At 400, clam may be longest-lived animal known
Nov 16,2007 00:00 by Bend_Weekly_News_Sources

Can you im­ag­ine liv­ing four cen­turies? Sci­en­tists say they’ve found an an­i­mal that did just that: a qua­hog clam, Arc­tica is­landica, that lived and grew in the cold wa­ters off Ice­land’s north coast for at least that long.

When Shake­speare was writ­ing his great­est plays, the re­search­ers say—when Gior­da­no Bru­no was burnt at the stake in Rome for claim­ing in­fi­nite hab­it­a­ble worlds ex­ist—this mol­lusc was but a ten­der youth, ob­liv­i­ous to these de­vel­op­ments.

Courtesy Bangor University

The Guin­ness Book of Records gives the cur­rent rec­ord for long­est-lived an­i­mal to an­oth­er Arc­tica clam, age 220, col­lect­ed in 1982 from Amer­i­can wa­ters. Un­of­fi­cial­ly, the rec­ord be­longs to a 374-year-old Ice­land­ic clam found in a mu­se­um. 

Both these rec­ords, the re­search­ers said, seem to have been eclipsed by the lat­est spec­i­men, whose age, 405 to 410 years, they as­sessed by count­ing an­nu­al growth lines on its shell.

The sci­en­tists, from Ban­gor Un­ivers­ity in the U.K., are scle­ro­chro­nol­o­gists, who study clam growth and age us­ing growth lines much as den­dro­chro­nol­o­gists study tree growth us­ing tree-rings. Clam shell growth is re­lat­ed to en­vi­ron­men­tal con­di­ti­ons such as sea tem­per­a­ture, salin­ity and food avail­abil­ity. The Ban­gor team an­a­lyses the growth his­to­ries to un­der­stand changes in the ocean linked to cli­mate change.

The clam was dredged up by Paul But­ler and James Scourse of the un­ivers­ity dur­ing a re­search cruise last year as part of a Eu­ro­pe­an Un­ion in­ves­ti­g­ati­on of his­tor­i­cal cli­mate changes. The dis­cov­ery was made by Al Wan­a­ma­ker, the new­est mem­ber of the un­ivers­ity’s “Arc­tica” team, said mem­ber Chris Rich­ard­son. “Al and Paul rushed up to my of­fice to an­nounce that they had found a rec­ord-breaker,” he re­counted. Fur­ther ex­am­in­ati­on, he said, con­firmed the clam had beat­en the pre­vi­ous rec­ord by three de­c­ades.

Why do these clams live so long? The Ban­gor in­ves­ti­ga­tors be­lieve the mol­luscs may have evolved excepti­onally strong defenses against de­struc­tive ag­ing pro­cesses. “If, in Arc­tica is­landica, evoluti­on has cre­at­ed a mod­el of suc­cess­ful re­sist­ance to the dam­age of ag­ing, it is pos­si­ble that an in­ves­ti­g­ati­on of the tis­sues of these real life Me­thu­se­lahs might help us to un­der­stand the pro­cesses of ag­ing,” said Rich­ard­son.

Courtesy Bangor University and World Science staff