Scientists spot a squid doing something profoundly rare in the deep sea

Marine researchers had a strange encounter during a recent dive in California's Monterey Bay. A squid mom hauled a spawling sheet of eggs through the water. 

"During a recent deep-sea dive, MBARI researchers encountered this incredibly rare sight — a deep-sea squid (Bathyteuthis sp.) grasping hundreds of eggs in her arms," the Monterey Bay Aquarium Research Institute (MBARI) tweeted. Their remote-operated vehicle captured this squid behavior at around 4,500 feet beneath surface.  

Squids are generally thought to lay their eggs, leave them to develop on their own, and then swim away. So carrying hundreds of potential offspring is quite unusual to see. 

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Parental instinct gives the best answer for this behavior, Stephanie Bush, a marine scientist at the Smithsonian National Museum of Natural History, told Mashable. "The squid is protecting the eggs against predators," Bush, who was not part of the dive, said. This squid could have perceived the noisy robotic vehicle as a threat, and promptly fled with the eggs when the vehicle traveled close by.

Since squids live in the deep oceans, we tend to think of them as fairly slow-moving (to conserve energy in nutritionally-limited dark waters, deep sea creatures move slowly). "But if you get too close, they can actually get off pretty quickly," Bush explained.

There is also a secondary reason for this peculiar behavior, Bush added. Water temperature is crucial for egg development, and the temperature varies at different depths in the oceans. So female squids sometimes carry their eggs to ensure they're exposed to optimal temperatures.

Marine biologists call this "brooding," wherein mothers watch over their eggs until they hatch. Only a handful of known squid species carry eggs along with them. Female squids are more likely to show this egg-grasping behavior than males. Also, when there is no place in the open ocean for the eggs to attach and mature, these deep sea creatures hold onto their eggs, Bush mentioned. 

It's not easy to come across such animal behaviors in the deep sea. The oceans are vast, and creatures aren't densely packed together, Bush told Mashable. "Animals in oceans are nowhere near as dense as what we're used to seeing, like from Discovery Channel or National Geographic programs."