Page 136 - World of Animals - Book of Sharks & Ocean Predators

Sharks & Ocean Predators
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In the deep, cool waters of the frozen Arctic Circle lives tusk and some females can have
an elusive creature that has long been the stuff of legend. a tusk.”
Piercing the glassy surface of the waves, a giant needle- In the middle ages, narwhal
like tusk charges skyward, spiralling through the spray. tusks were thought to be able
Another follows this, and another, until the ocean’s ice- to cure ailments, possibly
strewn seascape is a pincushion of gently swirling spears. because they were touted
This display can only belong to one animal: a mottled- and sold as mythical unicorn
grey, ocean-going beast that is unique in the animal horns. It’s rumoured that
kingdom in so many different ways – the narwhal. in the 16th century Queen
Growing to around four to five metres (13.2 to 16.4 feet) Elizabeth I purchased a

in length with elegantly fluked tails, and living to around narwhal tusk for £10,000

50 years of age, narwhals are cetaceans, belonging to the – the price equivalent of a
same group as dolphins and porpoises. “They are Arctic whole castle. Theories behind
whales,” explains Dr Martin Nweeia of Harvard School of the use of the tusk include
Dental Medicine’s Department of Restorative Dentistry spearing fi sh, regulating
and Biomaterials Sciences. Dr Nweeia is the principal temperature, breaking ice,
investigator for Narwhal Tusk Research, and he and his defending their young and as
team have been studying these whales for over 14 years. a dominance display in social
This colossal tusk is what makes the narwhal look hierarchies. “The most general
like nothing else in the ocean. Long, slender and with one that is accepted, and still has
an anti-clockwise spiralling pattern that extends right validity, is that it’s a secondary sexual
to the tip, this is the very thing that has placed these characteristic,” continues Dr Nweeia. This
marine mammals in the realms of fairytale and whimsy. is a feature that distinguishes the sexes,
The sword-like tusk is actually an overgrown tooth that but isn’t directly used in reproduction. Mostly
protrudes out of the whale’s lip, made of similar stuff to male narwhals develop the tusk, so this is why the
our own pearly whites. “The narwhal has eight pairs of explanation fi ts well.
teeth that could form,” Dr Nweeia tells us. “But six of those Dr Nweeia and his team put tusk samples under the
[pairs] are genetically silenced at birth.” This means that microscope to shed new light on their structure and
they simply don’t ever develop. One set forms the tusks. function – what they found was staggering. Although the ABOVE The team had to study the
“In the female [those teeth] typically are embedded in tusk can be all of the things suggested by many other reactions of narwhals to certain stimuli
to test the purpose of their tusks
the bone, so they remain. You don’t see them, but they’re scientists – a secondary sexual characteristic, a tool for
there. In the male the one on the right is embedded and defence or poking, a tool to break ice – there is one other
the one on the left characteristically forms as the tusk. job accomplished by the tusk that is far more important
That being said, there are different expressions. Some above all others. “This tusk is a giant sensor. It has the
whales can have two tusks. Some males may not have a capability of understanding its ocean environment. That

NARWHAL
Monodon monoceros
Class Mammalia

Territory Arctic circle
Diet Carnivore
Lifespan 50 years
Adult weight 1,600kg /
3,500lbs
Conservation status

NEAR THREATENED

“In the 16th century Queen

Elizabeth I purchased a
narwhal tusk for £10,000”

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