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A previous Ferrebeekeeper post described the largest living bivalve mollusk–the magnificent giant clam which is indigenous to the South Pacific. However there are other large bivalve mollusks out there which are nearly as remarkable (and possibly even stranger looking). One of these creatures, the geoduck clam (Panopea generosa), causes a unique amount of controversy, pride, consternation, and outright greed along the Northwest coast of North America where it lives
Geoduck Clam (Panopea generosa)
Geoducks are the largest burrowing clams in the world. Specimens weighing up to three pounds (0.5–1.5 kg) are widely known and 15 kilogram monsters are alleged to exist. Although the clams’ shells can grow quite large–sometimes exceeding 20 cm (8 inches) in length–the outstanding features of geoducks are their obscene siphons/necks which regularly reach 1 metre (3.3 ft) long (and can reputedly grow to twice that length). Thanks to these long necks, geoducks can bury themselves deep in the coastal sands while still filtering huge amounts of plankton rich water through their digestive system. . Geoduck (which is apparently pronounced “gooey duck”) is a word from the Lushootseed language, a tongue spoken by the Nisqually tribe. It means “dig deep” although the Chinese name for the clams “xiàngbábàng” (which means “elephant-trunk clams”) seems equally apt.
Geoducks of Wasshington and British Colombia do not have many natural enemies (although apparently in Alaskan waters they are preyed on by sea otters and dogfish). If left undisturbed, the bivalves can live to the fabulous age of a century-and-a-half. Lately however, the geoducks, which dwell in giant cold-water colonies beneath Puget Sound, are being gobbled up en masse by humankind. Although Anglo-Saxon settlers to the Pacific Northwest found the suggestive sight of the clams to be unbearable, the mollusks are hugely popular in China and Asia, where price can exceed US$168/lb (US$370/kg). Chinese diners believe that the geoduck’s…manly shape indicates that the unpreposessing mollusk will act as an aphrodisiac for those who consume its flesh. Price has shot upwards as China’s economy has grown.
Wow--Puget Sound is Beautiful.
In order to cash in on this bonanza, aquaculturists are attempting to stake out larger and larger swaths of coastline as geoduck farms. Such use of the tidelands causes consternation to real estate developers. Not only do developers object to the unaesthetic appearance of PVC pipes used as nurseries for juvenile geoducks, but the interests of both parties are entirely opposite. Coastal land development involves bulkheaded beachfronts, deforested land, and nitrogen waste from gardens and septic systems—all of which are inimical to successful geoduck beds.
As the conflict rages on, some people (figuratively!) embrace the geoduck and its strange appearance for non-financial reasons. The Evergreen State College of Olympia, Washington has adopted the remarkable burrowing clam as a mascot. Although the school’s official seal features a conifer tree, the unofficial coat of arms features a geoduck rampant d’or on a rondel azure (or however you say that in heraldry speak). Additionally the school’s teams are all named the geoducks and they actually have a guy dressed up like a giant filter feeding clam to root for them.
"Speedy" the Geoduck--don't even ask about the fight song....
Grant's Golden Mole (illustration from Michigan Science Art)
Yesterday I spent some time describing the Namib Desert (as well as giving a brief overview of the entire nation of Namibia). I did this not just because Namibia strikes me as one of the most striking landscapes on earth, but because the harsh habitat is home to a profoundly strange mammal, Grant’s Golden Mole (Eremitalpa granti), a solitary, nocturnal predator of the Nagib Desert. Grant’s golden mole lives primarily in the Namib Desert but ranges as far north as Angola and as far south as the arid dunes of South Africa.
The golden moles are already strange animals. The name “mole” is a misnomer: golden moles are not closely related to the true moles (which are insectivores) or to the marsupial moles of Australia. Their taxonomical classification is presently unclear but they seem to be most closely related the tenrecs, a group of insect eating primitive placental mammals. Tenrecs and golden moles both have unusual dentition (a critical feature to the taxonomist) and possess cloacas like birds. It has been speculated that tenrecs and golden moles are closely related to the first placental mammals, but this may be a mistake. It is also possible that the tenrecs resemble the ancestral placental mammal of long ago whereas golden moles have evolved features which uniquely suit their desert environments.
Van Zyl's Golden Mole (Cryptochloris zyli) photo from "Professor Paul's Guide to Mammals"
Grant’s golden mole is a particular anomaly since it is so profoundly suited for desert living (which may have to do with the great age of the Namib Desert). Grant’s golden mole does not make permanent burrows but literally swims through the sand. The creature has powerful claws for digging which have almost some to resemble “sand flippers”. It can move swiftly underground and detect its prey (termites, scorpions, and lizards) through its profoundly acute sense of touch. Its eyes have become vestigial and are covered with both skin and fur. Because it burrows through fine particles of sand, its coat is incredibly fine and dense, its nose is a leathery wedge, and its ears have shrunk to tiny, tiny openings.
Grant's Golden Mole
Grant’s golden mole does not build burrows so it is not known how or where it raises its young. Because water is so scarce in the Namib Desert, the golden mole does not drink: its kidneys are hyper efficient. It also does not regulate its temperature in the manner of other mammals and it is capable of dropping into a suspended state during the days (when it digs deep down into the oxygen poor sand). Grant’s golden mole requires large swaths of sandy desert for hunting. It lives only on the shifting dunes. With such a lifestyle you would think that it has escaped trouble from humankind, but you would be wrong. The giant sand mines of Namibia are eating into its habitat and it is preyed on by feral cats. In so far as we know anything about its numbers, we believe it is threatened. Even in one of the most inhospitable places, humans are making inroads.
Grant's Golden Mole after a Successful Hunt (Minden Pictures)
Common Wombat (Vombatus ursinus)
It’s the final day of Furry Mammal Herbivore week which has so far featured two different lagomorphs, one rodent, and the enigmatic hyrax. To mix things up a bit we are ending with a marsupial–the stolid wombat. The wombat’s unusual moniker comes from the Eora language which was spoken by the Aboriginal people who originally inhabited the Sidney area. There are three species of wombats and all are powerful burrowing herbivores which are active mostly at twilight and at night. Wombats are marsupials but the openings of their pouches face backwards to prevent dirt from getting inside as they dig. Although wombats are not often seen, their presence can be identified by the many burrows which they excavate and by their distinctive cubic scat which looks like bouillon cubes (you’ll have to look it up on your own).
Wombat physiognomy betwrays their close relation to koalas.
Wombats are larger than this week’s other herbivores, reaching nearly a meter (3 feet) in length. Although they are preyed on by dingos and Tasmanian Devils, their large muscles and heavy claws give them some protection (as does their tailless haunch which is composed largely of dense cartilage). A predator following a wombat into a burrow is confronted not only with the shield-like flesh of their rear-quarters but also with fearsome donkey kicks from their powerful back legs. Wombats are never far from their burrows since they construct up to 12 at various spots around their territory. Even if they are related to the dimwitted koalas, wombats are said to have a more complicated brain than other marsupials (although their intelligence in no way approaches that of the brilliant monotreme echidna) and they often surprise trappers and zoologists with their clever evasive thinking. Additionally, when hard pressed, they can run 100 meters in less than 10 seconds—impressive when one learns the human world record is 9.58 seconds.
Death of a Wombat (Dante Gabriel Rossetti, 1869, pen and ink)
Dante Gabriel Rossetti, painter, poet and weirdo, used the wombat to parody the Victorian taste for overly lugubrious gothic melodrama in his sad drawing “The death of a Wombat” (above). The drawing shows a plump 19th century gentleman weeping for his deceased wombat friend while declaiming the following lament:
I never reared a young Wombat
To glad me with his pin-hole eye,
But when he most was sweet & fat
And tail-less; he was sure to die!
The work might be a parody but I find the poor dead wombat curiously affecting. Fortunately all wombats are now protected by Australian law. Despite such protection, the creatures are still having trouble competing for grazing with cattle, sheep, and above all rabbits. Hopefully wombats will continue to endure–the endearing little bulldozers are an irreplaceable component of Australia and Tasmania.
Aww!
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