Quick—what’s the largest animal that comes to mind? Maybe you picture a beautiful elephant or a whale. You wouldn’t be wrong since those two animals are very big. But if we take a look at the entire history of the Earth, the elephant doesn’t come close. So, when looking at extinct and currently available species, which animals are the largest?

Patigotitan

Credit: Zissoudisctrucker / CC BY-SA 4.0

Let’s go back in time to the Late Cretaceous period when dinosaurs ruled the Earth. One of the most recent dinosaurs to be discovered is Patigotitan Mayorum and was found in Patagonia, Argentina, in 2014. Patigotitan’s fossilized bones were found on farmland. Once recomposed, scientists estimate that the giant dinosaur was 121 feet long and weighed roughly 76 tons. This massive ancient animal was an herbivore with a long neck that would allow it to rest its head on a five-story building. Scientists believe that during its time, Patigotitan didn’t have any natural predators because it was just too big to attack. If you’re dying to see this ancient animal up close, plan a trip to New York and stop by the American Museum of Natural History.

Blue Whale

Credit: gremlin / iStock

Jumping back to animals that are currently living, the blue whale is the biggest animal and mammal on the planet today. While it technically doesn’t count as a “roaming” animal as our article title suggests, it deserves a mention because it comes in at an average weight of 300,000 pounds and 98 feet long. These majestic creatures live between 80 and 90 years. Officially, blue whales are part of the baleen whale classification and subsist on eating tons of small crustaceans like krill every day. However, the blue whale is currently on the decline and is one of many animals on the endangered list.  

Argentinosaurus

Credit: Warpaintcobra / iStock

Switching tracks, we’re back to extinct animals from eons ago. Argentinosaurus was also discovered in Argentina and belongs to the same genus as the Patigotitan. And like the first entrant in this list, this particular dinosaur is also from the Late Cretaceous period and an herbivore. This lesser-known dinosaur was first discovered in 1989 when an Argentinian rancher mistook a fossilized leg bone for a piece of giant petrified wood. Argentinosaurus is estimated to have been between 98 to 115 feet long and weighed 88 to 110 short tons.

For the curious, Argentina is a major discovery zone for dinosaurs, with over 20 unique species having been discovered throughout the country and especially in a region known as The Dinosaurs’ Valley.

Spinosaurus

Credit: LindaMarieB / iStock

Spinosaurus is another dinosaur that tops the list for largest creatures to ever walk the earth. Unlike the previous dinosaurs on this list, this one was a theropod and carnivore. Scientists know, based on fossil findings, that Spinosaurus lived in Northern Africa and most likely hunted terrestrial and aquatic animals. This dinosaur was first discovered in Egypt in 1912 and is dated to the upper Albian and Upper Turonian stages of the Cretaceous period. In terms of size, Spinosaurus was between 41 to 59 meters long and weighed 7.7 to 23 short tons.

Megalodon

Credit: Warpaintcobra / iStock

Once again, we turn to ancient animals for this list. But this time, we’re focusing on aquatic life. Before SyFy was turning out campy shark movies, the megalodon was really a thing. The word "megalodon" means “big tooth” and refers to a now extinct shark species. This huge shark lived from the early Miocene through the Pliocene periods. Scientists haven’t created a total consensus on which current-day sharks megalodon most closely resembles. Some say that it was a chunkier version of today’s great white sharks while others believe that it was more like the basking or sand tiger sharks. If you want to see just how big of a bite the Megalodon had, stop by its jaw fossil after you say hello to the Patigotitan at the American Museum of Natural History in New York.

Most of the animals on this list are no longer with us (and considering that two of the four extinct animals were vicious predators, this might not be a bad thing). But you can still see the blue whale at zoos or on aquatic tours. And more importantly, you can advocate for conservation so that our largest living animal doesn’t join the others on this list.