Instead of getting our meat from apex predators, humans have mostly hunted big mammals who are only one step away from plants.
But we humans are hungry and our population was growing fast. So even that strategy pushed a lot of species into extinction.
And then we came up with an idea. Instead of relying on wild numbers of animals and searching for berries and nuts, we kept our own animals and grew our own food.
But the laws of biology didn't change. In the process from plants to animals, we still lose about 90% of the energy. So for a long time, meat was a luxury.
So how do you increase the number of cows? By channelling more of the plant energy to the cows.
After the first World War, we used chemicals to force plants to grow faster and bigger. With this trick, it became possible to concentrate more plant energy to our cows, pigs and chickens.
Voila, cheap meat for everyone (in rich countries).
Eating cows is more efficient than eating eagles, but we still lose a lot of calories in the process.
Half of all cereals like maize and wheat are fed to cows, while the resulting meat and dairy only provide 18% of our calories.
Channelling so much plant energy to farm animals leaves less for the wild food chains of the world. Instead of hunting animals into extinction, we are now doing it through farming.
But more importantly, is there enough energy for every human?