Summary: <p>This week’s episode is about some interesting eels, including the Brantevik eel.</p> <p>A European eel:</p> <p><img class="alignnone size-medium wp-image-435" src="http://strangeanimalspodcast.com/wp-content/uploads/2018/01/ollietheeel-300x165.png" alt="" width="300" height="165"></p> <p>A leptocephalus, aka an eel larva:</p> <p><img class="alignnone size-medium wp-image-438" src="http://strangeanimalspodcast.com/wp-content/uploads/2018/01/leptocephalus-300x200.jpeg" alt="" width="300" height="200"></p> <p>A moray eel. It has those jaws you can see and another set of jaws in its throat:</p> <p><img class="alignnone size-medium wp-image-437" src="http://strangeanimalspodcast.com/wp-content/uploads/2018/01/56666_massive-jaws_jfxeaqbh63vorhnrwcs4oomcjs2ptt7hevj74cagwi5qbj2htjuq_757x567-300x225.jpg" alt="" width="300" height="225"></p> <p><strong>Episode transcript:</strong></p> <p>Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.</p> <p>This week, we’re going to learn about the Brantevik eel and some other eels, including an eel mystery.</p> <p>The Brantevik eel is an individual European eel, not a separate species. Its friends knew it as Åle, which I’ve probably misprounounced, so I’m nicknaming it Ollie. So what’s so interesting about Ollie the eel?</p> <p>First, let’s learn a little bit about the European eel in general to give some background. It’s endangered these days due to overfishing, pollution, and other factors, but it used to be incredibly common. It lives throughout Europe, from the Mediterranean to Iceland, and has been a popular food for centuries.</p> <p>The European eel hatches in the ocean into a larval stage that looks sort of like a transparent flat tadpole, shaped roughly like a leaf. Over the next six months to three years, the larvae swim through the ocean currents, closer and closer to Europe, feeding on microscopic jellyfish and plankton. Toward the end of this journey, they grow into their next phase, where they resemble eels instead of tadpoles, but are mostly transparent. They’re called glass eels at this point. The glass eels make their way into rivers and other estuaries and slowly migrate upstream. Once a glass eel is in a good environment it metamorphoses again into an elver, which is basically a small eel. As it grows it gains more pigment until it’s called a yellow eel. Over the next decade or two it grows and matures, until it reaches its adult length—anywhere from two to five feet, or 60 cm to 1.5 meters. When it’s fully mature, its belly turns white and its sides silver, which is why it’s called a silver eel at this stage. Silver eels migrate more than 4,000 miles, or 6500 km, back to the Sargasso Sea to spawn, lay eggs, and die.</p> <p>One interesting thing about the European eel is that during a lot of its life, it has no gender. Its gender is determined only when it grows into a yellow eel, and then it’s mostly determined by environmental factors, not genetics.</p> <p>Until the late 19<sup>th</sup> century, everyone thought these different stages—larva, glass eel, elver, yellow eel, and silver eel—were all separate animals. No one knew how or even if eels reproduced. The ancie</p>
