There are reptiles like lizards and geckos that can break off their tails to escape from a predator.
It's a short-term sacrifice, because eventually, they can grow back a new one.
Humans can regenerate some of their cells, too—including those in organ tissue, like the liver.
I have a friend who burned the palm of her hand pretty badly once on a hot pot handle; but after it blistered and calloused over, the damaged, dead skin eventually peeled away, revealing a whole new baby layer of palm skin underneath.
The human immune system is pretty incredible, because it can heal the body before you even know something is wrong with it. We're constantly exposed to infections of all sorts—bacteria, viruses, fungi, parasites—but we're not doomed to become ill every time because our bodies can heal themselves.
I'm hoping our brains can heal themselves, too.
I'm hoping my heart can heal itself. I don't think anybody else can heal it.
In the Ancient Bristlecone Pine Forest, those trees have to withstand a lot of perils: wind, weather, and a climate dry enough to occasionally burst into flames.
And yet some of them still last thousands of years, thriving in the harshest of conditions, growing in the driest of soils.
Parts of the trees may die off, their bark falling off and the wood underneath becoming twisted, while other sections still thrive.
A dead limb doesn't bring them down. They still manage to pollinate (by wind) a couple times a year...
...and produce these huge pine cones with their tell-tale spikes, a dead giveaway to the "bristle" cone variety of tree.
Their secret to longevity seems to be in the sap, which is often sucked out by a variety of woodpeckers. Any wounds they create in the surface of the tree while feeding off of the sap are immediately filled in by the sap, which seals the wound off from infection so it can grow back, leaving nary a scar.
On our trip to the forest, we watched the process in action, as a park ranger demonstrated how to "core" one of the bristlecone trees in order to determine its age.
He screwed a thin, hollow tube into the side of the tree trunk and then slid it out—warning that if it stayed in there too long without turning, the sap would start sealing it in place.
Soon, the sap will fill the entire hole to facilitate the regeneration of pine and bark. In fact, its own natural process works better than if Ranger Dave had closed up the hole himself or tried to patch it somehow, which bears the risk of trapping a dangerous fungus inside.
You just have to give it time, and let the tree do its thing. And when you come back in a few weeks—or a few thousand years—you won't be able to tell where it's been sucked or cored or otherwise marred.
Of course, I'm a lot more delicate than that. I'm still pockmarked from a sixth grade bout with chicken pox. My left knee has layers upon layers of scarring from all the times I've taken a tumble on it (most recently just this past February). I've got what seems to be a permanent sunburn on my arms and chest.
And I'm not very good at hiding the fault lines in my heart. Someday they're going to rub together the wrong way, and the resulting eruption will do irreparable damage.
Sure, I've been glued back together—like a broken vase or china doll head. Even if you can't tell who or what has pecked at my wood, there's no denying that it has happened.
I've been burned and gutted and sapped dry. And you can tell just by looking at me. I wear my scars on my sleeve.
But maybe the scars don't mean that I'm not healed. My new tail might look a little different than the old one, or than the rest of my body, but it still works as a tail.
And if I have to sacrifice it again in the face of danger, hopefully I've got another one just waiting to grow back in its place.
Photo Essay: Ancient Bristlecone Pine Forest
The Path of Least Resistance