Super exhibit with a point to make

THE Natural History Museum, closed for three years following the collapse of a staircase, has reopened in Dublin’s Kildare Street.

The place has been given a facelift, new lighting has been installed, specimens have been cleaned or replaced but, thankfully, the unique 19th Century ambience of this venerable institution is still intact.

Irish wild creatures are exhibited on the ground floor, while the first floor has a selection of large animals from elsewhere in the world. These include the walrus, a species which occasionally visits Ireland, and skeletons of whales which frequent our coast. There isn’t enough room for them on the ground floor.

Two long spikes are on show. Resembling the lances of jousting Medieval knights, these are tusks of one of the world’s most bizarre sea mammals. A male narwhal, weighing one and a half tonnes, has a cone up to three metres long, protruding from his head. Most North Atlantic whale species have been recorded in Irish waters but the narwhal is an exception. There are a few records from the North Sea but the whale with the tusk has not been seen here. A cold-water specialist, it catches fish at the edge of the polar ice-cap and seldom ventures far from icy waters. As temperatures rise in the North Atlantic, it’s unlikely that the narwhal will ever be added to the list of Irish whales.

Narwhal means corpse whale. Adults, whitish and blotched, resemble the body of a drowned sailor which have been in the sea for several days. This mysterious animal is a bundle of contradictions. As one of the toothed whales, the group to which porpoises orcas and the Dingle dolphin belong, you would expect the narwhal to have a good set of teeth. However, it only has two, one on each side of its mouth. The absence of teeth is odd in a creature which lives mainly on fish. Narwhals, diving for up to 20 minutes at a time, suck food down their throats without biting or chewing on it.

As a male narwhal approaches maturity, the tooth on the upper left side begins growing outwards from its face, twisting like a corkscrew as it develops. Ironically, this toothless animal soon sports the longest tooth found in the animal kingdom. Sometimes, both of its teeth develop into tusks, but one is always shorter than the other. Very occasionally, a female grows a tusk.

How extraordinary that a creature which earns its living by fishing should go around with a spike, half the length of its body, projecting from its mouth! This useless appendage, weighing up to 10kg, must seriously limit the animal’s manoeuvrability and scare off the fish it is trying to catch. The enormous antlers of the giant Irish deer existed only to impress females. Peacock’s tails have a similar function. The narwhal’s tusk is another such courtship adornment; bulls indulge in fencing matches to display their credentials. Rivals don’t actually stab each other, but almost two thirds of spikes are broken in these jousts. Those with the most impressive weapons secure the lion’s share of matings and this ensures that future generations will continue in the great tusk tradition.

But the narwhal is odd in other respects. Its tail is shaped like the fans upper-class ladies used on social occasions long ago. Contrary to the normal configuration of whales and fish, the curved side of the fan is at the tip of the tail. Toothed whales generally have a prominent dorsal fin which gives them leverage, like a boat’s keel, when they turn sharply to right or left. Narwhals, however, have no dorsal fin. Why the configuration of their fins and tails should be so odd is not understood; narwhals hunt in darkness at such great depths that scientists can’t study them.

Although the narwhal is not Irish, the coat of arms of the British crown features a unicorn. On most representations of the mythical animal, the horn is corkscrew-shaped like a narwhal’s spike. Perhaps this strange whale gave rise to the notion of unicorns. At any rate, the extraordinary tusk deserves a place even in a museum devoted mainly to Irish natural history.