International Cephalopod Awareness Days

Who among us knows that we celebrate International Cephalopod Awareness Days every year? What exactly are cephalopods, and why has it been deemed important to learn more about them? Long, long ago, before the ancestors of fish grew fins and the ancestors of birds grew feathers, the Earth was ruled by astonishing monsters. They survived 400 million long years, including several global extinctions, emerging after each one in greater numbers and more beautifully. They filled every available niche – from gentle herbivores to bloodthirsty hunters.

Some were smaller than a fingernail, while others became the largest creatures to ever inhabit the Blue Planet. They are still with us today – on store shelves, during oil exploration, or on vacation. Of course, we’re talking about cephalopods, Cephalopoda, because dinosaurs ruled for much less time. Yet far more people have heard of dinosaurs, while even professional zoologists have never heard of many cephalopods, even after they became popular in private aquariums, for example, Wunderpus photogenicus [5, 7].

International Cephalopod Awareness Days – where and when are they celebrated?

To change this, coastal nations celebrate International Cephalopod Awareness Days (World Cephalopod Week) annually from October 8-12. As part of this ecological celebration, numerous events are organized in schools, aquariums, and coastal resorts. The goal is to raise public awareness about the issues faced by this group of mollusks, while also having fun. The shared name for the events remains deliberately ambiguous. It refers both to the awareness of the broader public and to their animal stars [1, 2, 3, 5].

A few words about cephalopods

Cephalopods are a class of invertebrates belonging to the mollusk phylum, found in the fully saline seas of subtropical zones, in the goblet collections of Polish magnates, or in geological museums – in the form of fossils. They are united by having eight or ten arms surrounding a beak-like mouth made of chitin, a direct development process with internal fertilization and death right after reproduction, and a fully fused mantle that encloses the internal organs.

As mollusks, they are the opposite of their bivalve cousins due to their highly developed brains, advanced sensory organs, extraordinary mobility, and, typically, the lack of a shell. They are the true aristocrats of the animal world – they have blue blood, and their lineage dates back at least 570 million years [4, 5, 6, 7].

What are the themes of the International Cephalopod Awareness Days?

October 8 – World Octopus Day – honors all eight-armed cephalopods: 250-300 species of octopuses and one species of vampire squid, making up the order Octopodiformes. In this group, we find the greatest geniuses and most sensitive beings of the invertebrate world, master craftsmen who unscrew jars to reach a crab, notorious escape artists from aquariums, as well as excellent fortune-tellers, accurately predicting the outcomes of future matches. This group includes the paper nautilus, known from Mickiewicz’s “Ode to Youth,” frilled octopuses with arms linked along their entire length by a swimming membrane, and the vampire squid, a transitional link between octopuses and decapods [4, 6].

Nautilus Night – October 9 – promotes knowledge of the most archaic cephalopods. Nautiluses are the only ones that have retained impressive external shells. Thanks to numerous gas-filled chambers inside, the animal can regulate its depth in the water. Contrary to what is sometimes heard, the spiral of the shell is not truly a golden spiral created by the golden ratio of a circle. Nevertheless, the external skeleton is still sought after as an ornament or vessel, which is why their threat categories are rising under the Washington Convention.

The nautilus is a true living fossil, significantly deviating from the definition of a normal cephalopod. It has about 90 small, retractable tentacles that are not homologous to the arms of octopuses and decapods. It barely distinguishes light from darkness, as its eyes are primitive pits with a layer of light-sensitive cells, lacking lenses and vitreous bodies, unlike the sophisticated, vesicle-shaped eyes of other cephalopods, which can perceive not only colors and shapes but also the polarization of light [3, 5].

The next day – October 10, known as Squittleday (World Cuttlefish and Squid Day), familiarizes people with the issues of all decapods. This group includes species known from cans, as well as cuttlefish familiar to bird breeders. Among them, we find live jets – the fastest marine invertebrates in the world, outstanding painters squirting self-portraits from their own ink, and the giant squid – the largest invertebrate on the Blue Planet. They impress by changing their appearance literally at the speed of human thought.

The colossal progress in today’s physiology and medicine, awarded the Nobel Prize in 1963, was made possible by experiments on the giant axon of squids. Despite the name, it wasn’t isolated from the carcasses of the largest decapods, as all squids possess nerve cells hundreds of times larger than those of humans or cats [4, 6, 7].

October 11 – Kraken Day is a time for reflection on the portrayal of cephalopods in fine arts and popular culture. On this day, we recall the mythical sea monsters from the oldest human sagas, as well as their more recent depictions. Giant octopuses or squids appeared in the pages of Melville’s Moby Dick, Verne’s 20,000 Leagues Under the Sea, and Hugo’s Workers of the Sea. They inspired Lovecraft’s demonic Cthulhu from his horror stories. On Kraken Day, it’s worth remembering not only the discoverers of the real kraken, the giant squid, but also all cryptozoologists, who combine the enthusiasm of a seeker with a passion for verifiable, unembellished facts [1, 2, 3].

The last of the cephalopod days – October 12 – Ammonite and Belemnite Day reminds us of all the extinct representatives of Cephalopoda, far more numerous than the modern ones (nearly 17,000 species compared to 800 today). Although dead and fossilized for millions of years, they still have some influence on human life. As index fossils, they not only allow for dating rocks but can indicate oil and gas deposits, impacting the economy and provoking new wars.

Ammonite and Belemnite Day could catch on in Poland better than the other days of Cephalopod Week. Fossilized remains of these mollusks are abundant in the Devonian rocks of the Świętokrzyskie Mountains and the Sudetes, as well as in the Mesozoic formations of Roztocze, the Miechów Upland, the Kraków-Częstochowa Upland, and the Tatra Mountains. Polish paleontology has been playing in the global major league for decades, and among the discoverers of the last, Tertiary ammonites, there have been Poles [3, 5, 7].

In the article, I used the following sources:

1. https://naturalsciencesresearch.wordpress.com/2012/10/04/cephalopod-awareness-days-october-8-12th-arm-yourself/
2. https://oneworldoneocean.com/blog/cephalopod-awareness-days-october-8-12/
3. https://sanctuaries.noaa.gov/news/oct20/cephalopod-days.html
4. Anderson R., Mather J., Wood J. 2013. Octopus: The Ocean’s Intelligent Invertebrate. Timber Press, Oregon.
5. Samek A. 2020. Głowonogi. Mięczaki niezwykłe. Wyd. AGH, Kraków.
6. Smith-Godfrey P. 2019. Inne umysły. Ośmiornice i prapoczątki świadomości. Copernicus Center Press, Kraków.
7. Staaf D. 2022. Monarchowie mórz. Niezwykła opowieść o 500 milionach lat ewolucji głowonogów. Prószynski i S-ka, W-wa.