Today, we’re getting in the winter spirit by spotlighting five remarkable marine animals that depend on cold and icy environments to thrive.
1. Narwhals
Narwhals are often called the “unicorns of the sea” because of their long, spiraled tusk. Here are a few more fascinating facts about them:
- Believe it or not, their tusk is actually a tooth used for sensing their environment and sometimes for sparring.
- Narwhals are whales. While many whale species migrate south in the winter, narwhals spend their entire lives in the frigid waters of the circumpolar Arctic near Canada, Greenland and Russia.
- Sea ice provides narwhals with protection as they travel through unfamiliar waters.
2. Walruses
Walruses are another beloved Arctic species with remarkable adaptations for surviving the cold:
- Walruses stay warm with a thick layer of blubber that insulates their bodies from icy air and water.
- Walruses can slow their heart rate to conserve energy and withstand freezing temperatures both in and out of the water.
- Walruses use sea ice to rest between foraging dives. It also provides a vital and safe platform for mothers to nurse and care for their young.
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3. Polar Bears
Polar bears possess several unique traits that help them thrive in the icy Arctic:
- Although polar bear fur appears white, each hair is hollow and transparent, reflecting light much like ice.
- Beneath their thick coats, polar bears have black skin that absorbs heat from the sun. This helps keep polar bears warm in their icy habitat.
- Polar bears rely on sea ice platforms to access their primary prey, seals, which they hunt at breathing holes in the ice.
4. Penguins
Penguins are highly adapted swimmers that thrive in icy waters, but they are not Arctic animals:
- Penguins live exclusively in the Southern Hemisphere, mainly Antarctica, meaning they do not share the frigid northern waters with narwhals, walruses and polar bears.
- Penguins spend up to 75% of their lives in the water and are built for efficient aquatic movement.
- Sea ice provides a stable platform for nesting and incubation, particularly for species like the Emperor penguin, which relies on sea ice remaining intact until chicks are old enough to fledge.
5. Seals
Seals are a diverse group of carnivorous marine mammals found in both polar regions:
- There are 33 seal species worldwide, with some living in the Arctic and others in the Antarctic.
- There are two groups of seals: Phocidae (true seals) and Otariidae (sea lions and fur seals). The easiest way to tell seals and sea lions apart is by their ears: true seals have ear holes with no external flaps, while sea lions and fur seals have small external ear flaps.
- Seals need sea ice for critical life functions including pupping, nursing and resting. They also use ice for molting—a process in which they shed their fur in the late spring or early summer.
Defend the Central Arctic Ocean Action
Some of these cold-loving animals call the North Pole home, while others thrive in the polar south. No matter where they live, these marine marvels rely on sea ice for food, safety, movement and survival.
Unfortunately, a rapidly changing climate is putting critical polar ecosystems, like the Central Arctic Ocean, at risk. That is why Ocean Conservancy is fighting to protect the Central Arctic Ocean from threats like carbon shipping emissions, deep-sea mining and more. Take action now to help us defend the Central Arctic Ocean.
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The post 5 Animals That Need Sea Ice to Thrive appeared first on Ocean Conservancy.
Ocean Acidification
Dr Heidarzadeh’s TV interview with SkyNews on the massive M7.7 Panama earthquake on 9 October 2026
Dr Heidarzadeh’s TV interview with SkyNews on the massive M7.7 Panama earthquake on 9 October 2026. Click here for the full story.
Dr Heidarzadeh’s TV interview with SkyNews on the massive M7.7 Panama earthquake on 9 October 2026
Our ocean is an incredibly vast and mysterious place. And there is no place where that is more evident than the deepest ocean area in the world: the legendary Mariana Trench. Located east of the Philippines, the Mariana Trench lies in the Mariana Archipelago in the western portion of the North Pacific. The greater area of the Mariana Trench Marine National Monument is made up of more than 95,000 square miles of ocean. Beneath these waters lie incredibly complex aggregations of submerged islands and volcanoes … and of course, an astoundingly massive trench.
Dive in with us to have your biggest questions answered about the famed Mariana Trench.
How deep is the Mariana Trench?
The deepest part of the Mariana Trench, known as Challenger Deep, is almost 36,000 feet below the ocean’s surface. For context, Mount Everest is about 29,000 feet above sea level, so the Mariana Trench is about 7,000 feet deeper than Mount Everest is tall. For one more comparison, the RMS Titanic lies at a depth of about 12,500 feet below sea level. The Challenger Deep is in waters nearly three times deeper than this ship’s final resting place.
Due to its enormous size, the Mariana Trench has at times been affectionately nicknamed the Grand Canyon of the ocean. This is certainly a picturesque image, but don’t let the mammoth size of this U.S. national terrestrial park fool you into thinking the Mariana Trench matches its size. The trench’s footprint is estimated to be 120 times larger than the Grand Canyon’s, and to reach the bottom of Challenger Deep, you’d need to descend through almost six Grand Canyons stacked on top of each other before you’d reach the seafloor.
Oh … and did we mention it’s five times wider than it is deep? It’s about 43 miles wide!
What is Challenger Deep, and how long would it take to reach it?
Challenger Deep is the deepest point of the Mariana Trench. Fewer than 30 people have ever journeyed to this area. The trek below the surface is long, dark and time-consuming, and it’s not an expedition considered lightly by scientists and explorers.
The first people to descend into the depths of this area in 1960 were oceanographers Jacques Piccard and Don Walsh, and it took them close to five hours to reach Challenger Deep. Since then, more advanced submersibles have been created, but it still takes two to four hours for modern vessels to reach such depths. For example, explorer and filmmaker James Cameron reached the seafloor in a little more than 2.5 hours in the first documented solo submarine dive to the area, and it took oceanographer Dr. Dawn Wright about four hours in 2022. It is crucial that these submersibles descend slowly and steadily beneath the surface, as the immense water pressure compounds with every mile a submersible descends. Speaking of pressure …