Wedged between gnarled branches of scrub oak, Fyodor, 11, scoured the coppice for any sign of treasure. For almost an hour, he and his brother, Alex, 12, had trekked through the dunes, following directions on a hand-held global positioning system device. Without complaint, they had conquered daunting sandy crests studded with bluish blades of sharp beach grass and skidded down into valleys ablaze with scarlet and amber foliage of sassafras and beech - all in pursuit of mysterious riches left at the Cape Cod National Seashore.
Parents, take note: Tracking down hidden booty with the help of an electronic device is a great way to get kids to explore New England's natural beauty on a long hike. Behold geocaching, an outdoor treasure hunt in which players program geographic coordinates into portable GPS receivers to find caches left by other players, and, in turn, leave something for future seekers.
Since the game's inception several years ago, the worldwide community of players has grown beyond its original base of nature lovers and gadget geeks: Plymouth Community Intermediate School, for example, offers geocaching as an after-school club. Patty Kogut, a geocacher from Middleborough, said the activity got her two preadolescent children "walking and learning about the outside, and trails, and the GPS." And handing GPS devices to your children takes care of the exasperating refrain, "Are we there yet?," since the gadgets tell users how far they are from their destination.
As an added bonus during an economic crisis, geocaching can be done at no cost at all -providing you have a GPS receiver - since it is probable that someone has hidden a cache not far from where you live, maybe even within walking distance. I hear there is a cache in the 18th-century cemetery a 20-minute hike from my backyard.
The contents of caches vary widely, but most are eclectic collections of treats tucked into a container: bags of marbles, packets of coffee and tea, magnets, $5 off coupons for a nearby whale watch. They are typically slightly camouflaged to conceal them from "muggles," a term for the uninitiated borrowed from novelist J.K. Rowling's Harry Potter series. (The problem with muggles is that they usually don't replace caches they take, a violation of the rules of the game.)
Some caches consist of just one item, like the painted rock Ipswich artist Chris Sammartano planted in a cave just outside the Valley of Fire in Nevada several years ago. Unfortunately, Sammartano forgot to list the coordinates for the cache on the website right away, and, with time, the coordinates escaped his memory, "so it's just sitting there, waiting for someone to find it," he said.
Often the most valuable prizes are the treasures that seekers find along the route. The point of our family's inaugural geocaching hike this fall was to have our picture taken by a Web camera hidden in the window of Yellow Umbrella Books on Main Street in Chatham. The camera takes a picture once an hour between 10:30 a.m. and 3:30 p.m. and downloads it to a website.
We arrived early and took a stroll through the quaint town, making a purchase at Blue Water Fish Rubbings, which sells clothes and bags individually etched with imprints of sea fauna by local artist Jenny Bovey. At Yellow Umbrella Books, which sells new and used books, Alex and Fyodor browsed through the children's section. The adults also explored, finding such gems as the 1931 recipe book "The Silent Hostess Treasure Book." We ended up purchasing a cookbook from Carol McManus, a local restaurateur and author who was signing her books outside - unbeknownst to her, right in front of the camera.
Eric Linder, the bookstore owner, is not a geocacher. But he says he benefits from hosting the webcam because many geocachers become his customers. "It does get people outside and gets them going places they wouldn't otherwise go," Linder said.
You could say this about our second geocaching destination, Wood End Light, a gleaming white lighthouse that graces the southern curve of Provincetown's Long Point. The 3-mile round-trip hike takes geocachers on a precarious walk across the 1911 breakwater that spans tidal marshes in Provincetown Harbor. Sections of the granite jetty become submerged at high tide; even at low tide, some slabs of stone remain dangerously slippery.
Hikers are rewarded with stunning views: the black and white plumage of northern eiders that glide on top of translucent green water, and cormorants speeding just beneath the surface in pursuit of fish. A lucky bird-watcher might spy some slouching, speckled bitterns and pied-billed grebes that hide in the tall stalks of cord grass, which in fall turns the amber color of ripe wheat. The walk's climax is a stroll along an almost always deserted beach beneath the lighthouse.
Wood End, like the Chatham webcam, holds no physical prize. If you want to prove that you made the trek, e-mail the person who set up the cache and goes by the nickname Ambrosia with the number of windows on the lighthouse (we counted them, but I'm not telling!).
By our third geocaching trip, the boys announced that they were ready to take on the oldest cache on Cape Cod, originally hidden in March 2001 on the Cape Cod National Seashore: a fragile forest growing on dunes formed over millennia out of pulverized granite gravel by winds, tides, and storms. Panting, sometimes crawling on all fours, but careful not to step on miniature green cones of sphagnum moss and the silver froth of lichens that help contain erosion, Fyodor and Alex arrived at a scrub oak copse. Alas, nothing there.
In the end, they weren't the ones who found the cache just one sand dune away. A group of eight families, including 10 children, had gotten there minutes earlier, led by veteran cacher Sammartano. ("I was like, there's cash? In the dunes? said Susan Love from Milton, the mother of two of the children and a geocaching neophyte.) The kids were going through their loot and handwritten logs of previous seekers when Fyodor and Alex arrived. In the noncompetitively fraternal spirit of geocachers, they invited the boys to partake in the plunder. Fyodor picked a dollar and a finger puppet, Alex a rare penny. The boys left a Jurassic Park computer game, a super ball, and a rubber crab, and returned the cache to its hiding spot under a . . . OK, no more hints.
We leafed through the log of other cachers' adventures. One joked he had to wander the dunes searching for so long he had to eat his partner to avoid starvation. Someone left a laminated card made to commemorate their recent geocaching cross-country road trip. We felt compelled to sign the log as well.
We wrote: "Read about it in The Boston Globe."
Anna Badkhen can be reached at firstname.lastname@example.org.