Today we're going to take a closer look at brains, how animals use them, and how some animals have even evolved to lose them! It turns out a brain (and intelligence more broadly) isn't easy to define, but what we do know for sure is that brains have evolved over time in response to the challenges in an animals' environment. And what we'll find is that sometimes it's much smarter to have a tiny, simple brain than a big, complicated one! 🦔🐒🐝🐛🐘🐍🐀🐠 🐢🐋🐅🦓🦇🦜🐜🪱🦑 🦀🐊 Learn more about Rae here! https://www.raewynngrant.com/​​ Watch our videos and review your learning with the Crash Course App! Download here for Apple Devices: https://apple.co/3d4eyZo Download here for Android Devices: https://bit.ly/2SrDulJ Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse Thanks to the following patrons for their generous monthly contributions that help keep Crash Course free for everyone forever: Alexis B, Rene Duedam, Burt Humburg, Aziz, Nick, DAVID MORTON HUDSON, Perry Joyce, Scott Harrison, Mark & Susan Billian, Junrong Eric Zhu, Alan Bridgeman, Jennifer Smith, Matt Curls, Tim Kwist, Jonathan Zbikowski, Jennifer Killen, Sarah & Nathan Catchings, Brandon Westmoreland, team dorsey, Trevin Beattie, Eric Koslow, Indika Siriwardena, Khaled El Shalakany, Shawn Arnold, Siobhán, Ken Penttinen, Nathan Taylor, William McGraw, Laura Damon, Andrei Krishkevich, Sam Ferguson, Eric Prestemon, Jirat, Brian Thomas Gossett, Wai Jack Sin, Ian Dundore, Jason A Saslow, Justin, Jessica Wode, Mark, Caleb Weeks __ Want to find Crash Course elsewhere on the internet? Facebook - http://www.facebook.com/YouTubeCrashCourse Twitter - http://www.twitter.com/TheCrashCourse Tumblr - http://thecrashcourse.tumblr.com/ Support Crash Course on Patreon: http://patreon.com/crashcourse CC Kids: null #CrashCourse #Zoology #PBSNature