Visitor Creator: Sophie Pollard
Palaeobiology MSc Pupil
Whereas residents of town of Bristol and the remainder of the UK will keep in mind the summer season of 2022 for its record-breaking heatwave, information of a unique type have been set within the Bristol Bay space of Alaska, with sockeye salmon returning in larger numbers than any recorded earlier than. That is nice information for the fauna of Katmai Nationwide Park, and by extension, for followers of Katmai Nationwide Park’s Fats Bear Week, an annual occasion through which the bears of Katmai compete to see who greatest drags the competitors, by how a lot their bellies drag alongside the bottom.
Every year, between the months of June and October, the bears of Katmai nationwide park and the Bristol Bay space (Alaska) race towards the clock to place on the kilos earlier than they hibernate in winter, a lifestyle I’m certain many people aspire to. And for an space which boasts extra brown bears than folks, and the healthiest run of Sockeye salmon on the planet, it’s a good time to rejoice the richness of the Katmai and Bristol Bay ecosystem with some chubby Ursidae. Fats bear week started in 2012 and is now celebrating its 10-year anniversary of dwell discover.org cameras posted at Brooks Falls, and naturally the general public vote to find out which well-known bear has placed on probably the most blubber.
This presents an excellent alternative to dive into the geological and ecological historical past of Katmai nationwide park and the broader Bristol Bay space and into the fascinating evolutionary historical past of the brown bear.
Geological Significance – Volcanic Exercise
Katmai isn’t solely well-known for the enormity of its bear inhabitants (in each quantity and measurement). In reality, the world owes its nationwide park standing to its distinctive and interesting geology, notably for its volcanic exercise. The park has over a dozen energetic volcanoes, and eruptions are frequent inside its boundaries, the biggest and most well-known being the 1912 eruption of Mount Katmai and Novarupta volcano, the biggest volcanic occasion of its century.
Big quantities of ash and pumice have been ejected from the Novarupta crater, destroying nearly every part that stood in its method. Volcanic deposits as thick as 300 toes would cowl over 40 sq. miles inside a matter of minutes. In the meantime, the highest of Mount Katmai collapsed in on itself, forming a caldera.
Geological surveying carried out by the Nationwide Geographic Society over the following few years would reveal the volcano and the encompassing areas to be a lot modified. The adjoining Ukak river valley, as soon as lined with shrubland and tundra, was now utterly lined with pumice and ash, which shaped a large number of steam and gasoline producing vents (fumaroles) because it cooled. The world is now often called the Valley of Ten Thousand Smokes, and it was largely due to the efforts of people who found the function that Katmai was designated a nationwide monument in 1918.
One other well-known function of the park is the glacier that sits on the within wall of the caldera shaped by the collapse of Mount Katmai in 1912. Which means that the glacier is probably the one one on the planet to have a identified date of origin.
A Quick Historical past Of Brown Bears
The phrase “bear” comes from the previous English “bera”, which in flip, got here from the Proto-Germanic “bero” or brown one, which is believed to have been invented as a euphemism for the terrifying apex predators of historical Northern Europe, a prehistoric “he who should not be named”. Different northern European language teams went a barely totally different route with their re-naming of the iron age Voldemort, with Slavic languages adopting phrases that means “honey-eater”, and Baltic teams going with phrases that means “bushy” or “shaggy”.
The predecessor of the modern-day brown bear is mostly believed to be the Etruscan bear, or Ursus etruscus, which lived from round 5.3 million to 10, 000 years in the past, when it was worn out throughout the newest glacial interval. It might have been related in measurement and construct to the modern-day black bear and got here to be discovered all throughout Eurasia, and a few elements of North Africa.
The oldest identified brown bear fossil was present in China and is estimated to be roughly 0.5 million years previous, however it’s thought that the brown bear would have first developed round 800,000 years in the past earlier than spreading all through the Asian continent, reaching so far as Japan by 340, 000 years in the past.
Getting into Europe not lengthy after, roughly 0.25 million years in the past, the brown bear would probably have come into contact with its sister taxon the cave bear, which has additionally descended from the Etruscan bear a couple of tens of 1000’s of years earlier than.
Cave bear stays are quite common all throughout Europe. One collapse Austria (a part of the Drachenhohle caves) was even discovered to have the bones of over 30,000 people, which might have accrued over many centuries. With enamel tailored for consuming vegetation, the cave bear would have been not less than largely herbivorous however would have spent its summers placing on fats earlier than hibernating for the winter months when meals was scarce, very similar to the modern-day brown bear.
The species coexisted with brown bears in Europe for a number of 1000’s of years earlier than they lastly went extinct round 10,000 years in the past, and the precise cause for his or her disappearance is considerably of a thriller. Competitors for area with the brown bear would probably have performed a component, however cave work portraying the looking of cave bears by people level fingers at one other wrongdoer.
The motion of brown bears into the Americas is a bit more sophisticated. It’s thought that the primary brown bears in North America would have crossed the Bering land bridge (which might have stretched between Russia and Alaska in periods of low sea degree), earlier than 100,000 years in the past, nonetheless, it’s now broadly believed that it took a number of waves of migrations for the brown bear to colonise the North American continent.
The primary brown bears to look in North America have been roughly worn out previous to the newest ice age occasion, probably as a consequence of a interval of warming temperatures, which might have induced a change within the abundance of varied vegetation, and subsequently in prey animals. It wouldn’t be till the following glacial interval when sea ranges sank and the Bering land bridge was as soon as once more uncovered, that the brown bear would recolonise the continent, Probably alongside the primary people to settle in North America.
Brown bears are current all throughout the northern hemisphere at this time and are clever sufficient to determine a method to thrive even in our personal more and more urbanised environments, with one Yosemite forest ranger going so far as to state “there’s appreciable overlap between the intelligence of the neatest of bears and the dumbest vacationers” when questioned concerning the design of bear-proof bins.
The historical past of the brown bear is one which demonstrates how weak to alter our ecosystems might be, but in addition the immense potential for species to adapt to a altering world. what higher cause to rejoice the ecosystems that also thrive throughout our planet, and to guard them for future generations to get pleasure from?
Discover.org dwell bear cam (Brooks Falls)
Sophie Pollard is a present Masters pupil of the Palaeobiology course on the College of Bristol.
Edited by Rhys Charles