“It is the bright day that brings forth the adder,” Brutus warned in Julius Caesar, “and that craves wary walking.” As I crossed the white dome of Big Moor, snakes were the last creatures on my mind. That morning’s blue skies had given way to dark, scudding clouds and a keen wind. Twelve hundred feet up, it felt too cold for snakes. I sank my chin into my jacket and walked less warily and more briskly.

The moor, rich with curlew and lark, is split by Bar Brook, dammed in the past but no longer; it descends to enter a smaller reservoir, sheltered with birch and willow. Here on the ground were sheets, randomly placed, of corrugated iron. This looks like building waste, but the tin was in fact placed deliberately 20 years ago to attract adders for a census. The warm air building up underneath was thought to be irresistible, herpetologically speaking.

Eye to eye with an adder Read more

Over the years, 10 or more, I’ve often stopped to peer hopefully under these sheets of metal, and not once have I seen a snake. Head down, I ignored them, marching past only to stop abruptly a little further on. From the corner of my eye I glimpsed the unmistakeable geometric pattern of a half-concealed adder, perched on top of a bank of bracken.

As I crept up, the glimpse resolved itself into a knot of plump, scaly flesh, two adders wound around each other, still surfing on the morning’s sunshine that had so recently faded. Unusually for snakes, the gender of adders can be sorted by colour; and these were males: their lustrous olive flanks in strong contrast to the fresh and well defined black chevrons down their backs. They had most probably just shed their skin in anticipation of mating.

Mesmerised, I briefly lost balance and stepped too heavily. Adders lack ears to hear, but they are highly attuned to vibration, which they sense through their lower jaws. Two elegant heads shot out, two forked tongues flickered briefly, and then, one after the other, they slipped slowly back into their burrows.

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