Are Humans the Most Successful Species on Earth?

Human technology has advanced amazingly over the past 200,000 years. Human technology started with spears. A geologically short period later, humans are creating self-learning software termed artificial intelligence, that blurs the line between human creativity and algorithmic thinking. In those 200,000 years, humans have learned a great deal about the Earth's history, the laws of numbers, and built machines that can take humans to the moon. Only recently has science started to reveal the consequences on the planet of human actions such as deforestation, industrialisation and the production of enormous amounts of plastic and clothing. Science is also behind on non-human earth-life life. The great majority of the ocean floors remain undiscovered, which leads experts to say that currently more is known about the moon than about the deep ocean (Haugan, 2015). Additionally, humans have only recently started labelling other animals than themselves as intelligent, indeed, humans consider themselves the most successful species on Earth. In the famous books Homo Deus and Homo Sapiens, by renowned historian Yuval Harari, the author argues that the only reason humans are so successful is their unique ability for complex communication. Though other animals, including dolphins, whales and other species can communicate with each other, their means of communication are significantly less complex (WDC, n.d.). Both books are eye-openers as to how the history of human society has shaped the current and possible future ways of thinking, and they both promote the idea that humans are the most successful species to have ever roamed the planet. There are however animals that challenge this theory, such as the animal that is the subject of this article, the ant.

Ants first appeared roughly 150 million years ago, and are still around to this day (Bradt, 2006). This means that ants were around together with the dinosaurs, and survived the comet that made the giant reptiles extinct. Through this period, ants continuously adapted to their changing environments and have become immensely diverse. So diverse, that it is estimated that 16,000 different species of ants are currently roaming the Earth (Schultheiss et al., 2022). In comparison, there are about 5,500 mammalian species (Burgin et al., 2018). For every human, there are an estimated two and a half million ants (Archie, 2022). The fact that ants have been able to survive and adapt for such a long time, and have become so diverse, challenges the view of humans being the most successful species on the planet.

Figure 1: Besides having been around for such a vast amount of time, ants are also considered to be a very successful group of animals given their geographic diversity. They now appear practically everywhere on the planet (Schultheiss et al., 2022).

Some insects are known to be able to make complex communities, based on highly sophisticated communication. Bee hives, for example, consist of thousands and thousands of individuals. Some bees venture out for food, and once returned, rhythmically start to wiggle. The dance incorporates information about the distance, whereabouts and quantity of the food source. This truly fascinating behaviour has been studied since the 1960s, and yet a lot remains unknown (George & Brockmann, 2019). Ants have an equally interesting way of communication through the shedding of chemicals called pheromones. Although they sound like this class of chemicals could be part of the same family as hormones, they most certainly are not. Insect pheromones are complex organic molecules that insects may spread as means of communication and have no human analogue (YPTE, n.d.). Ants have found a highly optimised way to run colonies incredibly efficiently, using this means of communication. When a food source nearby is found, pheromones are shed that will order more ants to go towards the food source (Adams et al., 2020). The division of labour in ants relies on pheromone communication too, although genetic factors also seem to play a role (Glastad et al., 2020). When threatening ants, or other species, are in sight, the first “scouting” ants run back to their colony and shed certain pheromones that make all fighting ants of the colony ready for a fight.

Communication is not human-specific. Yes, humans have developed languages through which they can communicate enormous amounts of information, more than any other form of communication in the animal kingdom can. The concept of communication, however, is nothing new, as shown by these tiny insects that have been around for over 150 million years (Bradt, 2006). Another of Harari's claims is that humans are such special creatures because we domesticate animals and grow crops, thus humans interact with many other organisms for their own benefit. Even our ancestors, thousands of years ago, manipulated animal behaviour for their own use. It turns out, however, that this behaviour too, is not human-specific, and that this ability is shared with ants. Ants often go out to forage for food. Many species, however, also enjoy a stable food source nearby. To that end, ants grow their own fungus, which transforms plant material into food for ants. The leafcutter ants, which are a group of 47 species, are the most well-known example of this fascinating symbiosis (Handwerk, 2017). This interaction between the fungus (of the Lepiotaceae family) and ants has been going on for so long, that both species completely rely on each other. As a result, the domesticated fungus does not appear anywhere in the wild. Moreover, when ants make a new colony, they bring a little of this fungus to ensure a stable food source for the new colony (Glastad et al., 2020). More complex still is the domestication of another organism: the aphid. These aphids are tiny insects that eat plants and are housed by ants in a certain part of the colony, where they are fed plant material (Ivens et al., 2012). These aphids eat the food graciously, and as they digest, they produce sugar in the form of “honeydew”, which ants ingest as if it is milk. For the aphid to release this precious resource, the ant simply has to stroke the aphid’s back, and the ant will be fed (Ivens et al., 2012). Ants lack much of the brain capacity that makes humans human. Nonetheless, the behaviour that they show is immensely complex. Their communication system is practically flawless, and even complex interactions that many consider unique to humans, are shared with ants. This even extends to violence, or rather, war.

Figure 2: After scratching an aphid on its back, the ant receives a droplet of honeydew (Hearts Pest Management, 2019).

As a result of their 150 million years of evolution, there is enormous diversity among ants. This means that often when different species run into each other, they do not consider each other friendly. Instead, they may recognise each other’s pheromones as aggressive. Another consequence of this variability is that many different ant species have many different hunting techniques. Some ants, including the marauder ants, stick into populations of a few thousand and are continuously foraging for food that includes small animals. Although they do not inhabit an enormous nest like other species do, their colonies are fascinatingly well-organised. When attacking prey, or other enemy ants, the smaller, more rapid ants run to the front line to slow down the enemy, winning time. Although many may die, this tactic stalls the enemy, so that the larger and stronger marauder ants will deliver the death blow (Moffett, 2011).

Other ants are much more territorial. The Argentinian Linepithema humile ant came to California on cargo ships. When they arrived, there were no competing species, which allowed them to spread incredibly rapidly. They now make up a so-called supercolony that has territory between San Francisco and the Mexican border. This enormous colony supposedly consists of one quadrillion (1 000 000 000 000) ants. There are now competing species, however, that practically wage war against L. humile. It is estimated that this war has been going on for a few centuries (Moffett, 2011).

Figure 3: Ants fight brutally. Some species may completely rip their enemies apart, even if they are much larger and stronger (Dpreview, 2013).)

Some ants are particularly brutal in war. Some of their actions in war, were they committed by humans, would be classed as war crimes. Article 6 of the 1945 IMT Charter (Nuremberg) provides that “deportation to slave labour or for any other purpose of the civilian population of or in occupied territory” is a war crime (International Committee of the Red Cross, n.d). Protomagnathus americanus, a very aggressive ant species, raids ant colonies of other species. In these raids, they kill the adults and take all the larvae to their own colony. When these larvae grow, they take over a submissive role, meaning that they live to serve their abductors. Sometimes, through a mechanism not very well understood, the slaves may start rebellions, killing large numbers of the slaver ants (Yong, 2009).

Every day, many ants die as a result of their ability to wage war. Though these actions may seem brutal, it attests to how smart ants are and how well they work together. Although they do not seem to be intelligent individuals, their complex collaborations have given rise to concepts and mechanisms that were thought to be unique to Homo sapiens. This is the case not only for (territorial) war but also for domestication and even slavery. As it becomes more evident that humans are changing Earth irreversibly, and not necessarily for the better, renowned palaeontologists are starting to more publicly wonder whether humans will eventually go extinct (Wonderopolis, n.d.; Gee, 2021). Given that ants have a head-start of roughly 150 million years, it is unlikely that humans will outlive ants. Perhaps we are not as unique and intelligent as we like to think, at least not in the context of survival. Instead, humans could learn to appreciate other complex lifeforms more, including the ant.

Bibliographical References

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