By Tina Beigi
Original Published in: Wastiary – A Bestiary of Waste. 2023. UCL Press.
The octopus is a scavenger: making good use of its eight tentacles, the cephalopod collects piles of broken scallop shells and converts them into shelters. Lately, favourite hiding spots have also included ceramic pots, metal pipes, rusted cans and beer bottles. This devious escape artist endowed with a large, complex nervous system is an incredibly intelligent problem-solver. In regions where human tourists collect an excessive number of seashells, the octopuses find alternatives in copious human garbage.
Upon close examination, the octopus’s garden is a seabed junkyard. In ‘Octopolis’, a den of ‘gloomy octopuses’ (Octopus tetricus) off the coast of Jervis Bay in Australia, divers found a 12-inch-long piece of garbage from a boat, which had been neatly arranged to fit the seascape.1 Assembling around the inescapable presence of human trash in the marine environment, octopuses have increasingly chosen manufactured remains instead of seashells or coral as dwellings. A newly discovered species, the pygmy octopus in Brazil (Paroctopus cthulhu), has only ever been observed sheltering in litter.2 Even deep-sea octopuses in the Mediterranean are making use of sinking rubbish, which raises the question: is the octopus a natural-born circular economist, turning waste streams into wealth?
Camouflage and ink squirting are among the behaviours that allow octopuses to survive in the ocean. Owing to their soft body, these molluscs are unprotected when hunting their prey; a shell can therefore provide more safety and increase their chances of survival. However, these mineral shells are cumbersome to lug around. By contrast, plastic cups are lightweight and durable and have become the octopus’s favourite exoskeleton.
Every so often, on the deep-sea highway, an upside-down plastic cup from which eight limbs creep out wanders past the shell-lives. Octopus fondness for plastic scaffolding may result from the added visual value that transparent plastic cups offer in addition to weight- lessness. And yet, to the scientists’ surprise, broken glass bottles are also used by octopuses as headcover, despite their heaviness: bottles once used as pharmaceutical product packaging find their way into the octopus’s wardrobe. But such ‘full metal jackets’do not come free of peril. Cadmium is a toxic chemical found in plastics, glass, batteries and many other common ocean pollutants. After exposure to cadmium, octopuses panic and synthesise a heat shock protein called Hsp70, which protects cells from the damaging effect of metabolic stress.3
Perhaps not unrelated to their metabolic stress, back in Octopolis, researchers also witnessed ‘trash’ behaviour: males and females alike exhibit vicious acts of aggression and eject one another from their synthetic dens.4 Far from the garden of Eden, Octopolis represents the lapsarian fall on the seafloor.
Despite the risks attached to hazardous trash, the octopuses find many usages for such items. Instead of bottling up their emotions, female octopuses apply trash-throwing skills, usually during den building or housekeeping, against males when feeling harassed! If the male survives this spring-cleaning ritual, he may not survive the lovemaking. The female typically kills and eats her own means of reproduction once the male has fulfilled his function. She playfully hugs the male with three arms and strangles him to death before gobbling him up into the recycling bin of her belly, where he will nourish the babies in the making. The octopus never wastes: it scavenges and repurposes human debris and sexual partners alike. This circular economy keeps turning: after laying a clutch of eggs, the mother stops eating, and by the time the eggs hatch, she dies.5 Octopuses are serious cannibals, and a biologically programmed ignominious end is perhaps their way to keep mothers from eating their young. Lab reports have even shown that captive females deliberately accelerate the death spiral, banging into the edges of the tank, pulling off chunks of skin, or chewing the tips of their own tentacles.6 As a semelparous species, the octopus reproduces once before dying. By self-mutilating, the octopuses repurpose their abandoned bodies and provide food abundance to the newborn.
So, yes: the octopus is a natural-born circular economist, turning waste – marine and land-based alike – into wealth. Notes
1 Peter Godfrey-Smith, David Scheel, Stephanie Chancellor, Stefan Linquist & Matthew Lawrence, ‘In the line of fire: Debris throwing by wild octopuses’, PLoS ONE 17:11(2022), article e0276482<https://doi.org/10.1371/journal.pone.0276482> [accessed 29 December 2022]. 2 Tatiana S. Leite, Erica A. G. Vidal, Françoise D. Lima, Sergio M. Q. Lima, Ricardo M. Dias, Giulia A. Giuberti, Davi de Vasoncellos et al., ‘A new species of pygmy Paroctopus Naef, 1923 (Cephalopoda: Octopodidae): the smallest southwestern Atlantic octopod, found in sea debris’, Marine Biodiversity 51, article 68 (2021) <https://doi.org/10.1007/s12526-021- 01201-z> [accessed 3 January 2023]. 3 Ling-Li Long, Ying-Li Han, Zhang Sheng, Chen Du, You-Fa Wang & Jun-QuanZhu, ‘Expression analysis of HSP70 in the testis of Octopus tankahkeei under thermal stress’, Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 187 (2015), pp. 150–9, <https://doi.org/10.1016/j.cbpa.2015.05.022> [accessed 3 January 2023]. 4 David Scheel, Stephanie Chancellor, Martin Hing, Matthew Lawrence, Stefan Linquist & Peter Godfrey-Smith, ‘A second site occupied by Octopus tetricus at high densities, with notes on their ecology and behavior’, Marine and Freshwater Behaviour and Physiology 50:4(2017), pp. 285–91.
5 Z. Yan Wang & Clifton W. Ragsdale, ‘Multiple optic gland signaling pathways implicated in octopus maternal behaviors and death’, Journal of Experimental Biology 221:19 (2018),jeb185751 <https://doi.org/10.1242/jeb.185751> [accessed 27 October 2022].
6 Z. Yan Wang, Melissa R. Pergande, Clifton W. Ragsdale& Stephanie M. Cologna, ‘Steroid hormones of the octopus self-destruct system’, Current Biology 32:11(2022), pp. 2572–9.e4,
<https://doi.org/10.1016/j.cub.2022.04