Sign up for our mailing list! We also have t-shirts and mugs with our logo! Thanks to Richard from NC for his suggestion that leads us to learn about some interesting seals! Further reading: Mystery of Siberian freshwater seal food choice solved Under Antarctica's ice, Weddell seals produce ultrasonic vocalizations Further listening/watching: Rarely-heard Weddell Seal Sounds in Antarctica The bearded seal Wikipedia page with audio so you can listen over and over and over The Baikal seal, the world's only fully fresh water seal species: Baikal seal, round boi: The Baikal seal's teeth have teeth: A Weddell seal mama with her pup who seems to be practicing singing: Look ma, no ears! The bearded seal. Can you tell where its name comes from? (Moustachioed seal might be more accurate.) (Also, note the ear opening with no external ear flap.) Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week let’s learn about some interesting seals. Thanks to Richard from NC who suggested freshwater seals, which is where we’ll start. Most seals live on the coast and spend most of the time in the ocean. But there’s one species of seal that lives exclusively in fresh water. That’s the Baikal [bay-CALL] seal, and the only place it lives is a big lake in Siberia called Lake Baikal. Lake Baikal formed where two sections of the earth’s crust are being pulled apart by continental drift. That’s called a rift lake or rift valley lake. The lake gets bigger every year, but only by a tiny amount—just under an inch, or 2 cm. Since this has been going on for an estimated 25 to 30 million years, though, it’s an extremely big, deep lake. It is, in fact, the deepest lake on earth, and is also the oldest lake on earth. It’s more than twice as old as Lake Tanganyika in East Africa, which is also a large, deep rift lake but only about 12 million years old at the most. Lake Baikal is almost 400 miles long, or 636 km, and nearly 50 miles wide, or 80 km. At its deepest point, it’s 3,893 feet deep, or 1,186.5 meters. That’s from the surface of the water to the muddy bottom. But that mud and sediment on the bottom has been building up for a very long time and there’s a lot of it—4.3 miles of it, in fact, or 7 km. The water is very clear and very oxygenated, but the surface freezes for several months out of the year. Then again, there are some hydrothermal vents, especially in the deepest areas, that heat the water around them to 122 degrees Fahrenheit, or 50 Celsius. Because Lake Baikal is so deep, so big, so oxygenated, and so old, lots of species of animal live in and around it that live nowhere else in the world. That includes the Baikal seal. The Baikal seal is related to the Arctic ringed seal but has lived in the lake exclusively for probably two million years. It only grows five and a half feet long at most, or 1.65 meters, and is usually closer to four feet long, or 1.2 meters. It’s gray in color and has no external ears, so that its head appears smooth. It can still hear, but because it doesn’t have ears sticking out of its head, it’s more streamlined than seals with external ears. It has large eyes, a pair of front flippers that it uses to maneuver in the water and on land, and a pair of hind flippers that act like a tail instead of legs. That’s actually the main difference between earless and eared seals. Earless seals are more streamlined in general and more adapted for life in the water and for deep diving, but they’re awkward on land because they can’t use their hind limbs for walking. Eared seals have little flaps of external ears and while their hind flippers act as a tail in the water, the seal can turn its hind flippers over to walk on them on land. The Baikal seal is quite small for a seal, which keeps it from needing as much food as a bigger animal. For a long time people thought the Baikal seal mostly ate fish,