What a long, strange trip it's been. Every step confirmed the truth: that life on earth is not weirder than we imagine: it's weirder than we are capable of imagining. In the course of my journey through the entire animal kingdom I realized that human society would be better if only we were more like vampire bats, and I learned about a six-legged bear that you can boil, freeze and shoot into space without killing it.
I set off to write a book about the entire animal kingdom, a reckless project considering that it contains (conservative estimate) ten million species, hence the book's title. And as I did so I learned not so much about what separates us as what unites us. We humans are animals too: mammals along with rats and dogs and blue whales, sharing the phylum of chordates -- back-boned creatures -- with birds, frogs and fish.
Vast libraries of philosophy across the world offer irrefutable proof that we humans are utterly, utterly separate from the rest of the animal kingdom. Every where you look in the real world you find they're all wrong.
Apes and crows use tools and solve problems, many creatures including honeybees have communication systems that challenge our ideas about language, elephant are aware of death, nightingales and humpback whales compose music, bower-birds are creative visual artists.
We would like to think that humans have a moral dimension that other animals lack: but then we turn to vampire bats. Common vampires live on the blood of mammals, blood-hunting by night and sharing a roost in the hours of daylight.
It's not an easy business: even an experienced bat will have a blank night most weeks, and it gets harder to hunt when you're weakened by hunger. So an empty-bellied bat will return to the roost and beg a meal of a roost-mate: a friend, we would say, if we weren't terrified of sounding sentimental.
One bat will do a favor to another bat who is not necessarily a relation. In other words, pure altruism. And that's how a decent society operates. Our own lives are defined by the small favors we do for others and expect to have done in our turn. It's the basis of a humane society. But it's not just humans who are humane.
The thing that worried me most as I set off on this precarious voyage was that I would find group after group of boring animals with little to distinguish them and little to capture the human imagination. I found I was wrong in about ten million ways.
I realized this in a single dramatic leap when I learned about the water-bears. This is a phylum of microscopic animals: their discoverer thought their shambling gait was rather bear-like. They can be found in prodigious numbers: there can be 25,000 individuals in a liter of sediment. You can find them at 20,000 feet in the Himalaya and at 13,000 feet in the ocean. They live in the tropics and at the poles. They've been found living under 16 feet of ice.
And you can't kill them. If the object of life is to avoid death, these water-bears are the all Animal Kingdom champions. They have failed to die at temperatures close to absolute zero. Boiling is nothing to them: they have survived temperatures of 151 degrees C. They can stand 1,000 times more radiation than humans. They've been shot into a low earth orbit and come back safe and sound.
When things get impossible they have one more trick up their microscopic sleeves: they can shut down and wait for things to get better. They go into a phase called cryptobiosis: hidden life. It's been called the instant coffee phase: they become flecks of almost nothing, and can survive that way for ten years. Then they find a droplet of water and become living things once more.
As I was writing the book I toyed with the idea of making up a few creatures, but soon abandoned it. Partly because no one will believe the real ones I've already got, and partly because nature comes up with stuff that's ten times weirder than I would ever dare to think.
So I traveled though a kingdom in which wasps made human learning possible, where there are sponges made of glass, where animals can form a lawn, where's there's an entire group of creatures that live only on the mouths of lobsters, where there's a sexy jelly called Venus's girdle, in which spiders can make seven different kinds of silk, in which parasites live lives of horrific depravity, where birds invented the Cold War principle of crisis relocation, in which an octopus can indulge in play, and where a female insect can devour seven husbands in a week and vast cities with millions of inhabitants exist far more harmoniously than any human institution ever will.
Life on earth is magnificent, hilarious, ludicrous, horrifying, enchanting, beautiful, ugly, awe-inspiring, disgusting, terrifying, heavenly. It reflects the absolutely ordinary nature of the marvelous and the absolutely marvelous nature of the ordinary. It was the journey of a lifetime... and right now I'm wondering how I can possibly do it again.
Simon Barnes is the author of Ten Million Aliens: A Journey Through the Entire Animal Kingdom (Atria Books/Marble Arch Press).