Animals Wildlife Meet the World’s Only Completely Freshwater Seal By Melissa Breyer Editorial Director Hunter College F.I.T., State University of New York Cornell University Melissa Breyer is Treehugger’s editorial director. She is a sustainability expert and author whose work has been published by the New York Times and National Geographic, among others. our editorial process Melissa Breyer Updated August 13, 2020 Olga Kamenskaya via bioGraphic Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species Russia's superlative Lake Baikal is home to the world’s only freshwater-exclusive seal. The Baikal seal is the only seal that lives exclusively in freshwater, and it's found nowhere else. And is it any wonder? If there is one body of freshwater where we'd expect to find completely unique creatures, I'd put my money on Lake Baikal. Situated in southeastern Siberia, at 25 million years of age it is the oldest lake in the world. Depths reach an astonishing 5,400 feet, making it the deepest lake on the planet – and it contains 20 percent of Earth’s total unfrozen freshwater reserve. Known as the "Galapagos of Russia," it is one of the most biodiverse places on the planet, due to its age and isolation – it has 1,340 animal species with 745 of them endemic, and 570 plant species,with 150 of them occurring only there. How a seal ended up in this giant icy wonderland is anyone's guess. One theory is that members of the species may have traveled up ice-choked rivers from the Arctic Ocean during the last ice age, notes the California Academy of Sciences magazine, bioGrahpic. These majestic ice seals use their claws to create breathing holes in ice that can be up to two meters thick. And while life in an icy lake might be tough, writes bioGraphic, "the greatest threat that Baikal seal populations face is pollution from factories situated along the lake’s shores." This is incredible image was taken by Olga Kamenskaya, an award winning photographer known for her nature and underwater photography.