There's no small comfort to be had as a hiker knowing you are at the top of the food chain.

Walking the towpath of the C&O Canal, which stretches 185 miles from Cumberland to Georgetown, I was treated with respect by the animal kingdom. Frogs fell back in terror; turtles clamped shut; wood ducks took wing. Panicked groundhogs scrambled into rocky dens. The sense of power was pleasant. Even house cats bolted from my path.

Then I met up with an extraordinary deer.

It happened at dusk at a camp called Leopards Mill between the towpath and the Potomac, 129 miles from Washington. There the river is so narrow that you can converse across it, and I am afraid a few people on the West Virginia shore were treated to the ludicrous spectacle of a deer cornering a human being atop a picnic table. May they be struck dumb.

Free of my backpack after a long day on the trail, I was hobbling about setting up camp for another night, when, in a thicket 20 yards away, I spotted a deer.

I'd seen deer before--four that afternoon, in fact, picking their way down a steep hill with exact and dainty steps--but never so close. I grabbed my camera, hoping to take some pictures in the waning light.

Minutes passed as I edged closer, taking a step, freezing, then taking another step, playing an interspecies game of Mother May I. The deer had no antlers--doe or a buck, I couldn't say. Its ears twisted about, listening in my direction. It seemed like a sweet, gentle deer.

Perhaps it knew Bambi.

Oh I hoped I wouldn't spook it.

Then it attacked.

Or something: The deer started out of the woods, toward me. I held my ground. I tried to project my place in the food chain. I tried to remember recipes for venison. Surely the creature would whirl and flee. Yet the devil marched closer, to 30 feet. Then it rushed me. I turned tail and fled.

Let me put abject cowardice into perspective. Stapled to trees at every campsite along the towpath were posters warning of a rabies epidemic in Allegheny County and parts of Washington County. On each were sketches of bats, raccoons and skunks with red Xs slashed across them, and the words: "Direct contact with these and other wildlife should be avoided. Any wild animals appearing friendly and unafraid of humans must be regarded as rabid."

I darted around a pile of firewood, fetched up my hiking stick, jumped up on a picnic table, and envisioning Bambi's Xed out face on the next edition of the rabies bulletin, prepared for my last stand.

The deer came to within the length of my stick. "You're a herbivore," I shouted, banging the stick on the table. (Addressing animals is one of the privileges of people who hike long distances alone.) "Get out of here! Amscray!"

With each rap of the stick, the animal quivered, but would not retreat. Not for any alarm I raised, it finally ambled over to a flat grassy patch where I had planned to pitch my tent, squatted and released a yellow stream. My humiliation seemed complete.

The deer sniffed around the trash can at the campsite, which contained two empty milk jugs, a pair of charred sneakers and a spent can of Yard Guard. It wandered off a bit. Feeling brave, I ventured off the picnic table and rolled a few pieces of firewood at its spindly legs. It looked annoyed, but essentially unperturbed.

I spent the next 20 minutes rolling logs and waving my arms, trying not so much to shoo the deer from my camp as to reestablish my authority. By dark, the bonfires were blazing on the West Virginia shore, convivial voices stole across the water, and I was still looking for a dry place to stake my tent.

In subsequent days, as I wound my way along the towpath, the only other creatures I feared were snakes. Maryland claims 27 species of snakes, but just two, the timber rattlesnake and the copperhead, are poisonous.

Historian Thomas Hahn's book on canal boatmen says that the mules that towed the barges could divine poisonous snakes and would drop their ears and refuse to budge until the snakes had been removed from the towpath.

For the benefit of those who can't afford to travel with a mule, the state of Maryland at Little Orleans, 141 miles up river, has posted a guide to telling snakes with venom from snakes that do without it. The difference is important because the towpath near Sharpsburg traverses four miles through an area researchers have dubbed the "Copperhead Capital of Maryland."

According to the state herpetologists, one way to know for sure is to examine a snake's "anal plate." Nonpoisonous snakes have double plates, poisonous snakes have single plates.

All well and good. Except what hiker, actually coming upon a snake, will have the presence of mind to examine the anal plate, much less figure out where it is exactly and what, exactly, is its function? Furthermore--and I passed many indignant miles preoccupied with these questions--what self-respecting snake is going to lie still for a physical exam from any fool who happens along?

As it turned out, I did meet with a snake, near mile 107. It was at the precise moment that I was not watching the trail but was absorbed in a magnificent view of the river. Something halted my legs in mid-stride. Sprawled on the path was a thick, shiny, black-colored snake, like a ropy piece of licorice four feet long, its head rising from its casually coiled body.

I tried rolling a piece of firewood at it, having had some success with rolling firewood at deer. The reptile would not yield. After a minute, I planted my stick, and vaulted hastily past. It was probably a nonpoisonous black rat snake, a common resident of towpath environs.

But I did not have it in me to check the plate.