This tooth is believed to be a secondary sexual characteristic or a sensory organ. It has been seen in a drone footage that narwhals also use the tooth to knock out cod fishes in the Arctic. In the dental root or roots, the dentin is covered with cement, which is similar to bone in terms of its composition.
The growth layers of dentin and cement can sometimes be used to determine the age of an individual, much in the same way as how growth rings of a tree are counted. The answer might seem obvious: to eat! However, it is not so simple. Land mammals have several types of specialized teeth that allow them to capture prey or chew or tear their food. Additionally, their upper teeth fit nicely into those of the lower jaw, which facilitates chewing. On the contrary, the teeth of an odontocete whale are very similar to each other and are not designed to fit together, features that say a lot about how they feed.
Indeed, toothed whales catch their prey with their teeth and swallow them whole. However, teeth do not seem to be essential, as whales have already been found with missing or severely worn teeth, or with fractured jaws, but which were nevertheless able to feed. Additionally, females do not always have teeth, especially in some species of beaked whales, but are still able to adequately feed.
In several species, the presence of rake marks can be seen on the skin. Teeth might also be used for social or sexual activities. Known as diphyodontia, this phenomenon is specific to mammals. However, odontocetes are an exception to the rule amongst mammals. They only have one set of teeth, which they keep for life. This dining style favored whales that could both binge feed and were bulky enough to travel far between patches—baleen whales grew to meet the challenge.
And the narrative unfolding from the baleen could inform whale conservation in whole new ways. How did whales make the jump from using teeth to baleen? Researchers from Museums Victoria and Monash University in Australia, with help from Alfred, a million-year-old fossil whale, bring you the latest science.
Baleen is everywhere: long, desiccated slats lie on shelves; a quiver of tall, narrow plates wrapped in plastic, their gummy ends dunked in preservative, leans in the corner. Old baleen splits like fingernails, which reveals its structure: each curved plate is two flat keratin layers with rows of tubules, like miniature coils of tightly rolled luncheon meat, sandwiched between. Filter feeding may have given the mysticetes a way forward millions of years ago, but the oceans are undergoing rapid change today, especially in regions once chockablock with sea ice.
Consider the bowhead whale. It spends its entire life within the Arctic, moving seasonally with the edge of the pack ice as it forms and retreats. Feeding on almost two tonnes of fresh zooplankton daily, bowheads grow large, some to 18 meters, and live long, upwards of years—possibly the longest of any modern mammal. For a baleen researcher, the species is pure gold. It has more and longer baleen plates up to per side at four meters apiece than any other whale, including the gargantuan blue.
Whale-stranding networks provide another source. Older samples, going back to whaling expeditions of the mids, gather dust in museum storage cabinets and private collections, ripe for study. Kathleen Hunt, like Werth, is taking advantage of this resource. Their large size, relatively tiny dorsal fin and mottled gray-blue skin make them relatively easy to identify from the more common, local whales such as the closely related fin whales.
Open mouth and baleen of the right side of a fin whale. Fin whales , Balaenoptera physalus , are second only to the blue in size. At over 60 feet 18 m and over fifty tons, large fin whales are a spectacular sight on Stellwagen. Built for speed, their body is long and sleek. The tail stock is flattened vertically to a thin keel to reduce drag as the wide flukes are pumped up and down for swimming.
A tall dorsal fin probably helps to keep the whale from rolling during high speed swimming, with sprints up to 12 20 km an hour. The overall color tends to be dark brown or warm gray above and cream or white beneath. Fin whales are unusual in that the coloration of the head tends to be asymmetrical: the right hand side of the lower lip, and much of the baleen, is usually stark white as opposed to gray or brown on the left side. Relatively little is known about the movements and behavior of fin whales: they travel quickly and individuals are difficult to identify in the field, making research a real challenge.
Photo-identification of fin whales Agler, has begun to clarify their natural history. In some years, Stellwagen provides good feeding for large numbers of fin whales in spring, summer and fall.
This includes females and their young calves. Many of these whales visit Stellwagen year after year. Just where most fin whales spend the winter, and where or if breeding grounds may be, is still a mystery. Feeding on small schooling fish like sand lance, herring or mackerel, fin whales rely on speed. After locating a patch of bait, fin whales may spend some time circling the school, possibly concentrating the fish. During the final sprint, they may roll on their side, mouth agape, engulfing as many fish as possible.
Massive amounts of oily fish will translate into layers of fat to be used as food storage for the lean times of winter and as milk for growing calves. Fin whales are a cosmopolitan species, found usually in subpolar and temperate seas across the globe. Protected by their speed during the early stages of whaling, abundant fin whale stocks were decimated by the technology of modern whaling: exploding harpoons and engine driven catcher boats. Today they are listed as Endangered by the U.
Three photo identification shots of sei whales from Stellwagen; are they different individuals? Sei whales , Balaenoptera borealis , are another little-known whale species that is found only sporadically on the Bank. Their long, streamlined shape is reminiscent of the closely related fin and minke whales; a body design built for efficient speed. At sea they are easily confused with the larger fin whales but, they tend to be a dark, cool gray, the dorsal fin tends to be smaller and more falcate sickle-shaped , and they are symmetrically colored about the head.
They also tend to be smaller than fin whales, rarely pushing 15 m 50 feet. By all accounts, inshore sightings of sei whales tend to be sporadic and, likely, are related to abundance of their prey.
Records from northern whaling stations reported that most sei whales had copepods in their stomachs as well as krill and small, schooling fish.
This varied diet is reflected in their feeding styles: they can be found travelling slowly, just below the surface, mouth open, skimming for zooplankton likely copepods or, lunging through patches of fish or krill with the rorqual pleats extended, as they gulp feed.
Sei whales may be a good indicator of cyclical changes on Stellwagen Bank. For example, during the summer of Schilling, , whale-watchers were surprised by the fact that very few humpback whales were present on the Bank. Copepods, the main source of food for sand lance, exploded in their absence, creating a temporary hot spot for feeding sei and right whales Perhaps coincidentally, one of the few sightings of a blue whale, another planktivorous species, came from this year as well.
Like fin whales, sei whales were not heavily hunted until the advent of modern whaling. As high speed vessels evolved, the sei whale population crashed. They are listed as Endangered on the U. Endangered Species List and are poorly understood. Note the white flipper patch; variable areas of light patches on sides. Minke whales , Balaenoptera acutorostrata , are the smallest baleen whale species on Stellwagen Bank.
At about 8 m 25 feet long , they have a sleek body design built for speed. Like many marine animals they are counter shaded: dark on top dorsally for camouflage when viewed from above, and light below ventrally to blend in with the light at the surface when viewed from below. Baleen used for artistic purposed is often dyed a deep black color in order to create a uniform appearance. In addition to retail restrictions, transporting legally purchased baleen pieces or art crafted from baleen across international borders often leads to confiscation, making for a variety of problems when one purchases baleen craft work in Alaska and brings their prize into bordering Canada by land.
Corset image is from the Victoria and Albert Museum. Image of baleen eyeglasses is from Antique Spectacles. Sources linked within. Did anyone else get here by googling "beautiful barely legal whale"? The A.
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