How did a seal get to a lake in the middle of Siberia

the baikal seal or the nerpa as it's known in russian is the only freshwater species of seal in the world with its entire population being contained within one lake lake by cow in siberia the reason that an entire population of seal species can hunt breed and live their whole lives in one lake is that lake by cow is absolutely massive having a larger area than the whole of belgium being one of the largest lakes in the world so there is plenty of room however what isn't known is how they got there in the first place as the lake is more than 1500 kilometers and a mountain range away from the nearest sea while the lake itself is over 450 meters above sea level so how did they get there the baikal seal may be the only freshwater species of seal in the world but it is not the only seal that is isolated in a landlocked body of water as the caspian seal a close relative of the bicow seal is also not able to access any of the other oceans their whole population being contained within the caspian sea and the way in which both of these seals got to where they are maybe from the same reason there are two main theories that explain how the seals got to their current habitats one being that they were able to travel across northern russia due to flooding that was caused by the many galacias that formed during the ice age about a hundred thousand years ago and some seals are known to do this traveling over land into lakes but only when they are very close to the ocean so when there was extensive glaciation all over russia in the ice age it may have been possible for them to pass into the caspian sea and lake baikal from the north and this is backed up by dna evidence because the closest relative of the caspian seal and the by cows seals are ringed seals the most common species of seal found in the arctic ocean the other theory is that about five to ten million years ago in a time known as the mayo scene the caspian and the black sea were combined together into one giant inland ocean called the paratethys sea that flooded much further than their modern coastlines and this ocean may have had some sort of corridor connecting it to the other oceans when the paratethys disappeared the caspian seal and the baikal seal could have been separated and trapped in their current habitats allowing them to become two different species over time and there is evidence that this could have happened because the region around where this old sea would have been has bones from long dead seals however the problem is that the seals may not be old enough for this to have happened seals evolved from otter looking animals that were closely related to bears called cementaries and the earliest fossils of these creatures are known from northern canada around 21 to 24 million years ago so seals would have been around when this ocean existed but the baikal seals were much younger than this the baikal seal's closest relatives are the ringed seal and the caspian seal with most dna evidence pointing to them separating about two to three million years ago but the paratethys sea would have long disappeared by this point so the dates don't quite add up and so although there are some good ideas to how the seals became landlocked there are still things that need to be worked out and so it is still a bit of a mystery the seal may be one of lake macau's most charming residents but the lake itself is very unusual too being a bit of a geological phenomenon the lake is ancient being the oldest lake in the world at 25 million years old which is spectacularly old for a lake that unlike mountains or volcanoes often aren't actually that old and can form and then dry up within thousands of years rather than millions although at the time of its formation it probably looked quite different to how it does today in fact it was most likely a group of lakes rather than just one but over time it took shape with the lake joining up creating the behemoth that exists today the lake's strange geography has led to the evolution of many unusual species that live alongside the baikal seal because lake baikal is landlocked and has been for a very long time its ecosystem is very isolated so animals have been able to evolve independently from other bodies of water it is basically the reverse of islands like the galapagos islands or madagascar that have very unique ecosystems due to being separated from the mainland this is given lake by cow the nickname the galapagos of russia although the galapagos islands formed about three to five million years ago so lake by cow is actually even older and so its ecosystem has been isolated for even longer lake baikal supports over 1500 species of animal and over a thousand species of plants and at least half of them aren't found anywhere else however it isn't just the isolation of the lake that encourages such a large and diverse ecosystem containing thousands of species lake baikal is one of the largest lakes in the world but what really sets it apart is how deep the lake is as it's the deepest lake in the world and there are not many other lakes that even come close lake baikal is deeper than the caspian sea by a fairly large margin and almost three times as deep as the deepest lake in the us lake baikal is so deep because it is in a valley formed by the earth's surface being pulled apart in an area of the world that has a weakened crust specifically lake baikal is in between two geological structures known as the siberian platform and the north china plate which are basically ancient continents that are no longer independent the reason why this is important is because different creatures have evolved to live at different depths driving diversity the ocean is divided into different zones organized by the amount of light that can penetrate into the sea at different depths and different creatures are found in the different zones that have evolved depending on the pressures and requirements of living in each zone for instance swordfish have incredibly large eyes to help them see deeper in the ocean however far below swordfish so little light cuts through the depth that creatures have had to evolve ways of sensing their environment without eyes or have to make their own light lake baikal is nowhere near as deep as the deepest parts of the ocean but it is deep enough to stretch across multiple zones and this is made some fish that live in lake baikal evolve in a similar way to deep sea fish and the similarities don't stop there as lake by cow even has thermal vents on its lake bed similar to the deep sea being the only body of fresh water known to have them in the world similar to island ecosystems the sizes of some of the animals found in the lake are augmented from their relatives in other parts of the world for instance lake baikal has many species of a type of crustacean called an amphipod that are found both in freshwater and seawater anthropods found in other freshwater ecosystems around the world are usually no larger than two centimeters or so and quite often can be a lot smaller but in lake by cow there are species of anthropods that can grow to over seven centimeters long island gigantism and dwarfism are often caused by differences in the availability of food or threat levels from predators in the isolated ecosystems from the main one and this seems to have had an effect on the bi-cow seal as well dna evidence shows the nurpa are most closely related to ring seals but in average by cal seal are about 20 centimeters shorter most likely due to the lake's isolation so lake baikal is a lake but it acts like a small ocean and its strange properties have made it develop a truly unique and fascinating ecosystem even if how the bike house seal or the nerpa found itself marooned in an incredibly remote part of siberia may still be a bit of a mystery thank you for watching a big thank you goes to all my patrons especially the big contributors that are listed here if you 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Channel: Moth Light Media

Views: 914,970

Keywords: baikal seal, seal, sea monster, giant crustacean, evolution, ecology, russia, siberia, cool animals, lake baikal, middle of russia, deepest lake in the world, oldest lake in the world

Id: 7GUnQsnLVGo

Length: 8min 1sec (481 seconds)

Published: Thu Nov 11 2021