Wild elephants require between 250 to 500 acres (1 to 2 square kilometers) of land per individual to forage, with some wide-ranging herds covering up to 30,000 square kilometers. Because they consume hundreds of pounds of food daily, they rely on massive territories to survive without stripping ecosystems bare.

Human land usage varies drastically depending on how it's measured—from direct living space to the total ecological footprint required to sustain a lifestyle. Globally, humans use about 1 to 3 acres of agricultural and built-up land per person, though sustaining the average American lifestyle requires nearly 24 acres per individual.
Land usage per individual can be broken down into three main categories:
Direct Footprint (Cities & Towns):
Actual built-up areas (cities, roads, infrastructure) make up less than 1% to 3% of the Earth’s land surface. If divided equally, every person on Earth would have about 0.05 to 0.1 acres (~2,100 to 4,300 sq. ft.) of physical living space.
Agricultural Land (Food): Producing food is our largest land-use category, occupying about 38% of Earth's total land area. On average, it requires about 1.2 to 3.7 acres per person to sustain the global diet. This heavily depends on the diet, with meat-heavy diets requiring significantly more acreage than plant-based diets.
Ecological Footprint (Resource & Carbon):
When accounting for the land and forests needed to absorb waste and produce energy, an individual's footprint explodes. While the global average is around 7 to 8 acres per person, an average American footprint requires about 24 acres per individual to sustain that specific consumption


From above: 250 acres per elephant versus 24 acres per human, a factor of about 10. So, I admit that that is not quite a factor of 1 to 1, but the difference shows just how much land is used by humans. So 10 billion humans living at American standards of living would use about as much as one billion elephants, which Earth could not possibly sustain.