Did you know that the sea otter was nearly extinct a century ago? After decades of conservation, sea otters can finally survive. You may think that sea otters are cute, lovely, and innocent. In fact, sea otters are actually part of the carnivorous Mustelidae family. So, they are related to aggressive animals such as wolverines, skunks, and badgers.
Moreover, the sea otter is the smallest marine mammal in North America. Despite its size, this animal has various characteristics to survive. They have webbed feet, water-repellent fur, and nostrils and ears that seal in the water to keep them dry and warm. Sea otters also entangle themselves in kelp forests, or giant seaweed, near the water’s surface to keep them stay in place amid the rough sea waves.
Furthermore, sea otters are not just ordinary animals. But they are also smart and have an immense contribution to the environment. There are a lot of fun facts about sea otters that will make you admire this tiny animal more. If you are curious about it, let’s reveal them one by one!
1. Sea Otters Are Almost Extinct
Since it is mentioned that sea otters were almost extinct in the past, maybe you are curious about how many sea otters are left now. Sea otters have progressively rebounded worldwide, but their numbers are still much below what they were in the past.
With the signing of the International Fur Seal Treaty in 1911, sea otters were finally given protection after being hunted to near extinction in the 18th and 19th centuries. It is such a fun fact that we finally recognize the importance of sea otters’ existence!
They were given further protection in the 1970s under the Marine Mammal Protection Act and the Endangered Species Act. Historically, the Pacific Rim’s sea otters numbered between 150,000 and 300,000 animals. The southern sea otter population, formerly estimated to be over 16,000 animals, is now estimated to be only around 3,000.
2. Sea Otters Eat 25 Percent of Their Body Weight Every Day
Sea otters are also among the most ravenous animals. Even though mature sea otters weigh roughly 100 pounds, they require about 7,500 calories per day!
That amount of calories is insane because that is three times what an average human needs. This amount of energy is equivalent to 25% of their body weight in food. It is fun knowing the fact that sea otters eat so much!
Sea urchins, crabs, mussels, and clams are among the sea otters’ favorite foods, which they are known to crack open with a rock and consume while floating in the water. Sea otters hunt for food by diving as deep as 250 feet and using sensitive whiskers to discover small items inside fissures. They can also dig for clams with their muscular forepaws.
3. Sea Otters Have The Thickest Fur of Any Animal
Sea otters’ thick and fluffy fur is the central attraction of this animal. In fact, they have the densest fur among other animals. Each square inch of their fur contains 600,000 to 1,000,000 hair follicles.
Otters do not have a fat layer like most other marine mammals. Instead, they rely on their thick, water-resistant fur to keep warm. It is super fun knowing that sea otters are not fatty despite eating so much!
Moreover, sea otters spend a significant chunk of their days grooming and maintaining their fur to stay warm. This fur traps heat and air near their skin. This coat is priceless to otters, but it is also precious to some humans. In fact, sea otters have been hunted to near extinction for their thick fur.
4. Producing Energy without Significant Effort
You may know that fur keeps the sea otters’ bodies warm. However, the hair is not the only part that makes them survive living in the cold area. Their metabolic rate also plays a significant role. After all, they can produce high energy, nearly three times higher than most mammals of similar size.
In fact, the mitochondria in sea otter muscles may be extremely leaky, allowing otters to raise the temperature of their body without exerting physical effort or shivering. Sea otter muscle, it turns out, excels at being inefficient. Hence, they can endure the cold because of the energy “lost” as heat. The seemingly “flawed” cell is actually an advantage!
These fun facts about sea otters are astonishing, making us appreciate this species even more! It is mindblowing how their body is tailored for living in the cold sea.
5. Sea Otters Can Born Babies Anytime of The Year
Southern sea otters breed and have pups all year, whereas northern sea otter pups are generally born in the spring in Alaska. A newborn puppy needs continual attention and will remain with its mother for six months while learning to survive.
An otter pup’s fur is so dense that it prevents it from diving underwater until it grows into its adult fur. This will be beneficial for mothers to leave their puppies safely floating on the water’s surface while foraging for food. The fact that sea otters’ puppies can’t dive or drown is fun and comforting!
6. Domoic Acid That Causes Heart Disease
Southern sea otters that eat domoic acid in their diet are at risk of developing heart disease. Domoic acid is a neurotoxin that builds up in the food chain, contaminating crabs and clams, popular sea otter prey.
It is created by harmful algal blooms, which generally occur when water is warmer. A big warm water “blob” in 2015, for example, caused a broad toxic bloom along the West Coast. The event caused domoic acid levels to soar and prompted the closure of the Dungeness crab fishery for that season.
According to the researchers, domoic acid exposure boosted a sea otter’s chance of dying from heart disease by 1.7 times. The risk is up to 2.5 times higher for sea otters who consume a lot of crab and clam since they store domoic acid in their tissues, making it stay longer in the food chain.
Some of these facts may not be so fun for sea otters, but it is essential to understand them as humans. This way, we can help these cute animals more!
7. Otters Can Hold Their Breath for Up to 5 Minutes
The body of a sea otter is exceptionally buoyant. This is due to the air trapped in its fur and its bigger lung capacity. In fact, the Sea otter’s lung capacity is two and a half times larger than a similarly-sized land mammal’s capacity.
Sea otters have been reported to stay submerged for up to 5 minutes. On the other hand, River otters can hold their breath for up to 8 minutes. The longer time spent underwater allows otters to detect wildlife and seek food.
8. Sea Otters Eat Sea Urchins
Kelp forests often get decimated by sea urchins. Luckily, sea otters have a voracious appetite for sea urchins, so they help keep the urchin population in check. It allows the kelp to thrive and absorb CO2.
In fact, kelp may thrive and provide habitat for various ocean species. Usually, sea urchins hide in crevices and eat kelp scraps when sea otters are present. Therefore, sea otters may also be called keystone species as they balance the environment.
What makes it interesting, sea otters largely ignore sea urchins in the barrens, as they lack the nutritional value of those that have kelp to forage on. Moreover, when the urchins change their behavior to active foraging, the sea otters in the kelp forest select to feed on healthy urchins.
9. The Smart Mammals That Use Tools
Sea otters are rapidly climbing the ranks of intelligent marine mammals. Their capacity to open clams with rocks is unique among animals. According to a recent study, it’s also plausible that sea otters were the first species to utilize tools.
The tool of choice for a sea otter is usually a rock used as a hammer or anvil to crack open hard-shelled prey. They may also pound abalone shells with stones up to 45 times in 15 seconds to remove the abalone’s tight grasp on the bottom.
Have you ever wondered where sea otters hide their equipment for safekeeping? They have a loose skin beneath their armpit, where they store both the food and the rock they need to split open the food.
10. They Float and Hold Hands While Resting
Sea otters enjoy congregating in groups to rest. Over 1,000 otters have been sighted floating together, according to researchers. Sea otters float at the water’s surface by lying on their backs in a peaceful nap.
They appear silver underwater due to the oxygen in their fur. Sea otters will occasionally float in kelp forests or massive seaweed forests and wrap themselves in them to anchor themselves in choppy or fast-moving seas.
When sea otters sleep in the water, they also hold hands to avoid drifting apart and losing each other. Moreover, some sea otters hold hands since they fear losing their mate to another male while resting. As they float away from land, holding hands protects them from predators.
11. The Oldest Sea Otters
Did you know how long sea otters can live? In fact, sea otters can live up to 23 years in the wild. The males’ life spans from 10 to 15 years, while females’ lives span from 15 to 20 years.
Meet Yaku, the oldest sea otter who lives in Seattle Aquarium. This year, 2022, Yaku will turn 22 years old. Even though Yaku is considered elderly, he is in excellent health for his age.
According to animal experts, sea otters in their natural habitat can live into their late teens or early twenties. Only a few zoos or aquariums worked with sea otters until the late 1980s. Shedd Aquarium was one of the first to deal with and train sea otters.
12. Long Whiskers and Front Paws To Survive
As tiny creatures, you may wonder how sea otters survive in the wild. Sea otters have a variety of adaptations that aid them in staying in their harsh maritime environment.
Unlike other marine mammals, sea otters have long whiskers as thick as those of seals and sea lions. The animal also has front paws, which are significant parts that allow sea otters to survive in various conditions.
Researchers recently investigated how sea otters use their sense of touch to discriminate against objects. Long whiskers aid in detecting vibrations in murky waters, and sensitive forepaws with retractable claws aid in grooming, locating and capturing prey underwater. The claws also help the otters to use tools.
13. Sea Otters Spend Around 10 Hours Only to Find Food
Since otters eat a lot every day, they need enough food sources. Therefore, they spend almost a half day only foraging. Sea otters spend 1-2 hours less time foraging during the summer than during other seasons. They had high diurnal foraging preferences and modified their foraging effort according to the amount of daylight available.
After females give birth, they change their daily foraging habits. Females resorted to nighttime hunting for around 3 weeks after having a baby, probably to lessen the risk of eagle predation on newborn pups.
14. Toxoplasma Causes Sea Otters Mortality
Infection by land-based protozoan parasites like Toxoplasma and the related parasite Sarcocystis neurona are common causes of disease and mortality in southern sea otters. This data was collected in decades of detailed research by CDFW and UC Davis. They also used DNA tests to link Toxoplasma infection in otters to feline feces from upstream and wild mussels eaten by sea otters and humans.
In fact, these parasites can be found in cat feces. Suppose this parasite makes its way into the ocean. In that case, it can be highly hazardous to sea otters and other marine species, even fatal. Toxoplasma infections lead to the mortality of 8% of California sea otters. Moreover, it becomes the primary cause of death in 3% of those discovered dead.
15. Dirty Fur Can Cause Hypothermia
When a sea otter’s fur gets soiled, it has difficulty absorbing the air it needs to stay warm. Therefore, while they’re not feeding or sleeping, sea otters are compulsive about constantly keeping their fur clean and grooming themselves.
The undercoat of a sea otter is shorter than the upper guard coat. This second layer does an excellent job of retaining air and keeping water from coming into contact with the sea otter’s skin.
Hence, sea otters must keep their fur spotless to keep air confined, which means they must clean it regularly. Otherwise, even oil spills or dirt can harm sea otters more than other marine species. In fact, oil on their fur can cause hypothermia, leading to death.