Marine Animals Are INFESTED With Lice, Barnacles, and Parasites!

Added: 2026-05-12

[00:00:00]I hate nasomites. Quick warning for all of my friends with entomophobia, arachnophobia, parasitic dermatophobia, or any kind of aversion to creepy crawies. Today we're talking about ocean parasites. I'm itchy just thinking about it. I'm KP, a marine biologist who has spent 15 years working with marine mammals like seals, sea lions, and citations. Because I specialize in marine mammals, I'm going to spend most of this video on their parasites. But I do want to give this evil creature a dishonorable mention. This is the aptly named tongue eating isopod. This insidious aberration crawls through the gills of a fish, cuts off the tongue, attaches to the nub where it feeds on the fish's blood while acting as the fish's artificial tongue. And I hate him.

[00:00:49]Luckily, marine mammals aren't afflicted by anything quite this vile. What they do have are lice. Most whales are absolutely crawling with lice. Every whale will have over 7,000 lice skittering across their skin. These kitenous critters prefer crevices, folds, and creases, which is why you mostly find them in the blow holes, around the eyes, in lesions, or on any rough patches of skin. If you look at a right whale, the distinctive bumps on their face are called colossities. These are hardened and rough patches of skin that are almost rocky and they're covered in barnacles, but their barnacles are dark like their skin. The white is all lice.

[00:01:33]The species of lice living on right whales are a completely different species than those crawling around humpback whales. Almost every species of whale is host to a unique species of lice. And there's a logical reason for this. Whales get lice from other whales.

[00:01:48]Calves get lice from their mothers during birth and nursing. Whales also spread lice when they rub against each other while mating, playing, or even fighting. Typically, whales don't rub against whales of other species. If humpback whales don't fraternize with right whales, they're not going to get right whale lice. Sperm whales have two unique species of lice that are sex specific. The reason is because male sperm whales spend most of their time in cold waters while females live most of their lives in warmer tropical waters where they give birth and raise their calves. So, one life species has evolved to survive in colder waters and only crawls on the males and the other species prefers warmer temperate waters and creeps on the females and the calves. Dolphins, which are tooththed whales, also have lice, but not nearly as bad, mostly because dolphins are generally faster and more acrobatic than baileing whales. So, the lice have a harder time clinging to their skin.

[00:02:44]Despite the name, whale lice are not lice. They're closely related to skeleton shrimp, and they're generally considered commensal, not harmful, because they clean algae and dead skin from the whales. But the same cannot be said for pinniped lice. They are a true louse that feeds on the blood of seals, sea lions, walruses, and surprisingly, river otter. Just like whale lice, many species of pineiped lice are unique to specific species of pineiped and for the same reason. Walruses don't socialize with seals just like blue whales don't hang out with right whales. Each species of pinniped lice has unique adaptations based on the adaptations of their host.

[00:03:26]Northern furs seals have the second densest coat in the world with about 300,000 to 350,000 hair fibers per square in. This fur is so dense, it's totally waterproof, trapping a layer of air against their skin and insulating them from the cold. This provides their lice with a dry, warm home where they never get wet. This species of lice couldn't live on walruses who have a very thin layer of fur but only in the summer. They completely shed their fur in the winter. And if you know why walruses only grow fur in the summer, let me know down in the comments. It's one of my favorite trivia questions about my favorite animal. The most extreme lice have to be the species that plague southern elephant seals. These seals are some of the deepest diving mammals in the world, routinely diving over 2,000 m or 6,600 ft deep. Because of this, southern elephant seal lice are evolved to withstand extreme hydrostatic pressure. During one experiment with a pressure chamber, an adult elephant seal louse was accidentally exposed to 450 kg per square centimeter for 7 minutes.

[00:04:32]This is the equivalent of a 4,500 m or 15,000 ft below the surface dive. That exceeds the deepest recorded dive of any marine mammal by over 1500 m. And the Laos survived.

[00:04:48]who's lousy now.

[00:04:52]Yes, sperm whale lice have also evolved to survive crushing depths. But remember, they're not a true louse.

[00:04:59]They're a crusty little shrimp that never leave the ocean. And the next evolution denier in my comments is going to get called a crusty little shrimp.

[00:05:07]Southern elephant seals will spend months at a time hauled out on land to breed and mol during the warm summers.

[00:05:13]So, their parasites have to survive both on land and in the water. These lice actually breathe better on land, and we honestly don't know how they obtain oxygen while underwater. The authors of this 2025 paper said, "It is hard to think of an organism that faces the extraordinary challenges of southern elephant seal lice." That is a a sentence I never expected to say. The evolution of pinniped lice is intimately associated with pinniped evolution. And one of the more surprising lines of evidence is the fact that river otter also carry pinipede lice. Seals, sea lions, and walruses share a common ancestor with otter, an aquatic animal with a long tail, doglike teeth, and webbed feet named puia. It looked and probably behaved much like a river otter with a body adapted for swimming even though it spent most of its time on land.

[00:06:08]Surprisingly, even though river otterters are host to pinipede lice, sea otterters are not. Instead, they have a completely different problem. Nasal mites. These ghastly monstrosities infect sea otter nasal passages causing inflammation, bone erosion, and bacterial infections. I hate nasal mites. Infested otter are 14 times more likely to have upper respiratory inflammation and it's far more common in older adults and those that have contact with harbor seals. Nasal mites are also more common in otter that have been rescued, rehabilitated, and released.

[00:06:44]Many of the sea otterters in Elhorn Slooh in Monterey Bay were at one point rescued and released. These sea otterters are almost five times as likely to have nasal mites than in other areas. Aggressively treating parasites is a major part of marine mammal rescue.

[00:06:59]That includes non-marine mammals like turtles. You've probably seen videos on social media of turtle rehab centers carefully scraping the barnacles off of rescued turtles. For the most part, turtle barnacles are harmless hitchhikers, but they can add weight and increase drag. This can impact a turtle's ability to swim, forage, and evade predators. These effects can stack. The slower the turtles swim, the more barnacles they accumulate. The more barnacles they accumulate, the slower the turtles swim. You get the idea. It's a vicious cycle. Sometimes these barnacles are actually secondary symptoms of illness or injury. A turtle that is sick or injured is going to swim slower than a healthy one, meaning they're going to accumulate more barnacles.

[00:07:41]But improper removal of barnacles will do more harm than good. Turtle shells are not just heavy armor. They are actually highly sensitive living structures containing nerves, blood vessels, and bone. Turtles can feel pressure and pain on their shells.

[00:08:00]That's why veterinarians and professionals at rescue centers will spend weeks painstakingly and carefully removing these barnacles one at a time.

[00:08:07]This should never be done by someone who is not a veterinarian or a trained professional at a certified rescue center. I also don't think people should be picking lice and barnacles off of whales. Whales have sensitive skin and picking off the barnacles has a potential to inflict pain.

[00:08:23]But it's also just a waste of time. Like I said, every whale can have around 7,500 lice crawling around on its skin.

[00:08:30]Picking off a dozen or two isn't going to make a difference. And whales are much larger and stronger than turtles, so the weight and drag they add isn't an issue. Whale barnacles die and shed naturally. Whales can also shake them off when they breach. Like whale lice, most species of barnacles attached to a unique species of whale. The barnacles on a grey whale are a completely different species than those on a grey whale. Nope, that's the same whale that I said twice and I meant to say two different ones. Pick two different whales. Two different species of barnacle. You get the idea. For the most part, barnacles are believed to be commensal. The barnacles get a free ride at no cost to the whale, but there is an argument for a symbiotic relationship.

[00:09:13]There are studies that have shown some whales may use barnacles as weapons or protective armor to add power to a strike in mating battles or in defensive battles against predators.

[00:09:25]It argues that most fight species have either colossities or incrustations of barnacles on their bodies which may serve as weapons or armor for defense.

[00:09:35]So whales like humpback whales that are more likely to engage and fight a predator like an orca will have a significantly greater number of barnacles than whales that are more likely to flee like blue whales and minky whales. If you want to learn more about how humpback whales defend seals and other animals from orca attacks, just check out my video right here. I promise it won't make you itch.