Aliens at our Doorstep

 

Nonfiction - by Peter Jekel 



 

Any entity—no matter how many tentacles it has—has a soul. 

                Guy Consolmagno


In 2015, University of Chicago neurobiologist Clifton Ragsdale, co-leader of the team that performed the genetic sequencing of the California two-spot octopus, jested in the journal Nature, “It’s the first sequenced genome from something like an alien.” The press took the quote and ran with it. For a brief time, octopuses were seen not as creatures of Earth but as aliens from beyond, although when we re-listen, “like an alien” is a lot different from “being an alien.”


The media’s misconception is understandable. The wide range of depictions of aliens in fiction, film and tabloids includes bug-eyed monsters, little green men, giant insects, facially altered humanoids—and tentacled beings that look a lot like octopuses and the other cephalopods: squid, cuttlefish, and the more primitive nautilids. All have “alien” characteristics that make them attractive to the creators of myth, legend and speculative fiction. First and foremost of those characteristics is intelligence.


Cephalopods are molluscs, the second largest class of invertebrates after arthropods, but they’re nothing like their shelled relatives, the clams, mussels, scallops, oysters, and snails (or slugs, a shell-less snail), because cephalopods, especially octopuses, are smart.


Have you ever seen how octopuses can figure out how to get to prey encased in a jar, or their ability to escape a fishing vessel after being hauled aboard? Sometimes they even climb aboard fishing vessels to make an easy meal of trapped lobsters and crabs. They have the largest brain-to-body-mass ratio of any invertebrate, falling, in comparison to vertebrates, between cold-blooded (reptiles, fish, amphibians) and warm-blooded (birds and mammals) animals.


Octopuses have been trained in laboratories to distinguish shapes and patterns. One study suggests they can learn by observation, which had been thought to happen only in birds and mammals. Another study indicates octopuses learn from one another, also normally expected only among birds and mammals. In the experiment, common octopuses who watched other octopuses select between two objects of different colours then selected the same object themselves.


Tool use is another sign of intelligence. Octopuses have been found to use empty coconut shells as shelter. Crabs and other species also use discarded coconut shells as shelter, but octopuses will move a shell for later use, indicating that they plan for the future.


Tool making is another octopus talent. Their highly sensitive tentacles act almost like primate hands, allowing them to manipulate objects. They have been found to build walls around themselves with stones, shells, and in one experiment, Lego bricks.


Captive octopuses, like domesticated cats and dogs, become bored without stimulation. At an aquarium in Coburg, Germany, an unhappy octopus named Otto threw rocks at his glass enclosure, tossed his tankmates around, and even short-circuited an overhead lamp with a jet of water from his siphon.


Humboldt squid demonstrate cooperation, also a sign of intelligence, by utilizing teamwork and communication in hunting, not unlike lions, wolves, orcas and other vertebrate predators.


The way cephalopods communicate can definitely be described as “alien.” In addition to changes in posture and locomotion, they communicate with colour and texture alterations in their skin. Such changes initially evolved as camouflage from predators and prey but have become more complicated. Some squid species flash patterns and colour during courtship. Some apparently use colour variations in a manner similar to grammar.


The complex skin communications are accomplished by nerve control of cells called chromatophores. Chromatophores are pigment-containing or light-reflecting cells found in a range of crustaceans, fish, amphibians, reptiles and, of course, cephalopods. Mammals and birds have lost their chromatophores, relying instead on cells known as melanocytes to give them colour. In cephalopods, however, chromatophores do much more than control colour.


In organisms other than cephalopods, colour changes occur through the movement of pigments within the cell. Cephalopod chromatophores are complex and multicellular and are supported by muscles, nerves and glial cells. Inside the chromatophores are granules of pigment enclosed in an elastic sac. The organism changes colour by contracting muscles to distort the sac.


The eyes of cephalopods are large, and similar to those of sharks, enclosed in a cartilaginous capsule attached to the cartilaginous cranium. Unlike sharks, however, cephalopods have everted retinas and  lack corneas (the transparent covering of the eye that, together with the lens, is responsible for approximately two-thirds of the eye’s visual power). The position of the retina differs from that of a vertebrate eye; the distal end of the photoreceptor cells lies directly behind the lens and connects to the optic nerve behind the retina. This system is more efficient than that in vertebrates, in which the retina lies directly behind the lens and requires light to pass through the neural apparatus and retinal capillaries before reaching photoreceptor cells. As a result, vertebrate eyes have a blind spot not found in cephalopod eyes. 


Ironically, for all their visual acuity and colour-changing ability, cephalopods are essentially colour-blind; however, new research has found some species that use chromatophores in their skin to “sense” colour in their environment. Even more amazing, cephalopods are able to change colour and pattern in milliseconds, not seconds or even minutes as in other colour-changing animals.


Intelligence and communication are a couple of aspects that make cephalopods almost “alien,” but other body systems are no less amazing.


Cephalopods are the only molluscs with tentacles. The “foot” of all molluscs is a muscular appendage that allows for locomotion. In cephalopods the “foot” has evolved into eight or ten flexible and manipulative tentacles attached to one another at the base by a webbed structure surrounding the mouth. The tentacles consist of a thick central nerve cord surrounded by muscle and can extend, contract, twist, bend and even become rigid. Octopuses in particular explore their environment with their tentacles and can even taste with the suction cups that line them.


Octopuses’ bodies are made up of tissue that can be manipulated a lot like Play-Doh™, allowing even the largest to squeeze through openings as small as two-and-a-half centimeters in diameter.


Squid, nautilids and cuttlefish move through a wave-like action of their fins. Octopuses, however, have been observed “walking” on their tentacles across the ocean floor, in some cases bipedally despite having eight arms.

Cephalopods can also move using a system of water-powered jet propulsion: they draw water into the body, or mantle, and expel it through a siphon at the anterior of the mantle. The siphon has chemoreceptors that allow the animal to taste the water. Jet propulsion is one of the most efficient ways of moving (even more efficient than a rocket). Although it becomes less efficient as the size of the animal increases, it still allows for incredible acceleration to evade predators and capture prey.


Cephalopods, with the exception of the primitive nautilids and a few species of octopuses, protect themselves with a unique weapon, a cloud of dark ink expelled from a sac that lies beneath the gut and opens into the anus. The ink is almost pure melanin mixed with mucus. It impairs the vision of a pursuer much like a smokescreen.


Among molluscs, only cephalopods have a closed circulatory system similar to that of vertebrates. In a closed system, blood is circulated throughout the body, pumped by a heart to capillaries that surround the organs. In an open system, there is no true heart, and blood (known as hemolymph) is forced through the body by contraction of blood vessels into open sinuses in which the organs are bathed with oxygen and food and waste products are removed.


Although cephalopod circulatory systems are similar to those of vertebrates, there are several important differences. The higher cephalopods (octopuses, squid and cuttlefish) have three hearts: two gill hearts that pump blood through the blood vessels of the gills and a systemic heart that pumps oxygenated blood through the rest of the body. Nautilids have only one heart.


The blood of cephalopods, like all molluscs, is different from that of vertebrates and more like that of the Vulcans of Star Trek. Mollusc blood uses a copper-based protein called hemocyanin rather than iron-based hemoglobin. Whereas Mr. Spock’s blood has a green hue, that of the cephalopods turns blue when exposed to air.


All cephalopods “breathe” or exchange gases by forcing water through their gills. Unlike other ocean dwellers, however, the gills of cephalopods also seem to be involved in excretion.


Cephalopods feed through a two-part beak made of chitin (the same material as the exoskeleton of insects). They capture prey with their tentacles and pull it to their mouths. They digest using a mixture of toxic juices, some of which are manufactured by symbiotic algae.


Although cephalopod anatomy is bizarre, cephalopod genetics are unique. Genetic sequencing has been challenging because their DNA is exceptionally long and repetitious. It is hypothesized that the repetition is the result of genome duplications. 


A genome duplication is any duplication of a region of DNA that contains a gene. Duplications often arise out of errors in DNA replication and repair machinery. With respect to the sequencing of the California two-spot octopus, no evidence of full genome duplication has been found and in fact their genomes have many similarities to those of other marine species.


There are, however, a number of differences. The California two-spot’s genome isn’t made up entirely of genome duplications, but there are substantial duplications within two gene families. One family is the protocadherins associated with neuron development and essential for the development of synapses, the connections between nerve cells. The other is known as C2H2 and is involved in zinc transcription factors essential to the moderation of DNA, RNA, and protein functions within the cell. At around 1,800 genes, the California two-spot’s C2H2 family is one of the largest gene families in the animal kingdom, second only to the  2,000 genes involved in an elephant’s olfactory receptors.


The California two-spot’s genome also shows a significant number of transposable elements. A transposable element is a DNA sequence that can change its position within a genome, an essential trait in the creation and reversal of mutations that alter a cell’s genetic identity and genome size. The significance of this trait in octopuses is not well understood, but the transposable elements are predominately in the sequences involved in neuron development and diversity. In mammals, neuron diversity seems to be linked to increased memory and learning, so this finding is in keeping with the octopus’ larger brain and its strange anatomy.


The octopus genome also contains specific genes found only in octopuses, expressed in their unique tissues. Their suckers, for example, are the result of a curious set of genes similar to those that encode receptors for the neurotransmitter acetylcholine. Six other genes encode for proteins called reflectins and are expressed in the skin; they work by altering the way the skin reflects light rather than by expressing a colour of their own.


Such unique genes are known as ORFans: they are “orphan” genes without an apparent evolutionary origin.  Although unusual, they are found in other animals, including the ORFans that produce the antifreeze protein found in a species of Antarctic fish. Even humans have a few ORFan genes, three of which have emerged since the divergence of humans from chimpanzees.


A unique phenomenon of all cephalopods is that they are more able than any other organism to edit their own RNA. Their capability is around sixty percent compared to less than one percent for humans and fruit flies. In cephalopods, RNA editing is concentrated in the nervous system and affects the proteins involved in nerve function and neurology. As a result, structures and editing sites are conserved in the cephalopod genome while mutation rates are severely hampered, at a cost of slower evolution.


Evolution works by changing DNA in a way beneficial to the host. Normally RNA’s role is to transmit genetic code to create proteins. By being able to edit their RNA, cephalopods can essentially rebuild themselves. However, doing their own RNA editing comes at the expense of the evolutionary potential of DNA. In fact, it has been found that octopuses and their cousins not only have forgone the benefits of DNA evolution but regularly edit their RNA. In the common squid, up to sixty percent of the RNA in their nervous system has been edited to their advantage, allowing their brains to adapt to changing ocean temperatures.


Although there are similarities between the cephalopod genome and those of other animals, the similarities are not those predicted by common descent. Rather they can be attributed to convergent evolution.


Even within the cephalopod group itself, there is evidence of convergent evolution and not common descent. The protocadherin genes arose independently in squid and octopuses; octopus protocadherins expanded 135 million years after the species diverged from squid.


How have cephalopods inspired storytellers? Let’s take a look.


In Hawaiian creation myth the current universe is the last of a series that arose from the ruins of the previous universe; the octopus is the lone survivor of the previous era, making it an alien from an earlier time and place.


The kraken are legendary sea monsters that, according to the Norse sagas, lurk in the seas around Scandinavia and all the way across the North Atlantic to Greenland. An anonymous Greenlandic author stated in 1250 that there must be only two krakens in the world, due to their enormous size. Although kraken are just legend, Swedish biologist Carl Linnaeus, who formalized the binomial nomenclature for all living things, depicted the creatures as real in his ground-breaking 1735 Systema Naturae. He dubbed them Microcosmus marinus. Many researchers have hypothesized that the kraken legend has its origin in the giant squid, which can grow up to fifteen meters in length. In fact, the elusive giant was never filmed in its ocean habitat until 2012.


Many fiction writers have depicted cephalopods, especially the giant squid and the mythic kraken, as monsters. In Moby Dick, Herman Melville devotes a whole chapter to the giant squid. Starbuck calls it, “The great live squid, which, they say, few whale-ships ever beheld, and returned to their ports to tell of it.”


In H. G. Wells’ 1896 short story, “The Sea Raiders,” a pack of giant squid attack people in boats as well as on shore. 


Another early science fiction writer, Jules Verne, probably created the most famous kraken villain of all time, the antagonist of his 20,000 Leagues Under the Sea.


Master horror writer H. P. Lovecraft created an octopus-like monster, Cthulhu, in his 1928 short story “The Call of Cthulhu” and featured it in a number of his tales. It sleeps at the bottom of the ocean to be awakened in a coming apocalypse. It is often depicted as a creature with the head of an octopus and multiple tentacles. Lovecraft scholars have stated Cthulhu’s origin was Alfred Tennyson’s poem “The Kraken.”


Taking a page from Lovecraft, J. R. R. Tolkien’s Lord of the Rings features the Watcher in the Water, loosely described and represented in the movie franchise as a squid-like giant that guards the gates of Moria, the labyrinth of tunnels, rooms and mines under the Misty Mountains.


Beast, by Peter Benchley, is about a giant squid terrorizing Bermuda. He added one extra piece to his beast—not only does it have a deadly beak, but each sucker on its tentacles has claw-like teeth at the centre.


In James Rollins’ The Judas Strain,  schools of octopus squid, one of the largest squid species, make predatory attacks featuring pack-like cooperation.


Michael Crichton used giant squid as antagonists in his Pirate Latitudes. The creature that terrorizes the hero’s ship is known as the kraken. In his Sphere, an undersea habitat is attacked by a number of smaller squid and later by a giant squid.


James Bond, superspy, fights giant squid in Ian Fleming’s Dr. No. Fans of the movie franchise will note that the scene is missing from the movie.


Roland Smith wrote a series of young-adult science fiction novels about cryptids. In the second book, Tentacles, the main character is hired to capture a giant squid for a zoo. The giant squid are portrayed as pack hunters instead of the solitary hunters scientists know them to be.


Arthur C. Clarke’s The Deep Range also features the capture of a giant squid. In his short story “Big Game Hunt,” Clark writes about using a device capable of controlling the behavior of invertebrates to capture and film a giant squid.


Squid are not always portrayed as villains. China Mieville’s Kraken follows a cult that worships squids. In J. K. Rowling’s Harry Potter series, a giant squid that lives in the lake at Hogwarts is friendly and acts as a lifeguard if a student falls into the lake. Artemis Fowl: The Time Paradox by Eoin Colfer describes the kraken as up to a third of a mile in length,  placid, and feeding  on algae.


Sometimes squid are portrayed as extraterrestrials. John Wyndham’s The Kraken Wakes is about an invasion of Earth by squid-like aliens. Jack Vance’s The Blue World, an expanded version of an earlier tale called The Kragen, is about a planet where the natives are wary of the kragen, a giant semi-intelligent squid-like predator.


Perhaps the best tale along this line was written by Michael Bishop. His Death and Designation Among the Asadi is about a scientist who becomes frustrated when he realizes the Asadi culture he’s studying is too complex for human science to understand.


Taking an Earth-centric tack, Ken MacLeod wrote an entire trilogy, Engines of Lights, in which giant squid are one of five intelligent species from Earth that colonized the Galaxy; the others are the dinosaurs and three species of hominids. In Stephen Baxter’s Time, squids have been genetically engineered to pilot spaceships.


Octopuses appear less frequently than squid in fiction and tend to be villains. Victor Hugo’s Toilers of the Sea features a battle with an  octopus. Octopussy and The Living Daylights are a couple of James Bond short stories featuring octopus battles.


One exceptional story featuring intelligent alien octopuses is Ted Chiang’s The Story of Your Life,  which was made into an equally exceptional movie, all too rare in science-fiction cinema. The 2016 movie adaptation, Arrival, features benevolent aliens known as heptapods that have seven limbs and a round head much like octopuses (there is a species of octopus that actually has only seven limbs instead of eight, Haliphron atlanticus). The complicated plot involves the development of communication with this very alien species. Their language and concept of time is nonlinear and totally different from those of humans.


The media cannot be faulted for extrapolating from Clifton Ragsdale’s statement that octopuses (and by extension other cephalopods) are “like aliens.” No other intelligence on Earth is as distantly related to us. Their anatomy, communication and physiology are nothing short of bizarre. Their genetics are unique. They demonstrate that intelligence has evolved at least twice on Earth, once in invertebrates and once in vertebrates, and that there is more than one route for achieving it (RNA editing versus DNA mutation). 


So if you happen to bump into any tentacled aliens when you’re out in space, don’t forget—they could be very, very smart. Be careful!

 

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