This week I have a job to do. I’m charged with reviewing threatened species in the East Melanesian Islands to identify which animals are possibly threatened by hunting. The islands have many endemic rats and mice. The Solomon Islands have the Emperor Rat, King Rat and Poncelet’s Giant Rat. Nearby in Australia, the continent is characterised as much by rodents, as it is by kangaroos. There are more than 60 species. Rodents have always been part of our lives. Indeed, many of the most important and prolific animals that today we call ‘pests’ shaped our existence and continue to do so. What lessons can we learn from rodents? Have we underestimated their importance? Should we be more thankful for all the rats?
Rodents: harbingers of disease or cleaners?
IA recent study shows an increase in the number of rats living in Sydney. Even though these scientists refer to them as ‘vermin’ and ‘pests’ they can’t honestly justify their own rhetoric.
The fact we associate rats with disease and danger is only one small part of the story and may not even be that significant. For instance, the common misconception that rats caused the Black Death has been put to rest. It’s now thought that human fleas and lice were blame. Humans, in other words, were the problem.
What about the residual risk of catching leptospirosis or rat lung worm disease?
The latter is caught by consuming slugs and snails. Washing your garden vegetables thoroughly is the antidote (or not eating snails). As for leptospirosis, that’s a more serious problem. But that risk comes from directing our waste stormwater into the very places we bathe and swim: our rivers and beaches. The same factors that are killing and polluting our coastlines are contributing to disease – once again, it’s our behaviour, not the rats that are to blame. We are, to quoin a phrase, at risk of ‘throwing the rats out with the bathing water!’
Imagine how much dirtier and toxic it would have been to live in London in the 1300s if rats had not been there to clean up the capital’s waste.
Polynesian Rats as food
The Polynesian rat is an abundant species in the Pacific. It’s thought to have been introduced deliberately to many islands, brought by early settlers as food. Recent archeological work on Easter Island suggests the majority of the human population fed on rats as a key food source. Rodents breed fast. Indeed, this is also perhaps one of the traits that made them so valuable to early Pacific seafarers as food. Thus rats became immortalised in Pacific creation mythologies as gods and kings.
If you’re planning to settle on a remote island, fishing isn’t the easiest way to make a living. Fishing is tough. Water is cold and it takes extraordinary energy to lift fish from the sea. Humans, being land-dwellers, usually look away from the sea to find sustenance. That said, fish have become a major protein source, possibly due to the degradation of land ecosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More and development of technology combined. However, even those systems are being depleted now, leaving one wondering what happens next. Rats appear to have been crucial for the settlement of new indigenous people across the Pacific. How might we rely on them in future?
Nature’s changing food tapestry
First nations scholar Tyson Yungkaporta believes our future is with eating rats and mice. He proposes that humans might change in size and physical appearance, enabling us to hunt rodents as we gradually eliminate the larger fauna species from our world.
Last time we had this kind of climate change (drying and warming) our megafaunaThe largest animals that represent the top of the trophic pyramid. These are the final building blocks in ecosystem structures for maximum entropy production. Megafauna can be measured at any spatial scale. The largest animal that ever lived on Earth is the Blue Whale. In a grassland, spiders could be considered megafauna The term is generally reserved for animals larger More scaled down to human/roo size. This time we think smaller, like rat/cat size, and that’s what we’ll be hunting for meat if we can’t afford a $500 beefsteak. Over two centuries we humans would shrink as well (Tyson Yunkaporta, LinkedIn in October 2023) – excerpt from How to Survive the Next 100 Years
In Wildlife in the Balance I identified three mechanisms that enabled human society to reach its current point: transfer(of nutrients) the thing that sets animals apart from plants, is that they can move. Some of the biggest migrations on Earth every day, are the movement of insects like caterpillars, from the stem of a plant to a leaf and back, before turning into butterflies and transferring the energy elsewhere. Large-scale migration of grazing animals and migratory songbirds moves More, concentration and amplificationAmplification (of nutrients and energy). Animals consume plants and other animals and in doing so, reintroduce important energy-containing nutrients back into the environment, at even higher concentrations and in patches. Amplification of energy is driven by migration and happens at every scale, from insects moving daily in and out of your vegetable patch, to African wildebeest herds and the seasonal More of nutrientsEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More. Because humans live in the centre of the food chainA single thread in a food web illustrating the chain of animals that eat each other. At the base of the food chain are small high-energy (fast metabolism) animals and at the other end large low metabolism animals. An example would be whales eating krill that eat plankton that eat algae. Or lions that eat gazelles that eat grass. More, we rely on animals both above and below us. The larger animals created high concentration energy patches sufficient to support a large-bodied mammal like us for thousands of years. These became the richest farming areas in the world. The nutrients we built our cities on, were deposited over millions of years by tribes of animals walking across the Earth.
The smaller animals, meanwhile, cleaned up the waste that these larger animals produced and this counteracted nature’s forceful dissipation of energy (without wildlife driven energy structures the capacity for all animal survival ceases). The living systems we have today are because animals enabled energy to be contained in a living system: a steady stable system. A fair climate of living. For humans, this combination meant a clean and predictable living area, and ample, sustainable food production, all of it delivered by nature’s hand. No amount of AI thought or other technology will change this fact.
Lessons from rats and mice
As we enter a new phase of humanity where we no longer have access to high-energy food patches, we become increasingly dependent on the smallest animals to rebuild soil organic layers, microbial processes, water cycles and ultimately, climate. For now we use fertiliser. But this source of energy is indiscriminate and wasteful. It’s often in powder or liquid form, which means the waste cleaning-up work is done by microbes and algae, not by rats or mice. This leads to infection of ecosystems, deadly algal blooms and eutrophication of lakes, rivers and waterways.
By using agrochemicals, we bypass the positive role that smaller animals like rats and mice play for us, disabling the part of the cycle that allows them to both clean up our waste and maintain the nutrientA substance that contains the raw materials for life. At a chemical level, these are contained inside compounds that are absorbed into the body and essential energy-containing molecules are extracted, so that energy can be transformed into other chemical processes that use the energy for living. More and energy cycles we need to survive. Today, the greatest energy patches that remain are among our crops and housing. We’ve created these. We’ve become the dominant patch-forming large mammal. Which is why we see rodents so often. They thrive in our waste.
Hence, just because we see rats and mice, doesn’t necessarily mean they are bad for us. It stands to reason we should be cautious but without overlooking the positive role they also play. When we reach for science to remove the threat altogether, we risk replacing it with a vaccum that nature abhors.
Will rats take over the world?
The Zalasiewicz rat thought experiment surmises that rats will eventually take over the world. It does indeed seem to be a double-edged sword. Easter Island might have eventually been deforested entirely by rats. Australia’s Lord Howe Island is enjoying a renaissance of native vegetation following the eradication of rodents introduced by introduced to Lord Howe Island in 1918 when the cargo ship SS Makambo ran aground.
But there are places where rats were never native and others, like Australia, where rodents have always been the predominant small fauna. Or South America, where rats (Capybara) are the size of Alsations!
So while eradicating rats from remote islands serves one purpose, we also may need to learn to live with them elsewhere. Ironically, it’s not rats that cause an imbalance in rat numbers, but the predominance of humans at the expense of all other animals. The more we upset wildlife in the balance, the more advantage we give the rats.
Living with rats
If you have rats it means one thing. You have an excess of waste around your land or property. But that’s normal. Poisoning however, merely exacerbates the problem, by leaving more waste behind, building an ever-increasing risk of more rodents leading to other risks. If you’re experiencing more frequent rodent plagues, it means the health of your entire landscape is out of balance.
The negative aspects of living alongside rats, meanwhile, is overinflated by media and scientists. It presents a false sense of alarm, ill-founded given the low risk of threat and the corresponding benefits. The fact remains, rodents are here to stay; humans are more likely to spread our own society-risking diseases; and any effort to eradicate rodents simply makes things worse.
After recent mouse plagues in Australia, the state and federal governments allowed the widespread use of second-generation rodenticides. However, everything we already know about farm pest management tells us this solution isn’t even close to the right thing to do. Small numbers of predators can have a huge impact on suppressing rodents, which is especially useful when rodents can erupt into plague numbers, but using poisons is putting these nature-based solutions at risk
– extract from How to Survive the Next 100 Years.
So, what about the rats? Take them away and we live in our own decay. They are part of humanity’s creation story. We still depend on them and they are here to stay. We should be more thankful for all the rats.
