Monster Monday: Red Devils of the Deep
December 21, 2015
The notorious Humboldt squid (Dosidicus gigas) is known as “el diablo rojo” (the red devil) among fishermen on the Pacific Ocean from Mexico to South America. The fiercest of all squids, when they are angered, these modern-day sea monsters flash a deep red color that comes from light-emitting structures called photophores in their skin. Humboldt squids are said to be particularly dangerous to divers, because the large animals aggressively attack anything in the water. Divers have reported lucky escapes after being suddenly swarmed by the ferocious creatures, receiving painful cuts from the squids’ hooked tentacles as they are engulfed and dragged into the inky depths.
Humboldt squids are common in the waters of the Pacific from northern Mexico to the islands of Tierra del Fuego, at the southern tip of South America. The squids are named after the Humboldt Current, also known as the Peru Current, a wide band of cool water that flows slowly north along the west coast of South America. They spend most of their time in the deep ocean at depths from 600 feet (183 meters) to 3,000 feet (915 meters), but they come up to the ocean surface to hunt at night.
The squids—up to 6 feet (2 meters) in length—hunt in shoals of more than 1,000 animals and pounce upon any prey that appears vulnerable. They normally feed on fish and shrimp-like krill. But they have also been observed attacking larger prey, including sharks, marine mammals, and even a submarine. Scientists think these marine animals may sometimes hunt cooperatively. When a Humboldt squid seizes a victim in its tentacles, other squids will quickly attack, tearing off chunks of flesh with their powerful parrot-like beak. These squids are also notorious cannibals. A Humboldt squid caught on a hook is often quickly consumed by its ravenous brethren before it can be hauled aboard.
Humboldt squids reproduce in the warm waters off the coast of northern Mexico in the winter. Every so often, they migrate farther north, sometimes as far as the Gulf of Alaska in the United States. Frightening episodes of Humboldt squid invasions in northern California waters have been recorded since the late 1800’s. In the 1930’s, fishermen in Monterey Bay complained that the aggressive squids kept eating their catches right off the line. Scientists observe that Humboldt squids often migrate farther north in years when El Niño, a periodic warm water current that develops in the Pacific Ocean, occurs. With a strong El Niño developing in the Pacific in late 2015, scientists are curious to see if the red devils’ return will once again menace the shores of California.