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Why Don’t Orcas Have Barnacles?

Have you ever wondered why you don’t see barnacles stuck to orcas (killer whales) like you do on humpback whales? It’s an interesting question with a few possible explanations. In this blog post, we’ll dive into the details and explore some leading theories on why orcas don’t have barnacles. 

Why Don’t Orcas Have Barnacles?

Why don't orcas have barnacles?

There are a few key reasons why orcas don’t tend to have barnacles on their skin:

Orcas Move Fast

One major factor is that orcas are very fast swimmers. They can reach speeds up to 30 mph when hunting prey. This high speed allows them to slough off any barnacles that try to attach to their skin before they can take hold. Like how driving fast on the freeway prevents bugs from splattering on your windshield. 

Barnacles prefer to attach to slow-moving animals like humpback and grey whales. These whales only reach 5-12 mph speeds, allowing barnacles time to cement themselves to the whale’s skin. So, the orca’s high-speed lifestyle helps prevent barnacle buildup.

Orcas Shed Their Skin

Orcas also undergo an annual moulting process where they shed and replace their outer skin layer. This helps remove dead skin cells, parasites, algae, or barnacles that may have tried to attach to their body. 

During the moulting period, you can often see white flakes or sheets of skin peeling off of orcas. Removing this outer layer gives their skin a fresh start and removes anything that may have built up.

Streamlined Bodies

An orca’s streamlined, torpedo-shaped body is not very conducive to barnacle attachment. Barnacles prefer to latch onto irregular surfaces that are easier to grip. 

For example, the bumps, crevices, and ridges on a humpback whale’s flippers and tail flukes provide good holding spots. In contrast, the orca’s smooth skin gives barnacles nowhere to grab onto.

Constant Movement

Orcas are also constantly on the move, unlike baleen whales that migrate long distances. Baleen whales and humpbacks will stop to rest and mate in warm breeding grounds with abundant barnacles. This gives barnacles plenty of time to attach. 

Meanwhile, orcas are always swimming, hunting, and travelling in pods. They even rest by taking turns napping while other pod members swim. This constant activity and motion make it hard for barnacles to cement themselves.

No Migration to Warm Waters

The waters that orcas live in also make a difference. Humpback whales migrate from cold feeding areas to warm tropical breeding grounds. 

Warm waters like those around Hawaii and the Caribbean have an abundance of barnacle larvae. So humpbacks pick up most of their barnacle hitchhikers in these lower latitude breeding areas.

Alternatively, orcas stick to cooler waters near Antarctica and the Pacific Northwest. The frigid waters they call home have far fewer barnacle larvae, giving orcas less exposure.

Keen Senses

Some experts believe orcas may be able to sense when barnacles try to attach to their skin. Using their keen sense of touch, they could then rub against rocks to scrape off any unwanted squatters.

We know whales regularly rub their bodies along the seafloor, but scientists aren’t sure if they do this intentionally to remove barnacles. It’s an interesting theory, though!

Pod Hygiene

Killer whale pods also practice communal hygiene by rubbing and scratching each other’s skin. This social grooming behaviour could help them remove any barnacles or parasites their pod mates can’t reach on their own. 

Working together to stay clean would be very beneficial in the bacteria-filled ocean. Plus, we know orcas are highly intelligent and social animals that care for one another.

How Do Barnacles Attach to Whales?

To fully understand why orcas don’t pick up a lot of barnacles, it helps to know how these little crustaceans hitch a ride on marine mammals in the first place. Here’s a quick rundown:

  • Barnacles start off as tiny free-floating larvae after hatching from eggs. They drift along in the ocean currents until they grow and mature.
  • When ready to settle down, the barnacle larvae latch onto a passing whale using sticky threads. They prefer to attach to areas with ridges, bumps, or grooves that provide a good grip.
  • After cementing themselves to the whale’s skin, the barnacles grow a hard, protective shell. They’ll remain stuck to the whale for life. 
  • As the whale swims, the barnacles filter tiny food particles like plankton out of the passing water to eat. So they get a free buffet.
  • Whales visiting warm tropical waters tend to pick up the most barnacles. Waters around Hawaii have huge amounts of barnacle larvae ready to hitch a free ride. 
  • Slow-moving baleen whales like humpbacks provide the ideal mobile habitat for barnacles to thrive on. This allows large colonies to build up over time.
  • Eventually, the dead barnacles slough off the whale during the annual migration and moulting cycles. But new larvae quickly take their place in the breeding grounds.

So, in summary, barnacles love attaching to slow, irregularly shaped whales that frequent warm tropical waters. Orcas avoid picking up barnacles by staying in cold northern waters, constantly shedding skin, and doing communal grooming.

Are There Any Orcas With Barnacles?

While it’s extremely rare, a few orcas have been spotted with some barnacle growth over the years. In 2005, marine biologists saw a juvenile male orca named L98 off the coast of Vancouver Island covered in a light smattering of barnacles. 

Researchers weren’t sure why L98 had barnacles when the rest of his pod did not. He might have been separated from his pod and couldn’t participate in their communal skin care. He may have also been in slightly warmer waters that encouraged barnacle growth.

The barnacles fell off L98 within a few months during his annual moulting cycle. So, even orcas that pick up temporary barnacle patches can easily slough them off. 

A juvenile orca with barnacles was also spotted off the coast of Russia in 2015. And remoras, which are related to sharksuckers, have occasionally been documented sticking to orcas. But in general, spotting an orca with any external organisms is extremely uncommon.

Can Orcas Remove Barnacles? 

Even if a few barnacle larvae do manage to hitch a ride, orcas have ways to remove them:

  • Orcas can rub their bodies along abrasive surfaces like sand, gravel, or rocks to scrape off any external attachments.
  • Orcas may be able to sense when something starts growing on their skin and target that spot for extra rubbing and scrubbing.
  • Pod members will use their teeth to scrape and scratch each other’s skin. This social grooming can dislodge any unwelcome barnacle squatters.
  • High swimming speeds generate force that can rip off new growths before fully attaching.  
  • The cold northern waters orcas inhabit slow barnacle growth, limiting their reproduction/spreading.

So, between speed, moulting, rubbing, social grooming, and living in cold water, orcas have the barnacle issue under control. If one does manage to attach, they have ways to remove it quickly.

Why Do Other Whales Have Barnacles?

In contrast to orcas, many baleen whale species can get covered in hundreds or even thousands of barnacles. Here’s why humpbacks, grey whales, right whales and others end up with so many:

  • They migrate slowly from cold feeding grounds to warm tropical waters. The warm seas contain abundant barnacle larvae ready to hitch a ride.
  • Baleen whales have irregular, bumpy skin with grooves that barnacles can easily latch onto. Orcas have smooth, streamlined bodies.
  • Their swimming speed tops around 10 mph, allowing barnacles time to cement. Orcas swim over 30 mph.
  • Long rest periods in breeding grounds give barnacles uninterrupted time to attach and spread. Orcas are constantly active.
  • Baleen whales don’t shed their skin as often as orcas. A moulting orca removes any barnacle buildup.
  • The bodies of baleen whales like humpbacks, are ideal habitats, essentially serving as floating reefs.

So, baleen whales present the perfect target for barnacle infestation. Their migration patterns, skin texture, rest periods, and limited moulting allow the crustaceans to thrive. Orcas avoid these issues with speed, shedding and their cold water lifestyles.

Can Barnacles Harm Whales?

Aside from creating some drag while swimming, barnacles don’t typically bother most whales too much. The benefits likely outweigh any minor annoyances.

Some potential pros and cons of barnacles for whales:


  • Barnacles may protect whales’ skin from UV damage or abrasions from sand/rocks. It’s almost like wearing natural protective armour.
  • Gooseneck barnacles extending from the body may deter parasites or predators.
  • Whales may communicate using the sounds of barnacles opening and closing their shells.
  • Barnacles could potentially remove dead skin cells and detritus during attachment. This “exfoliating” may promote skin health.


  • Large colonies increase drag while swimming, wasting small amounts of energy. But whales are so big they barely notice.
  • Heavy barnacle cover could mildly impede thermoregulation by blocking heat exchange.
  • Some whales may try to rub off excessive barnacle buildup if it gets uncomfortable. But most seem content.
  • Dead barnacles falling off in sheets may temporarily expose raw skin until the next moulting cycle.