WOODS HOLE, Mass. — The cuttlefish, as small and testy as a hand grenade, was refusing to cooperate.
Close relatives of squids, flamboyant cuttlefish are camouflage experts that can dramatically alter their skin textures and colors. Biologists who study this feature at the Marine Biological Laboratory put cuttlefish into a circular tank filled with black and white pebbles. Most of the many-armed subjects hunker down, become black and white, and fade into the background.
Not this one. It swam laps, ignoring the pebbles, and curled two arms upward like tusks, which it turned cranberry-red. The cuttlefish squirted a little plume of ink. The supervising researcher sighed. So went another afternoon at the seaside science hub.
In a cavernous laboratory here, scientists are raising thousands of octopuses, cuttlefish and their kin as part of the Cephalopod Program, a three-year-old initiative to transform these sea creatures into the next lab animals. Cephalopods ooze scientific appeal: They have complex bodies, unusual genetics, impressive spatial skills and intelligent minds. Yet the animals can be reluctant to breed, hard to raise and difficult to keep from escaping their tanks. Few laboratory protocols — and, in the United States, no legal regulations — offer guidance.
Cephalopods “are considered the most alien form on the planet, the only invertebrate capable of higher order cognitive tasks,” said squid expert Erica A.G. Vidal, a marine scientist at the Federal University of Parana in Brazil and a former president of the research organization the Cephalopod International Advisory Council. She said the research community is small, with about 500 scientists worldwide, but she estimated the community increased by about 30 percent between 2012 and 2018.
In January, the Marine Biological Laboratory announced it was the first facility to
raise multiple generations of pygmy zebra octopuses.
“This is the first effort to go make a genetically tractable model,” meaning a species with catalogued and manipulable genes, said neurobiologist Joshua Rosenthal, who leads the laboratory’s initiative. He wears a surfer-dude grin while describing the intricacies of cephalopod genetics. As a rule, cells precisely turn DNA sequences into RNA and transform this RNA into proteins. But cephalopods use enzymes to edit genetic information in RNA, the only animals known to so frequently subvert this basic process of molecular biology.
Like a cook who changes a recipe to taste, cephalopod cells tweak this RNA. The animals most frequently rewrite RNA codes to make new proteins in their neurons. Rosenthal predicts RNA editing could be adapted for human therapeutic purposes, such as temporarily shutting off a cell’s ability to signal pain.
Cephalopods are “fantastically bizarre,” said Caroline Albertin, a developmental biologist at the Woods Hole facility. In 2009, Albertin was interviewing with neurobiologist Clifton Ragsdale for a graduate student position at the University of Chicago. Ragsdale gave her a tour of his laboratory. Inside a massive tank sat a single octopus egg. Inside that was an embryo. Within its transparent eggshell, the embryonic octopus began to transform, rippling with colors.
“And as we were watching, it hatched out, changed colors, inked and swam away,” Albertin said. She was hooked. Years later, Albertin and Ragsdale sequenced the first octopus genome — of the same species, the California two-spot octopus, the young biologist watched hatch.
Cephalopods are of Earth but apart from us. To find the last common ancestor of cephalopods and humans, we must travel back more than 800 million years. Some kind of tiny worm, probably, wriggles at the roots of this family tree. As the tree splits, fruit flies, leeches and squid arise on one side. On the other are mice, Tyrannosauruses and great apes.
Neuroscientists probe cephalopod brains to examine what arose on their side of this evolutionary chasm. Five hundred million neurons, about as many as in a rabbit, make up the nervous system in the common octopus.
The majority of these neurons are packed into the octopus’s eight arms, not its brains, suggesting a decentralized intelligence in which arms are involved in making decisions. A severed octopus arm pulls away from acid. (A disembodied human limb does not.)
“If we can make contact with cephalopods as sentient beings, it is not because of a shared history, not because of kinship, but because evolution built minds twice over,” wrote philosopher and scuba diver Peter Godfrey-Smith, in his 2016 book “Other Minds.”
“They have these amazing behaviors,” Albertin said. “They’ve got these beautiful, weird body plans.” Three hearts, pumping bluish blood, beat within an octopus. A doughnut-shaped brain encircles its esophagus.
Some cephalopods can break free from their tanks, such as an octopus named Inky that crawled out of a New Zealand aquarium in 2016 and followed a drainpipe to the Pacific Ocean. In 2009, biologists reported that wild octopuses near Indonesia carry discarded coconut shells, which the animals use as transportable shelters. This, depending on the animal behavior expert you ask, counts as tool use.
“They know when you’re not looking at them anymore,” said Bret Grasse, who manages the cephalopods at the Marine Biological Laboratory. Something once splashed Grasse when, near a tank of cuttlefish, he turned to talk to a colleague. He whirled around to catch the culprit. Nothing was out of place; the animals floated near the bottom of their tank. He resumed the conversation and was splashed again. Grasse set his phone to take mirror-mode video and, on the screen, watched the animals over his shoulder. Several cuttlefish rose to the top of the water and began squirting at the back of his head. “And as soon as you turn around they go right down to the bottom.”
For most of its history, cephalopod research, like seafood specials, relied on the catch of the day.
Although humans have kept cephalopods in tanks since the 1800s, breeding and raising them is difficult. That’s particularly true for octopuses, said George Parsons, a curator at Chicago’s Shedd Aquarium and an expert in invertebrate husbandry. “If you don’t do it just at the right moment, then that territorial instinct overtakes the reproductive instinct,” Parsons said.
The Seattle Aquarium tried to get its giant Pacific octopuses to mate in an annual Valentine’s Day spectacle. (A male octopus delivers sperm, in what Parsons called “a really pretty three-foot-long capsule,” by sticking his arm through the female’s gills. She stores the capsule inside her body until she smashes it open over her eggs.) The aquarium canceled these unsuccessful dates in 2016, concerned that the octopuses would try to eat each other.
In early breeding attempts, newborn cephalopods rarely survived to adulthood. David Remsen, who oversees the care of aquatic species at the laboratory, recalled a period of trial and error 20 years ago. Biologist Roger Hanlon, a camouflage expert, was trying to rear young Hawaiian bobtail squid. The animals, which grow to barely over an inch long, are even teensier when born. The researchers offered very small prey to the very small squid. The squid refused to eat.
“They were starving to death,” Remsen said. “Couldn’t feed them anything.” Out of frustration, the researchers served up large shrimplike crustaceans, three times the size of a hatchling. The hungry squid jumped at the crustaceans “like friggin’ lions on the top of wildebeest,” he said. There was a lesson in the carnage: “We just thought we knew what they wanted.”
Cephalopods are not only picky eaters but also acutely sensitive to water conditions. They have thin skin — in some cases, a layer of skin a single-cell thick separates the animal’s internal body chemistry from its external environment, Grasse said.
A crocheted squid sits on Grasse’s desk. It is neatly flayed to reveal yarn organs. This was a departing gift from a former co-worker at the Monterey Bay Aquarium, where Grasse developed the “Tentacles” exhibit, which he called “the world’s first large-scale cephalopod public display.” He spent four years in California trying to get the animals to breed, and designed a system, out of soda bottles, to keep their eggs suspended in water.
Caring for several thousand cephalopods at the Marine Biological Laboratory requires three full-time staff members plus five interns. In September, the National Science Foundation awarded Rosenthal $300,000 to cultivate a single species, the Hawaiian bobtail squid, as a genetic model. Additional funding comes from philanthropists, such as Prince Albert II of Monaco, who visited Woods Hole in July and fed an octopus. The lab raised about $1 million from the private sector to run the program for three years, Rosenthal said.
To manage this huge menagerie, the Cephalopod Program must raise small species, such as the marble-size pygmy zebra octopus. Even tiny octopuses are separated, to avoid cannibalism, and are allowed to mate only when well-fed. Other little ones include the striped pyjama squid and stumpy-spined cuttlefish; these species tolerate living in groups.
California two-spot octopuses are normally solitary, but when they are dosed with psychoactive drug commonly called ecstasy, they appear to be more social. That’s what Johns Hopkins University neuroscientist Gul Dolen and Eric Edsinger, a cephalopod scientist at the Marine Biological Laboratory, described in 2018 after they bathed five octopuses’ gills in liquid MDMA. The animals, which typically avoid other octopuses, seemed to relax while drugged. They swam much closer to tank-mates, and even began to touch. This result, the authors concluded, suggests that octopuses have molecules in their brain cells similar to our serotonin receptors.
Less than an hour after the journal Current Biology published Dolen and Edsinger’s pilot study, the activist organization People for the Ethical Treatment of Animals condemned the research and its authors.
“These experiments are indefensible, curiosity-driven nonsense . . . . The best way to understand and treat human disorders is to study humans, but that would be inconvenient,” wrote PETA’s science adviser, Julia Baines, in an unsolicited email to The Washington Post.
An ethics committee did not formally review or approve the procedures at the Marine Biological Laboratory, the authors wrote in their paper. Both the laboratory and Johns Hopkins “generally followed tenets prescribed by the Animal Welfare Act,” the authors wrote, including the “three Rs” of animal research: replacing animals with non-animal methods, reducing the number of test subjects and refining lab conditions to minimize stress.
In 2010, the European Union gave cephalopods the same protections as vertebrate lab animals. Canada has similar rules. The United States does not.
Neither the Animal Welfare Act nor the National Research Council’s guide to lab animals covers invertebrates. At the Johns Hopkins School of Medicine, cephalopods are treated under protocols developed for mice. Its animal ethics committee is developing specific rules for cephalopods, Dolen said.
“I’ve heard, on the ground, that some people are also drawn to using them specifically because there is no regulation,” said Joanna Makowska, a scientific adviser to the Animal Welfare Institute, a Washington, D.C.-based organization that advocates for the three Rs. She was concerned that “no validated protocols” exist for cephalopod surgery, anesthesia or euthanasia. “We just don’t know enough about them.”
A 2018 study suggests that a magnesium chloride bath may be a good way to anesthetize an octopus. The Marine Biological Laboratory has developed protocols for cephalopod anesthesia, Rosenthal said. “But it’s an open question, and a difficult one. We don’t know how they sense nociception.” (The word “nociception” means painful feelings).
Becca Franks, who studies aquatic animal welfare at New York University and recently published a paper that opposes the domestication of octopuses for food, pointed out that fish have surpassed mice as the most popular vertebrate animal in the lab. “There’s this almost schizophrenic approach that applies both to fish and octopus,” Franks said. “Of being fascinated by them because they are so much like us. And then, sometimes, using that as justification for specifically doing things to them that wouldn’t be acceptable to do to humans.”
“Octopuses are so remarkable that it would be good to learn more about them,” said the philosopher Godfrey-Smith, one of Franks’ co-authors on the octopus farming paper. “A lot of embryological and developmental work can be done in a way that is not especially inhumane. And, of course, it is possible also to do behavioral experiments that do not involve surgery or other invasive procedures at all.” Hanlon’s camouflage studies at the Marine Biological Laboratory, which use the black-and-white pebble tank, require nothing more intrusive than a video camera.
Godfrey-Smith was afraid of the possibility for “cruel” experiments, however. “It is hard to do neuroscience on complex organisms without harming them.”
He added: “If there were compelling reasons why work on cephalopods would yield results that would help us with specific medical problems, that would also change the situation. But I’ve not seen claims of that sort so far.”
Rosenthal predicts that the United States will follow Europe’s lead in extending protections to cephalopods.
“Look, no one likes all the paperwork, and stuff like that,” he said. “But if you are trying to justify it biologically, I think that they probably should be.”
A handful of animals — small and quick to breed, such as mice or flies — dominated laboratory science for most of its existence. That is changing. The biologist’s toolbox encompasses more unusual species.
Marine Biological Laboratory scientists, for instance, are raising frilled salamanders that don’t scar, lampreys that regenerate their spines and microscopic animals, called rotifers, that steal genes from plants. Rosenthal and his colleagues seem confident that cephalopods, despite their bizarre lifestyles and escapee tendencies, will occupy their own toolbox shelf.
Some of those cephalopods will probably be mutants.
In 2018, Marine Biological Laboratory researchers managed to insert the gene-editing system CRISPR into squid embryos. The scientists targeted pigment genes to erase skin and eye colors. There is more work to do. Splotches of pigment, signs of an imperfect success, remained.
Rosenthal does not predict a massive surge in scholarship totally devoted to squid. Instead, the curious geneticist or neurologist of the future may take a sojourner’s approach to cephalopods. Rosenthal imagines a scientist traveling, from the world over, to what he called a cephalopod “supercenter.” There, local experts would run an experiment with the visitor’s help. Then the pilgrim researcher returns home with fresh data, made possible only by the most alien forms on Earth.