For many people living in cities, encounters with large, wild animals are limited to zoo visits. We might watch bears or tigers on live zoo cams, observing their seemingly gentle routines like basking in the sun or enjoying a frozen treat. In this context, the idea of these creatures as formidable predators, potentially even dangerous, can feel distant and unreal. As one anthropologist noted, it can be a “bizarre realization” to understand that humans are not always at the apex of the food chain.
While it’s uncommon for humans to be prey, this doesn’t automatically place us at the top. Scientists have been analyzing global consumption patterns to understand our position in the ecological hierarchy. Their findings reveal a surprising truth: humans are not only far from the top of the food chain, but we occupy a rather modest level.
Understanding the Food Chain
At its core, the food chain is a straightforward concept: a “who-eats-who” system that culminates in the ultimate predator. Beginning in the 1940s, scientists began to develop a more nuanced model using trophic levels. This system categorizes all living organisms—plants and animals—into distinct levels: primary producers, herbivores, and primary and secondary carnivores.
The study of trophic levels, known as trophodynamics, allows scientists to examine the intricate relationships between these groups. It helps them understand how these groups interact, function within ecosystems, and how the presence or absence of one group can impact others.
Recent advancements in software have significantly enhanced our understanding of trophic levels. We now recognize that most animals have diverse diets, consuming multiple types of prey. Modern analytical approaches account for these varied diets, providing a more accurate picture of food chains.
Scientists now consider how interconnected food chains form complex food webs. Within these webs, different trophic levels can exhibit varying degrees of interdependence. Factors that are crucial in one food chain might be less important in another, and dominant elements in certain food webs might be absent in others. These complexities are key to understanding why humans do not rank very high on the food chain.
Read More: Conserving Predators of the Plant Kingdom
Human Position in the Food Chain: Not as High as You Might Think
Humans do not belong to the same category as apex predators like orcas or polar bears. In fact, our trophic level is similar to that of anchovies and pigs.
Scientists typically utilize five trophic levels to classify organisms within food chains.
1. Primary Producers: The Base of the Food Chain
Alt: Lush green forest floor depicting primary producers, plants using sunlight for energy.
Trophic level one, designated for primary producers, includes organisms that generate their own energy and do not consume other organisms. Plants are the prime example, utilizing sunlight and water through photosynthesis to produce energy.
2. Primary Consumers: Herbivores and Omnivores
Level two encompasses primary consumers, creatures that feed on level-one organisms. Herbivores, like cows, exclusively consume plant matter. This level also includes omnivores, which have a more diverse diet consisting of fruits, vegetables, grains, and sometimes meat. Humans, bears, raccoons, and pigs are all examples of level-two consumers.
Trophic levels are incremental, which clarifies how humans can consume pigs yet occupy a similar trophic level. These levels range from 1 to 5.5. Despite humans eating pigs, our significant consumption of non-meat foods places us in level two, although towards the higher end compared to strict herbivores.
3. Secondary Consumers: Carnivores and Omnivores that Eat Primary Consumers
Alt: Sharp-eyed hawk perched on a tree branch, a secondary consumer preying on level two animals.
Secondary consumers are typically carnivores or omnivores that primarily eat other animals, though they might also consume some plant material. Raptors that prey on birds from level two fall into this category.
4. Tertiary Consumers: Carnivores Eating Carnivores
Tertiary consumers represent the next stage in the food chain, comprising carnivorous species that hunt other carnivores. Killer whales, or orcas, are examples of tertiary consumers. They are known to hunt seals and sea lions, which are carnivores that feed on fish, squid, and octopuses.
5. Quaternary Consumers: Apex Predators at the Top
Alt: Majestic polar bear in a snowy arctic environment, an apex predator at the quaternary consumer level.
The highest level, quaternary consumers, is reserved for apex predators like polar bears and orcas. These animals typically have no natural predators within their ecosystems. However, this doesn’t preclude an apex predator from occasionally being consumed by another. The incremental nature of trophic levels allows for ranking these animals at 5.5 to account for instances where apex predators deviate from their typical diet and consume another top-level creature.
Read More: How Do Animals Know What Their Predators Are?
Are Humans Truly Apex Predators? The Reality of Our Trophic Level
Humans are often referred to as apex predators, implying that we sit at the food chain’s pinnacle, free from natural predators. While humans exhibit some characteristics of apex predators, scientists debate whether we truly fit this classification.
In a 2013 study, a team of French scientists sought to pinpoint humanity’s precise position in the food chain, or our human trophic level. They employed the standard trophic level scale of one to five.
Their research revealed that humans rank several rungs below apex predators. Using national data from the U.N. spanning from 1961 to 2009, they examined the food supply of 98.1 percent of the global population.
Humans rely on a diverse diet encompassing fruits, vegetables, grains, and proteins. Our protein sources primarily come from level-two animals like chickens, cows, fish, and pigs. This dietary diversity means humans are only slightly above the trophic level of the level-two organisms we consume. The study concluded that the human trophic level ranges from 2.04 to 2.57, averaging at 2.21.
A trophic level of 2.21 places humans on a similar level to anchovies and pigs. Even countries with higher meat consumption, like Iceland, still scored well below a trophic level of three.
Read More: Did Humans Hunt the Biggest Animals to Extinction?
So, What Animal Actually Reigns Supreme at the Top of the Food Chain?
While zoo animals might lead us to believe that lions or bears are at the apex of the food chain, these large predators are absent from many ecosystems. The “top” of the food chain, therefore, is relative to a specific ecosystem.
Alt: Vibrant starfish clinging to underwater rocks, an example of ecosystem-specific apex predators.
Starfish, for example, are apex predators in their marine ecosystems, but they are irrelevant in freshwater systems like the Great Lakes.
Similarly, human development and agriculture have disrupted food chains in numerous ecosystems. In urban and suburban environments, the removal of traditional apex predators has allowed other animals to ascend to the top. Raptors often become the primary predators in these altered ecosystems.
Therefore, while humans are not near the top of the global food chain, we often inhabit environments where true man-eating predators are confined to zoos or seen only on wildlife webcams. This perspective highlights the importance of understanding food chains within the context of specific ecosystems and the impact of human activities on these delicate balances.
Read More: The “First Predators” Ruled a World Full of Bacteria
