Tony Wu / Humpback whale (Megaptera novaeangliae) adult female at rest. The tubercles on the whale's head are clearly visible, as are the barnacles (Coronula diadema), whale lice (Cyamus boopis), and hairs on t...

Tony Wu / Whale louse (Cyamus ovalis) on a Southern right whale (Eubalaena australis) South Africa. Photographed with the permission of the Department of Environmental Affairs, South Africa.

Tony Wu / Whale louse (Cyamus ovalis) on hand to show scale, came from a Southern right whale (Eubalaena australis) South Africa. Photographed with the permission of the Department of Environmental Affairs, Sou...

Tony Wu / Southern right whale (Eubalaena australis) inquisitive adult approaching to observe diver, note the callosity above the whales eye, which is populated by other organisms, including whale lice (Cyamus...

Tony Wu / Southern right whale (Eubalaena australis) at surface showing callosity on head with huge number of Whale lice (Cyamus ovalis) amongst other organisms, photographed with the permission of the Departme...

Tony Wu / Southern right whale (Eubalaena australis) calf resting its head on top of its mother, already with Whale lice (Cyamus ovalis) on its skin, photographed with the permission of the Department of Enviro...

Tony Wu / Southern right whale (Eubalaena australis) looking down on calf's head showing the development of callosities with whale lice (Cyamis ovalis) photographed with the permission of the Department of Envi...

Tony Wu / Researcher reaching over to take samples of Whale lice (Cyamus ovalis) from one of the callosities on Southern right whale (Eubalaena australis) at surface, photographed with the permission of the Dep...

Tony Wu / Humpback whale (Megaptera novaeangliae) close up of female with open nostrils surfacing to breathe, note the whale lice (Cyamus boopis) Vava'u, Tonga, South Pacific

Tony Wu / Humpback whale (Megaptera novaeangliae) calf with an infestation of whale lice (Cyamus boopis), an ectoparasite that lives exclusively on humpback whales, Vava'u, Tonga, South Pacific

Tony Wu / Southern Humpback whale (Megaptera novaeangliae australis) dorsal fin detail with Acorn barnacles (Coronula diadema) and whale lice (Cyamus boopis) visible, South Africa

Tony Wu / Whale lice (Cyamus scammoni) in the blowhole of a Grey whale calf (Eschrichtius robustus) Baja California, Mexico.