Happy monster fish & blue blooded crabs - Survivors: Nature's Indestructible Creatures

I recently spoke with Professor Richard Fortey when he visited Bristol. He was full of excitement about 'Survivors' - the first TV series he has fronted, and about time too!

To palaeontologists he's known as the world expert on Trilobites - an extinct wood-louse like creature, of which there are over 20,000 different species. Trilobites dominated the oceans fauna for over 270 million years making them one of the most successful groups ever, and keeping Richard Fortey busy for over 50 years at the Natural History Museum in London. I remember when I worked at the Museum, whenever Professor Fortey passed there was a hushed reverence, the like of which I have only ever witnessed in the presence of Sir David Attenborough.

The Happy Coelacanth

To most non-palaeontologists Richard Fortey is best known for his popular science books, the most recent of which is 'Survivors, the plants and animals that time left behind', on which this series is based.

There lived a happy Coelacanth
In dim, primordial seas;
He ate and mated, hunted, slept,
Completely at his ease.
Dame Nature urged: ‘Evolve!’
He said: ‘Excuse me, Ma’am,
You get on with making Darwin,
I’m staying as I am.’

This curious little poem by Horace Shipp (1988) is cited in the book, and it wonderfully captures the essence of Fortey's thesis; that while some lineages change dramatically over time, others do not. Of course it is not enough to just accept that, and what Fortey does beautifully is to explore why this should be.

The star of Shipp's poem is a prehistoric fish, the coelacanth. This was thought to have disappeared with the dinosaurs 65 million years ago and then astonishingly turned up in a South African fish market in the 1930s. It turns out that it had been surviving quite happily in the gloomy depths around the Comoros Islands.  'Unfortunately there's some sort of civil war happening in the comoros so it wasn't the best time to visit' regrets Fortey, but 'who knows what other creatures from the past remain waiting to be discovered'.

'I was lucky to see so many wonderful plants and animals whilst making this series' he says with boyish enthusiasm, his eyes twinkling. This passion for prehistoric life began when he was 14 years old and first 'gazed into the eyes of his first trilobite'. 'So where better to start my exploration than with the closest living relatives of the creatures I know best'.

Fortey headed to the shores of Delaware in the United States to witness a scene that has been taking place for at least 100 million years. On a few nights every May and June, when the moon is full and the tide is at its highest, creatures called horseshoe crabs come ashore, emerging in their tens of thousands to spawn and lay their eggs in the sands along this protected bay. 'They're not crabs at all but a special group called Limulidae, the nearest living relative of the trilobite.' 





I too have had the pleasure of filming this spectacle (see my post from May 2011)  but I was there for a much more modern sight. The laying of  billions of horseshoe crab eggs is the stimulus for a million migrating shorebirds - Red Knots, Semipalmated Sandpipers, Ruddy Turnstones, and Sanderlings, who gather to feed on these tiny beaches. Many fly thousands of miles to be here. It's a critical stop-over to fatten up on their way to the breeding grounds of the arctic, and each bird needs to eat more than 135,000 eggs in less than a couple of weeks. As Fortey says 'Birds have only been around for less than 90 million years' so here we have a modern ecosystem completely reliant on survivors from the past'.

This was not the first time that Richard Fortey has been up close with these alien-looking creatures. In south east Asia he was surprised to find one served up for dinner, and as it was the closest thing to eating a trilobite he tucked in with gusto. He told me that 'it was utterly disgusting', and maybe this is one of the secrets to the longevity of the horseshoe crab.

Having been around for 450 million years horseshoe crabs have had to face bigger challenges than hungry professors. They had to face the greatest extinction event the planet has ever seen, and the catastrophe that wiped out their more diverse and flamboyant cousins - the trilobites. Dubbed The Great Dying, this disastrous loss of life occurred around 250 million years ago. It was the demise of most of earths species - 96% of marine species, 70% of terrestrial vertebrates and 57% of insect families. This period had phases of major environmental change, ending with a catastrophic event, which included some of the greatest volcanic activity the world has seen.

But the strange-looking horseshoe crab, with its armoured shell and long rigid pointed tail, plodded on. So, what is it about horseshoe crabs that enabled them to survive? ‘Being able to feed on almost any organic matter helped,’ says Fortey but what 'I think is the real key to their success is that they have a special kind of blood, which is blue! rather than iron based like our own, it's copper based.' 'It coagulates when it encounters bacteria so they can 'wall up' any wounds they receive. In Delaware you see giant crabs with huge holes through them, and they just carry on regardless'.

'What is absolutely wonderful is that scientists are able to use this blue blood to test drugs and implants for toxins' 'The crabs are milked like cows..' 'but fortunately' he added 'the scientists have come to their senses and now return the crabs in a fairly healthy state.'

So what has helped the horseshoe crab to keep going for 450 million years might also be able to help us keep going a little longer too.

During filming Fortey encountered a cast of some of the most peculiar animals on earth including velvet worms, lungfish, sponges and flesh-burrowing sea lampreys, but his highlight was the duck-billed platypus, whose lineage goes back more than 200 million years.

‘Seeing duck-billed platypuses was a thrill. I know the one on display at the Natural History Museum  museum but they are such peculiar animals that to see them alive was something I had wanted to do for a long time.  I had had two previous unsuccessful attempts to do so’

If you haven't see this series yet then you can catch up (while it lasts) on BBC iPlayer.