Demystifying the Narwhal’s Tusk

Male Narwhal, Photo Credit: Rex

Yet again drones have proved an invaluable instrument for new discoveries, especially when it comes to observing marine mammal behavior (see my past post: Whale Tales – Current Cetacean Communiqués).  The subject in question this time is the strange and elusive Narwhal.

Humans have valued Narwhal tusks for centuries, perceiving them as a cure for a number of medical ailments including epilepsy and poisoning, a practice which is still alive and well in Japan. Inuits still carry on the tradition of culling narwhal for subsistence and often used the tusks for carving. However, we have had little knowledge about the value of the tusk to the animal itself until recent years. More current research and observation suggests the tusks of narwhals function in multiple capacities.

The edited footage above conveniently highlights moments where individual narwhals stun passing cod with a solid tap of their tusk. It’s an interesting hunting method, but one that is rivaled by other examples in the marine world. Many species immobilize their prey; some, like sailfish, use similar techniques, while others may use contrasting tools. Electric Rays and eels shock their quarry, while pistol shrimp use high-speed cavitation bubbles to daze their targets. Archer fish knock their dinner out of overlying branches by spitting a stream of water at them.

The purpose of the narwhal’s tusk likely doesn’t stop at clubbing unwitting prey. The absence of an enamel coating on their tusk supports the idea that these animals might be using them in a sensory capacity, allowing the specialized tooth to come into contact with surrounding water masses to detect environmental changes such as salinity and temperature, as well as chemical cues in the water associated with food and mates. Pairing this awareness of their surroundings with highly directional echolocation also allows them to find sometime slim openings in Arctic ice coverage where they can surface and breath as needed.

 However, these animals may still suffer catastrophic events living in the extremes they do. Pods of narwhals occasionally suffer entrapments when rapidly shifting weather conditions cause unexpected freezing over potential air holes leading to open water. Kristin Laidre, a researcher at University of Washington’s Polar Science Center, noticed the frequency and timing of those events may be changing with recent shifts in Arctic climate. This, paired with a variety of additional stressors to the whales’ habitat, is the focus of one her current research projects examining the behavioral ecology of narwhals in a changing Arctic. She and other researchers have tagged the animals on multiple occasions in Canada’s Baffin Bay to track their movement, the depth of their dives, and associated water temperatures. As it turns out the temperature data has proved useful to other scientists interested in climatology data. Laidre is soon hoping to once again utilize the oceanographic power of narwhals, this time in Greenland.

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