Stomach-Churning Photos Show Half-Inch Whale Lice Feasting on Live Humpback

Lice the size of a human belly button have been pictured living on humpback whales in the waters off Australia.

Annika Dahlberg, who works at Blue Dolphin Marine Tours in Hervey Bay, Queensland, photographed the whales' parasitic passengers, as well as barnacles, on a mother and calf as they migrated south towards Antarctica for the Southern Hemisphere's summer months.

"It's difficult to say how many whales we see with the lice as you need a very close look, but we have seen them on multiple occasions over the season. We usually see the lice right at the front of the whale's face where they congregate," Dahlberg told Newsweek.

"A behavior common in Hervey Bay is known as 'mugging' and this is when the whales approach the boat and stay within close vicinity and often doing 'spyhops,' rising their heads out of the water to get a closer look at its surroundings," she said. "This is the perfect opportunity for a close look of the whale's face!"

Whales in general are an attractive host for parasitic species, with many species suffering from barnacles growing across their skin and sea lampreys harvesting blood with their sucker-like mouths.

Lice live on many species of whales, infesting skin folds like nostrils, genitals and eyes, with up to 7,500 individual lice living on a single whale. Most species of lice only live on one species of whale. The lice pictured have the scientific name Cyamus boopis, and live exclusively on humpback whales.

"We see the lice on both adults and its young, and most whales only have a small population living on them that are visible to us. The lice look extremely small when you see them but when you think about the whales being up to 15 meters [50 feet] in length, you realize that the lice are quite big. Many of the lice we see would be around 10 millimeters [0.4 inches]," Dahlberg said.

The lice live their whole lives on whales, never floating or swimming in the water column. They can be transferred between whales by touch, often during sex or fighting, and will also attempt to attach themselves to humans when handling whales.

"When you do get a very sick or injured humpback whale and its swimming slows down, that whale lice population explodes," tour boat operator Peter Lynch told ABC News Australia.

"We have seen unfortunately in the past, a very sick humpback come into the bay and it had a pink coloration appearance ... its entire body was covered in whale lice."

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The lice do provide some degree of benefit to their host whales, predominantly eating algae growing on the whale's skin. They also feed on flaking skin and wound sites, however, which can cause minor skin damage.

It is thought that some behaviors of the whales may be attempts to rid themselves of their unwelcome lodgers.

"If they're near the eye, near the blowhole openings—what might be considered more delicate parts of the body—that could be another reason for some of the splashing activities at the surface, maybe to try and dislodge the ones that are annoying them," Lynch said.