It’s our 100th episode! And to celebrate our migration from double- to triple-digits, we’re talking about… animal migration... Ok, we forgot it was our 100th episode. But this is still a great episode! Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions!  While you're at it, check out the Tangents crew on Twitter: Stefan: @itsmestefanchin Ceri: @ceriley Sam: @slamschultz Hank: @hankgreen If you want to learn more about any of our main topics, check out SciShowTangents.org!