Science and the Sea Podcast

<p><img width="1500" height="1001" src="https://utmsi.utexas.edu/wp-content/uploads/2025/12/791125_Polar-Giants.jpg" class="attachment-post-thumbnail size-post-thumbnail wp-post-image" alt="image of Greenland shark" decoding="async" fetchpriority="high" srcset="https://utmsi.utexas.edu/wp-content/uploads/2025/12/791125_Polar-Giants.jpg 1500w, https://utmsi.utexas.edu/wp-content/uploads/2025/12/791125_Polar-Giants-300x200.jpg 300w, https://utmsi.utexas.edu/wp-content/uploads/2025/12/791125_Polar-Giants-1024x683.jpg 1024w, https://utmsi.utexas.edu/wp-content/uploads/2025/12/791125_Polar-Giants-768x513.jpg 768w" sizes="(max-width: 1500px) 100vw, 1500px" /></p> <p>The frigid waters of the Arctic and Antarctic hide some giants: sea spiders the size of serving trays, sharks as long as minibuses, half-ton squid twice that length—almost all of them the largest examples of their type anywhere on the planet.</p> <p>This phenomenon is known as polar gigantism. Biologists are still trying to explain it. In fact, they’re even trying to confirm that it’s a real thing; giants have been found in the deep ocean, and they may also inhabit other parts of the ocean, but we just haven’t seen them yet.</p> <p>There’s no doubt that giants inhabit the Arctic and Southern Oceans—the coldest waters of all. The list includes sponges, sea spiders, shellfish, tube worms, and others. Some of these creatures are many times the size and weight of most of their counterparts elsewhere. The colossal squid, for example, is not only the largest squid, but the largest invertebrate of any kind.</p> <p>Several explanations have been proposed for polar gigantism. The leading idea is the oxygen-temperature hypothesis. It says there’s more oxygen in colder waters, so there’s plenty to support larger organisms. And in the cold, the animals grow more slowly but they may live longer, allowing them to reach giant proportions. As an example, the Greenland shark, which can reach lengths of 24 feet, can live for centuries.           </p> <p>Not every type of polar marine animal is a giant—some are especially small. So scientists are still pondering what makes some of them the giants of the deep.</p> <p>The post <a href="https://utmsi.utexas.edu/science-and-the-sea/radio-program/polar-giants/">Polar Giants</a> appeared first on <a href="https://utmsi.utexas.edu">Marine Science Institute. The University of Texas at Austin.</a>.</p>