The largesse of wildlife available in Africa is largely limited to that continent, but what if it wasn't? Imagine a Europe where mammoths and woolly rhinos roam northern Scandinavia, Iberian wolf packs hunt aurochs and brown bears swagger through the Dolomites. If it weren't for the ascent of mankind, the entire world would still look like the Serengeti, a galloping, roaring, thunderous paradise of bloodshed and birth, terror and triumph, as a recent study spells out in living color.

An African safari represents the highest form of interaction with terrestrial giants remaining in the world. The smell of sunlight on acacia leaves and sprawling vistas of ancient beasts going about their daily dramas invoke sublime memories of our shared past and an uneasy feeling of recognition. You somehow feel that you have been here before.

In a recent interview, Faurby told me that his paper , published in Diversity and Distributions, affirmatively "showed that the results strongly suspect a human causation of the extinction of the megafauna. As part of this paper me and [co-author] Jens-Christian Svenning attempted to figure out where these extinct species would have been today if they did not go extinct."

Modern Africa is the last stand of the megafauna that without humans would still cover the planet—a besieged refuge now witnessing the death throes of these final survivors of a world before us.

"The fact that the greatest diversity of large mammals is found in Africa reflects past human activities, and not climatic or other environmental constraints," said lead author Dr. Søren Faurby, an evolutionary biologist from Aarhus University, Denmark, who is now with the Museum of Natural History in Madrid.

The study makes amply apparent the extent to which we have impoverished the world during our brief existence on it. Dr. Svenning, a biologist with Aarhus University, said that "Northern Europe is far from the only place in which humans have reduced the diversity of mammals—it's a worldwide phenomenon. And, in most places, there's a very large deficit in mammal diversity relative to what it would naturally have been."

According to Faurby, this is the "first estimate of how the mammal diversity world map would have appeared without the impact of modern man." The research is a data-driven portrait of mammalian species, both living and those that went extinct within the last 130,000 years, as they would be naturally present across the landscape if humans had never arrived to throw a wrench in the works.

"Most safaris today take place in Africa," Faurby said, "but under natural circumstances, as many or even more large animals would no doubt have existed in other places, notably parts of the New World such as Texas and neighboring areas and the region around northern Argentina and southern Brazil. The reason that many safaris target Africa is not because the continent is naturally abnormally rich in species of mammals. Instead it reflects that it's one of the only places where human activities have not yet wiped out most of the large animals."

The world maps assembled by the researchers graphically illustrate how things would look absent our merciless predatory instinct, with much greater distribution and diversity of large mammals across most of the planet. Note the extraordinarily high levels in both North and South America, continents that today are relatively drained of large mammals—the few wolves and grizzly bears we've allowed to live as scattered survivors would be dominant predators across most of the West, pursuing camelids, bison and giant ground sloths across a Great Plains without a grain silo in sight.

But even there the seeming richness is somewhat illusory, a shadow of what once existed. There are dozens of species of antelope in Africa, for instance, but only two African elephants: the familiar African elephant (Loxodonta africana) and the forest elephant of West and Central Africa (Loxodonta cyclotis). Seventeen of the nineteen species of the elephantine order Proboscidea went extinct during the late Pleistocene, the last Ice Age when modern humans erupted from Africa, leaving us with only the African and Indian elephants surviving today. Today, in Africa and southern Asia, there are a grand total of three species of survivors.

Of particular note here is the loss of enormous terraforming and nutrient cycling capacities of megafaunal mammals (those weighing > 44.5 kg), the earthly titans we extinguished thousands of years ago from almost everywhere but sub-Saharan Africa.

European colonists were dumbfounded by the biological richness of the Western Hemisphere, as indeed they should have been given the plundered paucity of the Old World since the Neolithic era's advent of agriculture and urbanization and the decimation of native ecosystems. But the splendor that greeted colonists in North America was still only an echo of its prehistoric condition, in which human activity and climate change both contributed to a collapse of Pleistocene megafauna.

Darwin posited that species compete with each other less when they're less related; those animals possessing similar anatomies, foraging patterns and habitats are more likely to spar over the same resources. Darwin's hypothesis can "also be seen by tabulating the diversity of different continents," Faurby told me.

"The megafauna of South America belonged to nine different orders, ranging from: Carnivora (carnivores) and Cetartiodactyla (a sprawling group of even-toed ungulates including cattle, deer, camels, pigs, goats and sheep) to Perissodactyla (odd-toed ungulates such as zebras, hippos and tapirs) and Proboscidea (elephant relatives)," he said. "This indicates a high level of biodiversity in prehuman South America, where many different mammalian orders could exploit a varied landscape without detrimental competition."

Today, Faurby continued, "the megafauna of Africa 'only' belong to six orders: Carnivora, Cetartiodactyla, Perissodactyla, Proboscidea, Tubulidentata (the aardvark) and the primates. It is possible that this lower ordinal diversity could potentially be a cause of why there is such high diversity in the New World."

It's like reassembling a puzzle with most of its pieces buried and forever lost

In other words, there are fewer different kinds of large mammal species in Africa today compared to prehistoric South America in the past because of interspecific competition for the same limited resources in modern Africa—limited due to human encroachment, land conversion and direct take in the form of hunting and, today, poaching and wildlife trafficking.