On October 9, Humboldt squid began washing ashore en masse along coastline in Monterey County, Calif.
Scientists had noticed such strandings in many squid species for decades, but why they happened was a mystery
While Humboldt squid (or jumbo squid) can reach 5 feet (1.5 meters) in length, the squid washing ashore in Monterey Bay are mostly juveniles about 1-foot (0.3 meters) long.
Researchers have noticed that schools of squid tend to beach en masse when they are invading a new territory, possibly because they get lost.
But during the most recent strandings, scientists noticed that the squid beached in 3-week cycles during red tides, or poisonous algal blooms
The algae release a toxic chemical called domoic acid, which causes brain cells to fire like crazy.
The timing of the red tides suggests that the squid may be intoxicated and disoriented by the neurotoxin.
These squid haven't been seen in the Monterey Bay for a few years, which means the current crop of squid beaching themselves are unfamiliar with the area.
Sometimes people will toss squid back into the water after a stranding, only to have them turn around and head right back for the beach, researchers say.
Beach strandings have occurred for decades and, though mysterious, probably aren't a sign of bigger problems in the environment, scientists say.
Here, marine biologist William Gilly holds a squid after a mass stranding
Humboldt squid usually live further south, off the coast of Baja California.