.org/