Are Barnacles on Whales Normal or Problematic? Or Both?

If you've ever seen images of baleen whales covered in little white bumps, you’ve probably wondered—what’s the deal with barnacles on whales? These crusty hitchhikers may look like pests, but they tell a fascinating story of marine life, symbiosis and survival.

Here’s how these barnacle clusters form, what they mean for whale skin, and why they’re so common on gentle giants like gray whales and humpback whales.

How Barnacles Attach to Whales

It all starts when barnacle larvae — tiny, free-floating plankton — come into contact with a whale's body. In particular, areas like the flippers, tail and head are ideal sites for attachment.

Once the young barnacles find a spot, they settle and form shells with wall plates that anchor into the whale's skin.

Unlike true parasites, barnacles don’t suck blood or tissue. They are filter feeders, grabbing food particles from the surrounding ocean as the whale swims. However, they can cause tissue damage in some cases, especially when barnacle clusters grow too large or detach.

Do Barnacles Live on Whales?

Yes! Whale barnacles, especially species like Tubicinella major, specialize in attaching only to cetacean hosts — specifically right whales. They're different from acorn barnacles or turtle barnacles, which prefer rocks, sea turtles, fish or even other whales.

Alongside barnacles, you’ll also find whale lice (tiny crustaceans that feed on the whale's skin and damaged tissue or barnacle scars). They’re often found clinging to similar areas on the whale's body — particularly around mother whales and calves, where the skin is more vulnerable.

Why Barnacles Are Important

barnacle-covered — Those little bumps on the whale tail? All barnacles. Paul Souders / Getty Images

Though barnacles may look uncomfortable, they don’t harm whales in the same way as true parasites. That said, the barnacles die if separated from their hosts.

They provide clues about the life and migration of individual whales, with each unique pattern of barnacle coverage helping researchers identify individual whales.

Interestingly, barnacle scars remain even after the creatures are gone, making it easier to recognize young whales as they grow. These scars are also seen in the fossil record, offering evidence that barnacles have been attaching to whales for millions of years.

Do Barnacles Serve a Purpose?

While they may not provide a clear benefit to whales, barnacles benefit from being constantly bathed in nutrient-rich water as filter feeding whales travel through the sea. This mobile buffet allows barnacles to thrive for the few weeks it takes them to mature.

In return, barnacles may act as minor armor against predators or other creatures, although this benefit to whales is still debated. What is clear is that these tiny creatures are a visible and enduring part of the whale's ocean journey.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.