For the first time ever, scientists have recorded footage of Humboldt squids (aka jumbo squids) "lighting up like Christmas trees," as they flash and flare using their built-in lights. Though scientists have seen this behavior before while diving, it's exciting to see natural squid behavior without the interference of humans.
Squids can flash and flare their skin using chromatophores - light reflecting cells. By changing the intensity and rate of the flashing, it's believed that squids can communicate with one another. When a squid opens its arms wide and flashes from red to white, it could be trying to intimidate rivals or attracting a potential mate.
To catch the squids, scientists donned wetsuits and dove into the water with the beasts after luring them to the surface with chum. Jumping into the water with a seven foot Humboldt squid is no easy feat. These cephalopods are down-right nasty - aggressive and territorial; each sucker surrounds a ring of barbed teeth.
Once in the water, herpetologist Brady Barr and colleagues secured a CritterCam on a synthetic sleeve around the squid's mantle. The first sleeve was a disaster - flashing red LED lights on the camera attracted the attention of aggressive Humboldts, which ripped it off of the other squid. The next CritterCam deployments fared better, and the team received footage of flashy displays between the squids.
On this same expedition, the team measured the strength of a Humboldt squid's bite. Squids have a strong chitinous beak nestled in between their circle of arms and tentacles. Let's put it this way: You don't want to get in between a squid and its meal. While they were attaching CritterCams to Humboldts, the team also measured the strength of the squid's bite. According to the team, the squid bit through two plates of Kevlar - which is about 20 times stronger than steel. "I am pretty sure a large squid could bite well into a human arm,-" explains Roger Hanlon, a senior scientist at the Marine Biological Laboratory in Woods Hole, "and perhaps even through the bone." As a reference, the bite readings show that the squid had a bite force of more 1000 pounds - stronger than a hyena, but less than a crocodile's bite.
Source: National Geographic