The Earth is 4.543 billion years old, and during that time, it has seen the rise and fall of some truly gargantuan species. In the age of dinosaurs, which spanned an impressive 186 million years in the Mesozoic era, we saw the rise of Titanosaurus, which reached an estimated 59 metric tons.
When dinosaurs died out around 66 million years ago, as a result of catastrophic asteroid impacts, the world began to see the rise of a new hegemony, the kingdom of Mammalia. Across the globe, mammals rapidly diversified from small, hardy rodents to some impressively sized creatures.
In prehistoric America lived the Giant Short-Faced Bear, which was estimated to weigh 2 tons; further south, a 3-ton Giant Sloth made its home. In fact, prehistoric Earth was full of large mammals, including a 90 kg hedgehog! Kingdom Mammalia also birthed the largest animal to ever exist, which still roams the waters of the world today: the blue whale.
Sadly, many continents have lost their megafauna as a result of climate change, human hunting, or a combination of many factors. Africa is one of the last places on Earth that still hosts some truly impressively sized mammals, including hippos, rhinos, and giraffes. It is also home to the largest living terrestrial animal, the African savanna elephant.
How big is an elephant?
On average, an adult African elephant weighs about 5,443 kilograms (12,000 pounds), surpassing any other land creature. Even female elephants, typically smaller, often weigh between 2,268 and 6,350 kilograms (5,000 to 14,000 pounds).
Size encompasses both weight and height. African elephants can also reach some impressive heights, with the average height around 10.5 feet. Complementing this remarkable stature, their trunk extends up to 7 feet in length, enabling them to access vegetation situated high in trees, rivaling even the reach of giraffes.
The largest elephant ever recorded was an adult male African savanna elephant. He weighed nearly 11,000 kilograms (24,000 pounds) and stood nearly four meters (13 feet) tall.
Why did elephants evolve to be big?
To understand why elephants needed to grow so large, we must address the environment they lived in and how it changed over time.
The earliest known ancestor of the modern elephant was Eritherium, which lived around 60 million years ago. It was a fox-sized proboscidean, with no trunk, weighing approximately 5 kg.
When the Eocene arrived (around 56 to 34 million years ago), elephant ancestors lived in a lush, wet coastal environment with plenty of trees, rivers, and plants to sustain a larger body size. However, they faced competition from other Afrotheres, including rhinoceros-like Arsinoitheres and rodent-like hyraxes, all vying for food. Predators like dog-sized hyenodonts and water-dwelling crocodiles and whales also posed significant threats.
To survive, these early elephants grew bigger, resulting in species such as Paleomastodon and Phiomia, with large heads, tall bodies, and long snouts with short trunks and tusks for better feeding range.
By the Oligocene and Miocene, the environment cooled and dried, favoring taller trees and grass. Growing even bigger helped elephants avoid predators and reach food in higher places. Predators like Hyainailouros and Megistotherium, essentially large canine-like creatures, also grew larger, intensifying the need for size.
By the end of the Miocene, giant predators disappeared, but the large size and long trunk remained advantageous. Elephants began to outcompete other herbivores with their digestive efficiency and ability to reach food at different heights.
Unless massive droughts or a new super predator emerged, the elephants’ evolved traits secured their dominance across Africa and Asia. This was the case for many years, particularly in Africa, where elephants began to dominate the continent. In the 1500s, there were an estimated 25 million elephants in Africa. Unfortunately, the elephant’s dreaded super predator did arrive, with an unquenchable thirst for ivory.
Widespread hunting across the continent to fund the global ivory trade brought the once enormous population of elephants down to below 300,000 by the mid-1990s. It is only with recent conservation efforts that elephant populations have begun to increase again.
Conservation Challenges
Elephants, as we know, did not just evolve to be huge; they are also socially complex and accomplished problem solvers. Although this contributes to why we should persevere to protect these amazing creatures, it also contributes to a number of conservation challenges.
Firstly, brains backed by bulk make it very difficult to keep elephants out of crops, and for many farmers living in close proximity to elephants, the results of a crop raid can be devastating, destroying livelihoods and taking lives. This is a challenge faced by many across Africa and also in Asia.
At Tsavo Trust, one of our core missions is to try to reduce the chances of human-wildlife conflict. One way we do this is by providing farmers with the means to protect their crops and themselves. The 10% fence plan, funded by BIOPAMA, has been extremely effective in this regard and has reduced crop raids by 100% since its installation.
Elephants have evolved to be among the largest land mammals on Earth due to a combination of environmental changes and ecological pressures. Their immense size and long trunks allowed them to access a diverse range of food sources and avoid predators. Despite historical declines due to human hunting for ivory, conservation efforts are helping to stabilize elephant populations. However, challenges remain, particularly human-elephant conflict. Organizations like Tsavo Trust are crucial in mitigating these issues, ensuring that these magnificent giants continue to thrive in their natural habitats. The story of the elephant is a testament to nature’s resilience and the importance of ongoing conservation work.