I’ve been on more than a few nature walks in my time. Bog walks, woods walks, swamp walks, sometimes leading them myself but mostly trailing along with the rest of the group while the naturalist in charge points out interesting features with the calming assurance of a flight attendant indicating the emergency exits.
I love nature walks, but what amazes me about them is how alike they are, each to each, at least here in my pocket of New England. Even though you never know what you will find in the woods, you don’t literally never know. There are reliable performers — organisms that are common enough to predictably find, but unknown enough to provide astonishment when you do find them: oak apple galls strewn on the trail that you pick apart to reveal a larval wasp at the center, like the prestige of a magic trick; water-dwelling caddisfly larvae that build homes for themselves like tiny log cabins out of sticks, with gravel and mud for the chinking. I was 10 when I first found one, and I remember feeling my vision tunnel and my classmates’ voices grow muffled as I crouched by the culvert watching it.
Red-backed salamanders are reliable performers like this. Turn over a couple of rotted logs and it’s possible you’ll turn up an equal number of red-backed salamanders. They are common in the extreme. In some American woodlands, their population density approaches 1,000 salamanders per acre. As a result, they are a go-to for naturalists leading walks. It feels almost cheap to kick over the first dead wood you see and come up with stub-legged creature, glistening like a gummy worm. If you’ve been on even one nature walk, you may have heard your guide trot out the astonishing statistic that red-backed salamanders outweigh the biomass of all the other vertebrates in the forest. Pile up all the deer, and foxes, and ovenbirds, and weasels, and squirrels, and the pile of red-backed salamanders from the same woods will be heavier.
The truth the nature walk leaders might not be pleased for you to know is that you don’t need them to help you find these creatures. Red-backed salamanders don’t just live in the deep, distant woods. If you have a woodpile in your yard (and if you don’t, you should), then you have these beasts in your garden, quietly keeping the slug population in check for you.
If these salamanders are so common, how do they retain their ability to delight and amaze when pulled forth from under a log? Most animals this common elicit indifference (pigeons), irritation (mice), or outrage (woodchucks). How do salamanders maintain an aura of mystery despite such astonishing ubiquity? Unlike common animals that saunter around all day long in plain sight, red-backed salamanders stay under cover, and sometimes hide away underground, too. Revealing one gives a treasure-hunt thrill. They seem primordial, but an investigation into their life history shows unnerving alignments with our own. We tend to think wild animals are interchangeable automatons behaviorally. Read Wikipedia and it will tell you “this species does thus and so” as if there were no individual variation. But red-backed salamanders defy such pat ethography.
Salamanders live in a landscape of smells, defining their territories and demarcating the boundaries with scent cues. Some prefer to live singly, making contact with the other sex only briefly to mate, but others establish a pair bond and jointly defend a territory. When the male strays, coming home with scent molecules of another female clinging to his rubbery body, his mate, taking in the story of where he’s been, will hold her body high to look bigger, and then pick him up and slam him to the forest floor. Males will similarly punish females who return smelling of infidelity.
When these pair bonds form, it appears to be out of genuine choice. Any old male and female housed together do not build such a relationship out of simple proximity. It’s a decision some salamanders make upon meeting some particular other salamander. The mechanism for these choices is not, as they say, wholly elucidated. But then, what desires of any living thing ever are?