Examples of tertiary consumers
Did You Know?
Since humans kill (though not necessarily predate on) animals on all trophic levels, humans are considered tertiary as well as apex predators.
Animals that consume carnivores are called tertiary consumers. This is the third level of consumers in a food chain. Plants, which produce their own food, are termed as producers. Herbivores, which feed on them, are known as primary consumers. Carnivores that prey on the herbivores are known as secondary consumers. Larger carnivores that prey on these carnivores are known as tertiary consumers. A tertiary consumer may also predate herbivores, and doesn't necessarily only eat carnivores.

Even though they may seem to be at the top rung, tertiary consumers are sometimes eaten by even higher carnivores. Thus, tertiary consumers aren't always apex predators, but apex predators are necessarily tertiary consumers. For example, a large snake may eat a fox, which is a secondary consumer. This makes the snake a tertiary consumer. However, snakes can be eaten by eagles, which are apex predators. However, it is worthwhile to note that preying on a tertiary consumer doesn't automatically make the predator an apex predator; the snake in the aforementioned example can also be eaten by a mongoose, but a mongoose is not an apex predator.

The term 'tertiary consumer' is relative to a particular food chain, since an animal in the wild eats various types of foods, and can be at varying trophic levels in the respective food chains. For example, a golden eagle can eat rabbits, which are primary consumers, as well as foxes, which are secondary consumers. So, though the eagle is a secondary consumer in the first food chain, it is a tertiary consumer in the second food chain. Thus, the term refers to the trophic level of an animal in a particular food chain.

Having seen what the term stands for, let's look at some examples of tertiary consumers from various ecosystems.
Commonly Seen Tertiary Consumers
Great White Shark
Attacking Shark
One of the most famous and feared tertiary consumers in the world is the great white shark. An apex as well as tertiary predator in the ocean, great white sharks are hypercarnivorous, i.e., virtually all of their food is meat. They kill almost all fish that are smaller than them, including some that prey on other, even smaller fish. They also kill seals, which kill fish and penguins (which, incidentally, also kill fish).
Big Cats
Lion in grass
Indochinese Tiger
Leopard Panther Resting
Jaguar animal
All big cats are tertiary predators, since they kill herbivorous primary consumers as well as carnivorous secondary consumers. However, one of the four, the leopard, is not an apex predator, since it is sometimes killed by lions and tigers, with whom it shares its habitat. Smaller predators such as foxes, badgers, and 'smaller big cats' such as the lynx, bobcats, ocelots, serval are the most commonly killed carnivores. Tigers, in particular, regularly come in contact with Asiatic black bears and crocodiles, and some even specialize in hunting bears. Lions and tigers both come in contact with the leopard, and the smaller cat is almost always killed. Lions may also face off against crocodiles, and jaguars frequently encounter caimans.
Saltwater Crocodile
Crocodiles are the kings of the water. In its preferred habitat, they pack a punch that almost no animal can handle. Crocodiles have some of the strongest jaws in the animal kingdom, and, consequently, some of the most powerful bites. Even large and strong predators such as lions and tigers can't escape crocodiles if they enter the water, though they can overpower crocs if the latter ventures onto the land.
Pythons and Boas
Desert rock python
Though pythons would struggle to overpower predators such as adult crocodiles and big cats, they can easily kill foxes and wild cats. They can also kill juvenile big cats or crocs. Anacondas are known to prey on caimans, which are smaller than crocodiles.
King Cobra
King cobra snake
King cobras are specialist snake-eaters. Since all snakes are carnivorous, king cobras are tertiary consumers. Kingsnakes, which also frequently feed on other snakes, are also tertiary consumers. The 'king' in both names signifies their common diet.
Killer Whale
Killer Whale
Killer whales, or orcas, are the only marine predator that can challenge large sharks. They are intelligent and ferocious killers, and frequently hunt seals and penguins, which feed on fish.
Polar Bear
Polar Bear
The top predator in the Arctic, the polar bear kills fish, penguins, and seals, making it a tertiary predator. The complexity and relativity of the term 'tertiary consumer' is best illustrated by the examples of the oceanic tertiary consumers―the great white shark, the orca, and the polar bear. Due to the presence of multiple aquatic food chains, a fish killed by a penguin may already be a tertiary consumer. If a polar bear eats a seal that has eaten the penguin in question, the bear cannot strictly be considered a 'tertiary' predator, since many more trophic levels have passed in the process. However, this needless complexity in nomenclature is usually ignored, and sharks, orcas, and polar bears are considered tertiary and apex predators.
Desert Sidewinder
Found in the deserts of southern North America, the sidewinder is the perfect example of a tertiary consumer in desert ecology. It feeds on various animals, including rats and spiders that kill insects such as grasshoppers and beetles.
Bald Eagle Flying
All eagles are secondary consumers, since they are carnivorous. However, some eagles go one step further and prey on snakes, foxes, owls, etc., which makes them tertiary consumers. Some hawks and falcons, which also prey on similar prey, are tertiary consumers.
Secretary bird
Secretarybirds are famous for being snake hunters. They kill and eat various reptiles and small mammals. Weirdly, venomous snakes such as cobras and adders are most commonly sought. Adult secretarybirds have terrifyingly strong legs that can break human bones with a single stomp. This formidable weapon makes them near-invincible (adults are almost never preyed upon). They are apex predators, though their young may be eaten.
These were some examples of tertiary consumers found in tropical rainforests, deserts, jungles, snow, and the oceans.