Finnhval

The members of rorqual whales (Balaenopteridae) are easily to distinguish from other baleen whales by long furrows stretching from the mouth along the throat to the navel. Some members of this family are the blue (Balaenoptera musculus) and the fin whale (Balaenoptera physalus) which are the biggest animals on earth. One potential reason of their size is their ability to lunge feed, which is a unique feeding style for rorquals. The animals swim with an open mouth, which in this position is almost vertical to the rostrum, to flood it with amounts of water and krill which can be greater than the whale itself. During this process the furrowed skin expands immensely, meaning that the nerves in this skin must be highly endurable to this movement. Vogl et al. studied these nerves from fin whale carcasses in Iceland. They found that the nerves can double their length and can return to normal length without a problem. The secret behind this “bungee cord” behaviour are folded nerve fibre fascicles concentrated in a small core of the nerve and a thick wall of elastin fibres and highly folded collagen fibres around it. During a lunge, the core nerve fibres and collagen fibres unfold while the elastin fibres stretch. The collagen fibres become taut to prevent overstretching, thus the nerves are not really stretched but the fascicles unfold while the whole nerve just increases in length. In general, nerves are not very extensible like this and ‘nerve stretch injury’ is the most common type of nerve trauma in humans. Therefore, these highly extensible nerves could be one of the most important functions in rorquals which enabled the evolution of these large whales.The discovery of the Charlotte whale, as the Vermont’s fossil is known, helped to explain the geology and glacial history of North America. Thanks to this and other marine fossils and sediments found in the region, we now know that portions of Ontario and Quebec (Canada) and the US states of Vermont and New York were not so long ago covered by the Champlain Sea, an arm of the Atlantic Ocean that once extended from the Gulf of St. Lawrence to the Great Lakes. The Champlain Sea was short-lived and formed when the ice retreaded from this area 13,000 years ago, leaving a deep basin that was filled with water from the Atlantic Ocean and became populated by marine mammals such as belugas, fin whales, bowhead whales and walruses. Free from the pressure of tons of ice, the earth crust slowly rebounded until, 3000 years later, the land was again above the sea level, the connection with the Atlantic Ocean closed and the basin transformed into the freshwater river valley it is today.