Are Squirrels Omnivores? (Or Are They Primary Consumers?)

Squirrels are small rodents, with long tails and include tree squirrels, ground squirrels, chipmunks, flying squirrels, marmots, and prairie dogs1. Squirrels are indigenous to the Americas, Eurasia, and Africa.

Squirrels are omnivores (secondary consumers) and not herbivores (primary consumers) as most people think. This is because they eat a small number of insects and other small animals in addition to their mostly plant-based diet.

Their diet is mostly made up of berries, fruits, nuts, and fungi but they will occasionally eat insects, eggs, worms, and baby birds or reptiles2, 3.

Squirrels have large incisors, especially adapted for breaking open and eating hard nuts and acorns. Their teeth continue to grow throughout their whole life to prevent wear and tear2.

Squirrels cache food throughout the year, especially during autumn, in preparation for the winter months, when food is scarce.

Why are squirrels important to the environment?

Squirrels food-caching activities play an important role in dispersing the seeds of trees such as acorns and pines.

They often forget where they cache their food, and these nuts then either become food for other animals, or they germinate.

Additionally, when they eat fruits and nuts, the seeds pass through their digestive system and are then deposited in new areas, which help to promote plant growth in different areas.

Squirrels also help to control the plant populations by eating their seeds and fruits. Squirrels are found in a wide variety of habitats, from deserts to rainforests.

In all these environments they play an important role in the ecosystem.

Are Squirrels Carnivores, Herbivores or Omnivores?

Squirrels, like many other rodents, are omnivores since they eat both plants and animals.

While rodents, as a group, are often considered herbivorous, and their long incisors seen as an adaptation to feeding on hard nuts and grains, most rodents are opportunistic omnivores, and some are specialized insectivores.

Squirrels are really not much different from that of mice, gophers and groundhogs in their dietary preferences. Although they do have a proclivity towards nuts!

The specialized teeth of rodents happen to be well suited to an omnivorous diet, since the incisors are just as good at grabbing and killing insects as they are at breaking open nuts.5

Although squirrels can eat insects, their favorite meal will always be nuts!

Another good thing about nuts, is that they can be saved long term for winter!

What Type of Consumer is a Squirrel?

As primarily herbivores, squirrels are considered primary consumers.

Generally, herbivores are primary consumers, omnivores secondary consumers, and carnivores tertiary consumers.

Therefore, when squirrels eat insects or other small animals, they become secondary consumers.

Are Squirrels Autotrophs or Heterotrophs?

Squirrels are heterotrophs because they eat other living organisms. Autotrophs are producers and heterotrophs are consumers.

Autotrophs include plants, algae and bacteria that can photosynthesize. Practically no animals are autotrophic because animals do not get their energy directly from the sun like plants do.

Can Squirrels be Considered Decomposers?

Squirrels do not eat dead or decaying matter and are therefore not decomposers.

On the other hand, the bacteria in the guts of squirrels play a very important role for their digestion and these microorganisms may be considered true decomposers.

When squirrels hibernate, their gut bacteria break down urea molecules into ammonia, using a special enzyme that animals cannot produce4.

Microbes then use the ammonia to make protein, essentially recycling nitrogen in the body. This process keeps squirrels strong during their long winter fast.

Where are Squirrels in the Food Chain?

Squirrels are low down on the food chain, just above the plants that they eat. They are placed on the second trophic level of the energy pyramid (producers, like plants, make up the first trophic level).

Squirrels are secondary consumers when they eat insects.

However, when they eat eggs or insects, they move to a higher trophic level. They also serve as a meal to many predators, making them a very important part of the food chain.

What Animals Prey on Squirrels?

Squirrels are prey for many animals, including birds of prey, foxes, coyotes, snakes, raccoons, and bobcats.

In urban areas, squirrels also get preyed upon by domestic cats and dogs.

Conclusion

In this blog post we have looked into the dietary preferences and feeding habits of the squirrel.

Squirrels play an important role in their ecosystem, both as seed dispersers and as a source of food for predators. Despite eating mostly plants, they are opportunistic omnivores, like many of their rodent relatives.

Squirrels are also very important for our ecosystem, mostly as primary consumer eating nuts and plants.

They are also important for controlling the numbers of other animals and plants in the ecosystem by eating their seeds and insects.

References

  1. Musser G. 2020. Squirrel. Britannica.
  2. Bradford A. 2016. Squirrels: Diet, habits & other facts. Live Science.
  3. Massachusetts Department of Wildlife and Fisheries. 2022. Learn about squirrels.
  4. Cary HV, Regan M. 2022. Gut microbes help hibernating ground squirrels emerge strong and healthy in spring. The Conversation.
  5. Landry SO. 1970. The rodentia as omnivores. The Quarterly Review of Biology. 45(5): 351-372. https://doi.org/10.1086/406647