Most fish are pretty sluggish in the cold. But the Pacific bluefin tuna is one of the fastest apex predators in the frigid Pacific ocean. Their physiology has adapted to help them retain more of the heat their bodies produce, except when it comes to their cold, cold hearts. Hosted by: Rose Bear Don't Walk SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at http://www.scishowtangents.org/ ---------- Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow ---------- Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever: Chris Peters, Matt Curls, Kevin Bealer, Jeffrey Mckishen, Jacob, Christopher R Boucher, Nazara, charles george, Christoph Schwanke, Ash, Silas Emrys, KatieMarie Magnone, Eric Jensen, Adam Brainard, Piya Shedden, Alex Hackman, James Knight, GrowingViolet, Sam Lutfi, Alisa Sherbow, Jason A Saslow, Dr. Melvin Sanicas ---------- Looking for SciShow elsewhere on the internet? Facebook: http://www.facebook.com/scishow Twitter: http://www.twitter.com/scishow Tumblr: http://scishow.tumblr.com/ Instagram: http://instagram.com/thescishow ---------- Sources: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5332387/ https://www.sciencedirect.com/science/article/pii/B9780123847195001489?via%3Dihub https://pubmed.ncbi.nlm.nih.gov/20667881/ https://www.pnas.org/content/112/27/8350 https://pubmed.ncbi.nlm.nih.gov/9359368/ https://pubmed.ncbi.nlm.nih.gov/25540278/ https://link.springer.com/article/10.1007/s10641-008-9409-8 https://link.springer.com/article/10.1007/s10695-006-9104-7 https://journals.biologists.com/jeb/article/210/23/4254/17208/Temperature-effects-on-metabolic-rate-of-juvenile https://www.int-res.com/articles/meps2008/356/m356p239.pdf https://islandscholar.ca/islandora/object/ir%3A1058/datastream/PDF/view https://www.sciencedirect.com/science/article/abs/pii/S0079661117300988 https://www.int-res.com/articles/meps2008/356/m356p239.pdf https://www.sciencedaily.com/releases/2015/02/150205083040.htm https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-currents Images: https://commons.wikimedia.org/wiki/File:Pacific_bluefin_tuna.jpg https://commons.wikimedia.org/wiki/File:Thunnus_orientalis_(Osaka_Kaiyukan_Aquarium).jpg https://www.storyblocks.com/video/stock/school-of-fish-sharks-swim-in-a-circle-bxmooud427jnu9515v https://www.storyblocks.com/video/stock/shoal-of-jack-fish-in-tulemben-in-bali-indonesia-mcuixdu https://commons.wikimedia.org/wiki/File:Thunnus_orientalis.jpg https://commons.wikimedia.org/wiki/File:Circulus_arteriosus_schaf.jpg https://commons.wikimedia.org/wiki/File:Laika_ac_Tuna_Tank_(7472071434).jpg https://www.storyblocks.com/video/stock/a-view-up-to-the-ocean-surface-from-deep-underwater-hh7rfzgp8k8ha2v7f