An omnivore is a kind of animal that eats either the flesh of other animals or plant products, according to the availability of the food sources. Some omnivore hunts animals and eats their product, like a carnivore, eating herbivore and other omnivores.
Human beings, dogs, cats, crows, peacock, chicken, bears, etc are examples of omnivores.
Omnivore animals (including human beings) come in different sizes.
Kodiak bear is the largest and endangered omnivore. It may grow up to 10 feet tall (3.04 meters) and it weighs up to 1,500 lbs (680 kilograms).
According to the Alaska Department of Fish and Game, Kodiak bears eat grass, plant, berries, fish and the occasional mammal.
The pharaoh ant is the smallest omnivores. According to the University of Michigan, pharaoh ant grows only 0.04 to 0.08 inches (1 to 2 millimetres). They eat eggs, carrion, insects, nuts, seeds, body fluids, grains, fruit nectar, sap and fungus, etc.
Omnivores eat plants and plant products like herbivores, but they do not eat all kinds of plants because of omnivore animal cannot digest some of the substances in grains and other plants that do not produce fruit.
An omnivore has the ability to eat and survive on either animals or plants. They obtain their energy from these animals or plant and they have the capability to digest carbohydrates, protein, fibre and fat, etc.
They are the most flexible eater of the animal kingdom because they eat both plants and animals, according to the availability of the food sources. When meat (flesh) of animal is not available they eat vegetables (plant) and vice versa.
They can eat vegetables and fruits. Some of the omnivore insects in this simulation are pollinators, which are very important for the life cycle of some types of plants. We have several kinds of omnivores to choose from in this simulation, of different sizes.
Omnivore animals in the food chain
Like carnivores and herbivores, omnivores are also an important part of the food chain or food web. As the herbivores and carnivores have maintained the balance of the food chain in the ecosystem, omnivores also maintain the balance of food resources in the food chain of the ecosystem.
Creatures in the food chain or food web are divided into a system called the trophic system. This trophic system includes three levels.
The top-level includes carnivores and omnivores. The second level includes herbivores (animals that eat plant or vegetation) and the lower/bottom level includes living things that produce their own food, like plants.
If one level of the trophic system is removed, all the trophic levels below them will be affected. This is called a “trophic cascade”.
Omnivores maintain both animal population and vegetation growth. If we remove an omnivore species, it can lead to overgrowth of vegetation and an overabundance of any creatures that were a part of the diet.
Digestion in an omnivore animal
Omnivore animals have very distinctive teeth that help in the digestion of their different types of diet.
They often have long, sharp, pointed teeth to cut and rip flesh (meat) and flat molars to crush plant materials (plant products).
The human mouth is the best example. Humans have canine and incisors that bite and rip the food and molars and premolars that crush the food. While most animals have sharper and pointed teeth for tearing and ripping the food materials, the work is the same.
Some omnivores such as chickens have no teeth and they swallow their whole food. The digestive enzyme and hydrochloric acid present in the stomach softens the food swallowed by chickens. Then the foods get broken down in the gizzard, a strong digestive muscle.
Omnivores have different digestive systems than either herbivores or carnivores.
Herbivores may have very complex digestive systems that can include multiple stomach chambers and regurgitating food for re-chewing because plant materials are much harder to digest.
On the other hand,
carnivores have a very simple digestive system because the meat is easy to digest.
Omnivores such as humans have very simple types of the digestive system. Humans have a limited ability to digest certain plant materials. They cannot digest harder materials. The digestive tract sends harder material out as waste.
Why did some animals eat meat or vegetation while others eat both?
This is because of the availability of the food sources at different places. The place has only vegetation/plants, their animal eats them continuously and they became herbivores.
Similarly, where there was the availability of only meat, their animal eats them and they became carnivores and omnivores evolved because of eating both meat and vegetation.