Get your first KiwiCo box free by going to http://www.kiwico.com/minuteearth   Occasionally, internal or external factors change, allowing certain animals to become giant versions of themselves.   Thanks also to our supporters on ___________________________________________   To learn more, start your googling with these keywords: Spiracles: External respiratory openings on insects Carboniferous Period: The time period from 359-299 million years ago when the Earth’s oxygen levels increased rapidly. Square-Cube Law: A mathematical principle that describes the relationship between area and volume. Buoyancy: An upward force exerted by a fluid that opposes the weight of an immersed object. Phytoplankton: Microscopic plants eaten by krill and other zooplankton. Baleen: A filter-feeding system inside the mouth of some whales.   _________________________________________   Subscribe to MinuteEarth on YouTube: Support us on Patreon: And visit our website: https://www.minuteearth.com/   Say hello on Facebook: http://goo.gl/FpAvo6 And Twitter: http://goo.gl/Y1aWVC   And download our videos on itunes:  https://goo.gl/sfwS6n ___________________________________________   Credits (and Twitter handles): Script Writer: David Goldenberg (@dgoldenberg) Script Editor: Emily Elert (@eelert) Video Illustrator: Ever Salazar (@eversalazar) Video Director: Kate Yoshida (@KateYoshida) Video Narrator: Kate Yoshida (@KateYoshida) With Contributions From: Henry Reich, Alex Reich, Peter Reich Music by: Nathaniel Schroeder: ___________________________________________   References: Kaiser, A., et al. (2007). Increase in tracheal investment with beetle size supports hypothesis of oxygen limitation on insect gigantism. 13198-13203. PNAS. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1941816/   Sander, P. Christian, et al. (2011). Biology of the sauropod dinosaurs:the evolution of gigantism. Biological Reviews. 86(1): 117–155. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3045712/   Taylor, M and Weder, M. (2013). Why sauropods had long necks; and why giraffes have short necks. PeerJ 1:e36. Retrieved from: https://arxiv.org/pdf/1209.5439.pdf.   Verberk, W. and Bilton, D. (2011). Can Oxygen Set Thermal Limits in an Insect and Drive Gigantism? PLOS One. 6(7): e22610. Retrieved from: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0022610   Slater, G., Goldbogen, J., Pyenson, N. (2017). Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics. Proceedings of the Royal Society B. 284: 20170546. Retrieved from: http://rspb.royalsocietypublishing.org/content/284/1855/20170546.