Many times the tertiary consumers are not at the top of the food chain. There are also organisms that prey on them. The organisms that prey on and eat tertiary consumers are called quaternary consumers.
These are on the fifth trophic level in a food chain. These organisms are often the top predators, or apex predators, in the ecosystem. These organisms do not have any natural enemies in the ecosystem.
What is Quaternary Consumer?
A quaternary consumer is an animal that consumes at the very top of the food chain, they are frequently the top predators in their environments, and they prey on tertiary consumers. Polar bears, hawks, wolves, lions, humans, and sharks are all examples of quaternary consumers, as are other large predators.
A food chain picturing a lion as a quaternary consumer starts with a mouse that consumes grass as its initial food. Afterward, the mouse is consumed by a rabbit, who becomes the rabbit’s secondary consumer. In this case, the rabbit is consumed by a jackal, who serves as the tertiary consumer, and the lion then consumes the jackal, thereby elevating him to the position of quaternary consumer.
In this terrestrial food chain, the hawk is the quaternary consumer that feeds on snakes, the tertiary consumer. It also happens to be the apex predator of the food chain.
Similarly, in the ocean food chain, large sharks are the quaternary consumers that feed on smaller sharks, the tertiary producer.
Key Notes:
Quaternary consumers are animals that occupy the highest trophic level in a food chain.
- Quaternary consumers are at the top of the food chain called Top carnivores or apex predators and feed on tertiary consumers.
- Quaternary consumers are typically large and powerful animals, such as sharks, and eagles.
- Some of them feed on both plants and animals and are called omnivores like human beings.
- They play an important role in regulating the populations of other animals in their ecosystem.
- Quaternary consumers are relatively rare in most ecosystems, as there are usually fewer of them than other types of consumers.
- They are often at risk of extinction due to habitat loss, hunting, and other human activities.
- They are not usually killed by other organisms and occupy the topmost trophic level in an ecosystem.
- They are often used as indicators of ecosystem health and biodiversity.
Why are Quaternary Consumers So Rare?
Because they are at the top of the food chain, they are usually larger animals. Since they are larger they also need to eat a lot of food to stay alive, so usually there are less quaternary consumers in an ecosystem than other animals.
Going back to the first example, an ecosystem would have way more mice than it would have leopards. Otherwise, the leopards would not be able to sustain themselves.
These top-tier consumers receive very little of the original energy in a food chain. Remember that with each step of the food chain, only 10% of the energy from the organism being eaten is transferred to the organism eating it.
For this reason, higher-level consumers have to eat large quantities of food to stay alive. The diagram below demonstrates these energy transformations.
Examples of Quaternary Consumers
Some other typical quaternary consumers found in different terrestrial and aquatic food chains are listed:
- Eagles
- Lions
- Tigers
- Polar bears
- Sharks
- Crocodiles
- Sharks
- Large whales
Do All Ecosystems Need Quaternary Consumers?
Not all ecosystems need quaternary consumers. For example, in a savanna ecosystem, antelope eat the grass, and lions eat the antelope.
This food chain stops at the secondary consumer. The lion is still an apex predator because there are no predators that routinely feed on lions. But the lion is not typically a quaternary consumer, because the bulk of its diet consists of primary consumers.
Quaternary consumers are rare because there is just not enough food available at the top of the food chain. At each trophic level, energy gets lost.
When an antelope eats grass, it uses only 10% of the energy from the grass to grow and maintain its body.
The rest of the energy gets lost as heat. Then, when a lion eats an antelope, it again uses only 10% of the energy.
Therefore, it takes 10 times the amount of grass to feed a lion as it does to feed an antelope.
This is why, in any ecosystem, you will always find more primary consumers than secondary consumers, and more secondary consumers than tertiary consumers, with quaternary consumers being even rarer, if present at all.
Another reason why quaternary consumers are rare is that predators often avoid eating other predators.
For example, a study looking at the carcasses of mammalian predators found that scavengers, especially other mammals, tended to avoid predator carcasses, while they were abundant in mammalian herbivore carcasses.
Similarly, while vultures will feed on mammalian predator carcasses, they avoid carcasses of other vultures. This is probably to avoid diseases and parasite transmission.