[Note: This is the fifteenth sample from my rough draft of a far from finished new book, Wild, Free, & Happy. I don’t plan on reviewing more books for a while. My blog is home to reviews of 201 books, and you are very welcome to explore them. The Search field on the right side will find words in the full contents of all rants and reviews, if you are interested in specific authors, titles, or subjects.]
Fearless prey was a lucky but temporary windfall jackpot for migrating hominins. Another major asset was our ability to digest a highly diverse diet of plant and animal substances. Because we aren’t fussy eaters, we can survive changing conditions better than many other species. This advantage was greatly expanded by our unique ability to cook foods. We can nourish ourselves in chilly Greenland, steamy Amazon rainforests, and the scorching Sahara. In recent times, humans have also become the top carnivore in marine ecosystems, despite the fact that we don’t even live in the water.
Over the span of millions of years, animal species of all types and sizes evolved time-proven anti-predator strategies for self-defense — flying, fleeing, swimming, climbing trees, diving into burrows, injecting venom, counterattack, camouflage, and so on. These ancient strategies worked fairly well, but not every time. Predators needed sustenance too. Ideally, predators and prey lived in relative balance. This encouraged wild ecosystems to maintain a state of long term sustainability. Perfect! It discouraged population explosions that can become ecological hurricanes. Hooray!
When musk oxen were attacked by wolves, the group backed up together into a circle, butt to butt, with their horns facing outward, and patiently waited for the hungry predators to give up and have a good cry. When raccoons, squirrels, or bear cubs were attacked by predators, they zipped up the nearest tree and giggled at the frustrated killers. These excellent time-proven strategies failed when heavily armed hominins arrived with their deadly projectiles.
For many grassland herbivores, speed was an essential predator defense strategy. Pronghorn antelopes can run for more than 20 miles (32 km). They can flee at speeds up to 70 miles per hour (112 km/h), for up to two miles (3.2 km). Pronghorns originally evolved high speed flight to outrun hungry cats — species that went extinct maybe 12,000 years ago. Today, wolves and coyotes are way too slow. Sadly, ranchers have installed some fencing on the prairie, and pronghorns can’t leap fences. The fence prevents escape, the animals pile up, and enable mass kills.
When bison are attacked by natural predators, grazing stops, and running begins — the whole herd following the leader. Slower animals, like calves, the elderly, and the sick or injured become the main course at lunch time. This strategy worked well for millions of years until Neanderthals and humans organized communal hunts, and chose locations where fleeing herds could be guided into traps or off cliffs. In this situation, follow the leader escapes could be disastrous.
For eons, sea birds, sea turtles, and marine mammals found security by living on islands. This advantage was diminished by the invention of canoes, kayaks, harpoons, and so on. Many of these island animals lived in a way that made them highly vulnerable when hungry aliens washed up on shore. Many had a hard time fleeing or hiding.
Critters that found security in camouflage or concealment became far more vulnerable when hominin hunters set fire to the grass. Excellent camouflage lost its advantage when enslaved dogs joined the hunt. Their powerful sense of smell enabled them to quickly find prey that were difficult to see. Critters that evolved the ability to make high speed escapes became more vulnerable when hunters began riding enslaved horses. When hunters used both horses and dogs, game was far less likely to survive.
Evolving to jumbo size was another very effective anti-predator strategy. Big, strong, healthy, mature elephants, rhinos, and hippos had little reason to fear wild carnivores. Size mattered. Predators preferred to kill their youngsters, because they were less dangerous, and easier to kill. Jumbo size species have far lower rates of reproduction. Wee critters, like mice, bunnies, and insects, are popular items on the menus of many animals. Consequently, they reproduce like champions.
Unfortunately, when hominins adapted spear technology, jumbo size became a serious handicap. Elephants were big, slow, easy to find, and had lots of meat. Hunting large game was energy efficient. Killing a mammoth required far fewer hours and calories than killing a thousand bunnies. Around the world, 50,000 years ago, the land rumbled under the feet of countless megafauna, every continent a Serengeti.
Stephen Wroe summed it all up. Over millions of years, many animals developed anti-predator strategies that were good enough to keep their species in existence. Tragically, the arrival of tropical primates armed with specialized high-tech hunting technology radically altered the rules of predation. Advanced kill power, combined with fearless prey, sparked a revolutionary shift. In the new paradigm, animals had to move beyond traditional anti-predator strategies, and strive to develop new and different anti-predator strategies that were hominin-specific. Species unable to make this transition were more likely to blink out.
Technological crutches enabled our ancestors to become direct competitors with wolves, big cats, and other carnivores. Wherever hominins expanded, they had the ability to destabilize long running ecosystem relationships. Crutches also made us less vulnerable to man-eating predators. Spears enabled our ancestors to better repel the predators that could help keep hominin populations stable and healthy. This rubbished the laws of nature. Imagine rabbits inventing tools that allowed them to kill foxes — soon there might be seven billion bunnies staring at cell phones (gasp!).
Colonizing Snow Country
Obviously, tropical primates evolved to survive in tropical ecosystems, which were warm all year round. By and by, some hominins migrated out of tropical regions, and into temperate ecosystems, which had four seasons, including snow.
When tropical primates began wandering into regions with frigid winters they were confronted with new and serious challenges to survival. They were presented with a painful warning similar to modern highway signs: Wrong Way! Do Not Enter! But, instead of cautiously turning around, and going back to more comfortable lands, some proceeded deeper into the domain of the frost giants, and discovered many super-cool new ways to die prematurely. The game rules radically changed. Warm clothing, protective shelter, new tools, and food storage boosted the odds for survival.
A bedrock theme in this book is that the ecosystems which move through the millennia guided by genetic evolution tend to make transitions in a fairly graceful manner. Ungraceful ecosystem transitions are far more common when the hominin residents naively develop a never-ending abusive relationship with the super-sticky tar baby of cultural evolution and technological innovation.
Japanese snow monkeys slowly and smoothly adapted to a temperate climate via genetic evolution. Humans emerged maybe 300,000 years ago, when the hominin drama was already heavily dependent on cultural evolution (fire, weapons, stone tools, etc.). Our homeland in Mother Africa had a tropical climate, and genetic evolution had provided our species with better heat tolerance. Human genes have not made extensive changes in 300,000 years. We remain able to live happily in tropical lands, but still can’t survive in snow country without a load of prosthetic technology.
Between the Arctic, and the Mediterranean, there were several climate zones — ice, tundra, steppe, and woodland. When the climate plunged into frigid periods, glaciers and ice sheets expanded downward from the north, which compressed the zones to the south. There were times when the ice sheet extended from Scandinavia to northern Germany, and covered most of the British Isles. At times, large areas of France were tundra. The Mediterranean Sea, a large body of warm water, moderated the climate of southern Europe, so the temperature swings were less intense in Gibraltar, and wild foods remained abundant for the remaining Neanderthals.
One indicator of climate shifts is the types of bones found at various time periods in the layers of cave crud. The layers associated with Neanderthals usually indicated warm, moist, woodland or forest. Woodland conditions were identified by the bones of aurochs, red deer, boar, cave bear, leopard, giant deer, and temperate rhinoceros. The ideal weapon for woodland ambush hunting was the thrusting spear, and it remained the perfect tool for 400,000+ years.
It’s important to understand that the more recent sites, which are associated with humans, often indicate steppe-tundra conditions, when the land was cold, dry, open, and treeless. Steppe-tundra conditions were identified by the bones of woolly mammoth, woolly rhinoceros, horse, musk ox, ibex, moose, Artic fox, and reindeer. In steppe-tundra habitat, the wide open landscape had no trees or brush for hunters to hide in. So, their preferred weapon was the javelin, which could kill from a distance.
When humans wandered into the steppe grasslands of Eastern Europe 36,000 years ago (the “European Serengeti”), their tropical bodies were not fine-tuned for freezing weather, nor had they evolved the clever trick of hibernation. Moving into a winter wonderland was something like colonizing Mars. At this point, their choices were: (1) give up and freeze to death, (2) turn around and return to home sweet home, or (3) innovate like crazy and struggle to survive in a hostile climate where large game was abundant.
Aside from stuff like frostbite, winter hunger, and respiratory issues from smoke filled shelters, there may have been significant health benefits to colonizing temperate ecosystems. Our African homeland was tropical, with a climate that ranged from warm to hot year round. Tropical ecosystems have the highest biodiversity of plant and animal species, including the entire spectrum from elephants to microbes. The colder the ecosystem, the lower the biodiversity, because many species have not evolved the ability to survive months of intense cold.
Pathogenic tropical parasites include malaria, schistosomiasis, and sleeping sickness. Some regions in Africa are uninhabitable due to the high risk of sleeping sickness. Tropical viral diseases include yellow fever, and three hemorrhagic fevers: Ebola, Marburg, and Lassa. A warm climate is also home to more species of disease transmitting insects, many of which have poor cold tolerance.
The tropics are home to numerous other species of monkeys and apes, with whom humans are more likely to swap diseases. For example, AIDS is caused by the HIV virus, which is probably a mutation of the SIV virus that is carried harmlessly by chimps. Today, chimps, gorillas, and humans are dying from Ebola. It is likely that tropical diseases had far less impact 50,000 years ago, long before deforestation, bushmeat hunting, agriculture, herding, irrigation, high mobility, and explosive population growth. A later chapter will devote more attention to disease.