The World’s Oldest Animal

Ferrebeekeeper has written a lot about how long trees can live.  Individual yew trees can survive for thousands of years, bristlecone pines can live even longer, and clonal entities like Pando, a super-colony of quaking aspen, can potentially live for hundreds of thousands of years.  Likewise colonial animals (coral, gorgonians, tubeworms, and so forth) tend to live the longest—although the constituent individuals come and go.  Yet colonial animals frustrate our selfish human perception of the world.  When we talk about an organism we mean an individual, and in this category, the world’s longest living animal comes as a surprise!

Arctica islandica

As you read this, somewhere, off the coast of Greenland or Virginia there is a smug little clam which was alive when Oliver Cromwell was in diapers and before Galileo discovered the moons of Jupiter. Arctica islandica, the “Ocean Quahog” or “Black Clam,” is believed to live for more than 400 years!  The little bivalve laughs at nations, dynasties, and vampires as short-lived.

The venerable mollusks do not live flashy or extravagant lives. They live under a light drift of substrate on Atlantic coastal shelves at a depth of 25 to 100 meters (75 to 300 feet) although they have been found much deeper.  The species is very successful and ranges from coastal Portugal up around Iceland down to the Carolinas.  The little clams feed on plankton suspended in the water and they only grow to about 12 cm (5 inches) in diameter.  Amazingly these Methuselah mollusks are harvested by dredge for the dinner table, so if, like me, you love spaghetti alle vongole, you might have inadvertently eaten something that lived longer than the United States has been around!

James Fort at Jamestown ca. 1610 (to give some perspective on how long 400 years is)

The secret behind the small bivalve’s longevity is unclear.  Some scientists have speculated that antioxidant enzyme activities and the avoidance of waste accumulation are partially responsible for the clam’s age but the British Society for Research on Aging somewhat dryly remarks that, “Despite interest in this clam’s longevity and the measurement of growth increment series, little research into how this species has apparently managed to defy the onset of the ageing processes has been conducted.”

This shines a poor light on our priorities. Instead of grasping the molecular secrets of the longest living animals on Earth, the people who allocate resources to various things have decided to buy learjets and build a bunch of hokey Mcmansions for themselves.   Argh! Maybe the clams’ sense of frugal austerity is what gives them such staying power.

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The Yew

Here we are at the end of tree week—an event which isn’t real anywhere but on this blog and which I didn’t even realize was happening until now.  But don’t worry, I’ll be writing more about trees in the future.  I really like them. Anyway, to close out this special week I’m going to write about one of my very favorite trees, the yew.

Yews are a family (Taxaceae) of conifers. The most famous member of the family is Taxus baccata, the common yew, a tree sacred to the ancient tribal people of Britain and Ireland.  Although their strange animist religion was replaced by Christianity, a cursory look at the literature and history of the English, Irish, and Scottish will reveal that the yew has remained sacred to them–albeit under other guises.  The common yew is a small to medium sized conifer with flat, dark green needles.  It grows naturally across Europe, North Africa, and Southwest Asia but the English have planted it everywhere they went (so pretty much everywhere on Earth).  Yews are entirely poisonous except for the sweet pink berry-like aril which surrounds their bitter toxic cone.  The arils are gelatinous and sweet.

The Fortingall Yew in Scotland

Yews grow very slowly, but they don’t stop growing and they can live a very long time.  This means that some specimens are ancient and huge.  The Fortingall yew which grows in a churchyard in Scotland had a girth of 16 meters (or 52 feet) in 1769.  According to local legend Pontius Pilate played under it when he was a boy.  This is only a legend: Pilate was not in Britain during his youth.  The Fortingall yew however was indeed around back in the Bronze Age long before the Romans came to England.  The oldest living thing in Europe, the yew is at least 2000 years old.  According to some estimates it is may be thousands of years older than that.  It was killed by lackwits, souvenir hunters, and incompetent builders in the early nineteenth century…except actually it wasn’t.  The tree merely went dormant for a century (!) before regrowing to its present, substantial girth.  It is one of the 50 notable trees of Great Britain designated by the Exalted Tree Council of the United Kingdom to celebrate their revered monarch’s Golden Jubilee.

The Llangernyw yew tree in Llangernyw Village, Conwy, Wales

As noted, the people of the British Isles loved yews but they loved their horses and livestock even more and objected to having them drop dead from eating the toxic plant.  This means that they planted the tree in their cemeteries and churchyards (or, indeed, built their churches around ancient sacred groves).  According to pre-Christian lore, a spirit requires a bough of yew in order to find the next realm.  Many English poems about death and the underworld incorporate the yew tree as a symbol, a subject, or, indeed as a character.  Aristocrats also had a fondness for yew because it could be sculpted into magnificent dark green topiary for their formal gardens.

Yews as topiary in the formal garden of Levens, Cumbria

The substantial military prowess of the English during the middle ages depended on longbows made of yew.   A good bow needed to be made from a stave cut from the center of the tree so that the inelastic heartwood was next to the springy outer wood.  This meant that yews in England were badly overharvested and the English had to continually buy yew from Europe. To quote Wikipedia “In 1562, the Bavarian government sent a long plea to the Holy Roman Emperor asking him to stop the cutting of yew, and outlining the damage done to the forests by its selective extraction, which broke the canopy and allowed wind to destroy neighboring trees.”

Like many toxic plants, the poisonous yew has substantial medical value.  The extraordinary Persian polymath Abū ‘Alī al-Ḥusayn ibn ‘Abd Allāh ibn Sīnā’  (who is known in English as Avicenna) used yew to treat heart conditions in the early eleventh century—this represented the first known use of a calcium channel blocker drugs which finally came into widespread use during the 1960’s.  Today chemotherapy drugs Paclitaxel and Docetaxel are manufactured from compounds taken from yews.  It is believed that the yew’s fundamental cellular nature might yield clues about aging and cellular life cycles (since the yew, like the bristlecone pine, apparently does not undergo deterioration of meristem function).  In other words, Yews do not grow old like other living things.

A final personal note: I naturally put a yew tree in my walled garden in Park Slope.  It’s the only tree I have planted in New York. It grows very slowly but it is indifferent to drought, cold, or the large angry trees around it. It will probably be the only plant I have planted to survive if I abandon my garden.