Environment
Plastic doesn’t just look like food, it smells, feels and even sounds like food.
In an interview about Blue Planet II, David Attenborough describes a sequence in which an albatross arrives at its nest to feed its young.
“And what comes out of the mouth?” he says. “Not fish, and not squid – which is what they mostly eat. Plastic.”
The prevalence of plastic consumption is partly a consequence of this sheer quantity. In zooplankton, for example, it corresponds with the concentration of tiny plastic particles in the water because their feeding appendages are designed to handle particles of a certain size. “If the particle falls into this size range it must be food,” says Moira Galbraith, a plankton ecologist at the Institute of Ocean Sciences, Canada.
Like zooplankton, the tentacled, cylindrical creatures known as sea cucumbers don’t seem too fussy about what they eat as they crawl around the ocean beds, scooping sediment into their mouths to extract edible matter. However, one piece of analysis published by Science Direct suggested that these bottom-dwellers can consume up to 138 times as much plastic as would be expected, given its distribution in the sediment.
For sea cucumbers, plastic particles may simply be larger and easier to grab with their feeding tentacles than more conventional food items, but in other species there are indications that plastic consumption is more than just a passive process. Many animals appear to be choosing this diet. To understand why animals find plastic so appealing, we need to appreciate how they perceive the world.
“Animals have very different sensory, perceptive abilities to us. In some cases they’re better and in some cases they’re worse, but in all cases they’re different,” says Matthew Savoca at the NOAA Southwest Fisheries Science Center in Monterey, California.
“There’s this misconception that these animals are dumb and just eat plastic because it is around them, but that is not true,” says Savoca. The tragedy is that all these animals are highly accomplished hunters and foragers, possessing senses honed by millennia of evolution to target what is often a very narrow range of prey items. “Plastics have really only been around for a tiny fraction of that time,” says Schuyler. In that time, they have somehow found themselves into the category marked ‘food’.