So a while back I made this post
And it became very popular. While many people already knew, I did get some asking why humboldt squids are scary. So for this Wet Beast Wednesday I'm going to teach you why you should be afraid, or at least respectful, of molluscoid menace that is the humboldt squid.
(image: a humboldt squid)
Known to scientists as Dosidicus gigas and to many others as the jumbo squid, pota, jibia, and diablo rojo, the humboldt squid is the 5th largest squid in the world and the largest of the flying squids. Don't worry, it can't actually fly. They reach an average mantle length (tat's excluding the head and arms) of 1.5 meters, with some specimens reaching up to 2 meters (6.5 ft) in mantle length. The arms can reach up to another meter in length. Adults can weigh up to 50 kg (150 lbs), with females generally being larger than males. They live in the Pacific along the cost of the Americas, from the tip of South America up to California in North America. Some individuals have been known to travel farther north, up to Alaska, which is outside of their historical range. It is possible that as the ocean warms, their native range will continue to expand north.
(image: a humboldt squid releasing ink as a defense mechanism)
Humboldt squids reproduce in deep waters, and as a result we don't know much about their courtship. Males use a modified arm called the heterocotylus to transfer sperm into the female's mantle. She then lays a transparent, gelatinous egg mass that is left to float in the water column. These masses can range between 1 and 4 meters in diameter can can contain up to 4 million eggs. Hatchlings receive no parental care and most will die before adulthood. They grow extremely rapidly, likely as a self-defense against cannibalism by larger squids. Like many squid, humboldts only live for a year and die shortly after mating.
(image: a humboldt squid next to a much braver diver than I will ever be)
As with most cephalopods, the humboldt squid has cells called chromatophores that allow it to change color. Cameras attached to captured and released specimens have show two types of color-changing behavior: flashing and flickering. Flashing is when the animal changes rapidly between red and white. This is done in the presence of other squid and is likely a means of communication, possibly a form of courtship or warning to stay away. Flickering is when waves of red and white travel down the body. This is likely a form of camouflage to blend in with light flickering through the water. In addition to flashing and flickering, cameras have seen multiple forms of color changes and communication behaviors, indicating that they have a rich social life. The red color the squid turns when hunting contributes to its nickname amongst Mexican fishermen: "diablo rojo", the "red devil".
(gif: humboldts changing color)
So all that sounds pretty normal, why are they scary? Well that comes down to their feeding behavior and aggression. Humboldt squids hunt in shoals that can include thousands of members and go into feeding frenzies that can make shark feeding frenzies look like a child's tea party. They are infamous for their aggression and there are many stories of them attacking divers and fishermen. Not even they are immune to their predation, as multiple studies have found between a half and a quarter of all dissected specimens have recently fed on others of their species. Cannibalism may make up a major portion of their diet, though cannibalistic behavior seems to increase in response to stress. Their typical diet consists of fish, crustaceans, and other squids. Humboldts typically keep their two long tentacles coiled up between their arms, only for them to suddenly lash out and grab prey. These tentacles have multiple sharp hooks that have been reported to cause severe cuts in humans. Captured prey is then pulled in toward the beak and consumed. Feeding happens so fast that scientists need to us high-speed cameras to record the capture as the tentacles move so fast they prey can be caught and reeled in between frames. Eating is also fast enough that they can grab a hooked fish and skeletonize it in the time it takes a frustrated angler to pull their catch in. And if that wren't enough, they also engage in cooperative hunting, working together to catch prey. When not feeding or being hunted, they have been described as curious, though they often react to unfamiliar stimuli with aggression. Some divers have reported that humboldts will come investigate them and even act friendly, though I can't say I'd be willing to try it.
(gif: a squid attacking a camera)
(gif: hunting squid)
Numerous fishermen's tales and news stories tell of attacks on humans, but the squid do have a reason to not like us. They are fished heavily, especially off the coat of Mexico and are the most important squid for commercial fisheries. Humboldt squids make up about a third of all squid fished every year and are the most popular food squid. Squid meat is saturated with ammonium chloride, which they use for buoyancy, and must be prepared to remove the taste before eating. Not much is known about threats to conservation, though some speculate that overfishing and global warming disrupting their food supply could threaten the population. They are listed as data deficient by the IUCN. As scary as they might be, humboldt squids serve a very important ecological role in their territories, both as primary predators and as prey to sharks and toothed whales, and more research on their sustainability and conservation needs is important.
(image: a scientist attaching a crittercam to a humboldt squid)
