Meet the master of camouflage, the day octopus

KOMODO NATIONAL PARK :: INDONESIA

Up close, the speckled skin of a day octopus (Octopus cyanea) looks a bit like a pointillist painting. But those spots are actually sacs of pigment under the cephalopod’s skin. By squeezing and contracting them, the octopus can intensify certain colors while muting others, mirroring surrounding hues or making itself stand out, depending on the situation. Like many other octopus and squid species, the day octopus (also called the big blue octopus for the blue circles in its skin) can also camouflage itself by changing its skin texture from smooth to bumpy to bizarrely spiky.

Day octopuses live in the Indian and Pacific Oceans, ranging from the warm waters of Hawaii to the coasts of eastern Africa. While they aren’t endangered, these masters of disguise are often found in coral reefs—and those reefs face steep challenges. According to a new report from the United Nations, if the world warms to 2°C (3.6°F) above preindustrial levels, coral reefs as we know them would largely disappear. Even if the global community can limit warming to 1.5°C (2.7°F), up to 70% of all reefs could be severely degraded by 2100—but that’s a far better outcome than the forecast for 2°C of warming.

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