When I moved from Washington, D.C., to Martha’s Vineyard in 1985 — just for a year, mind you — I expected some culture shock. D.C. is a big city. In the mid-1980s, more than three-quarters of the population was black. I lived and worked in the women’s community and had infrequent dealings with men. I got around by bike and foot and public transportation; I didn’t own a car.

Sure enough, there were differences. To my newly arrived eye, nearly all the women on Martha’s Vineyard looked like dykes: they wore jeans, flannel shirts, and sensible shoes, just like me. My jaw dropped whenever someone asked if I was married. You don’t get questions like that when you work at a feminist bookstore. When I said, “No, I’m a lesbian,” then the questioner’s jaw would drop because in the mid to late 1980s on Martha’s Vineyard no one ever said “lesbian” in public.

The Bourne Bridge. We live on one side. They live on the other.

But the longer I was here, the more similarities I noticed. Vineyarders, like the women’s communitarians, liked to emphasize how different we were from everybody else. Run into another Vineyarder, say, at the Burger King in Falmouth and it was like greeting long-lost kin, even if you didn’t especially like each other. Ditto when one lesbian feminist encountered another at a suburban mall or a chamber music concert: “We are everywhere!” we’d chortle, feeling like comrade spies behind enemy lines.

Vineyarders and lesbians also shared a penchant for serious hair-splitting on the matter of who belonged and who didn’t, and what degree of belonging one was entitled to claim. On the Vineyard it was a matter of how long you’d been here, whether you’d grown up here and/or been born here, and how many generations of your family could say likewise. Among lesbians, it was when you’d come out and whether you’d ever slept with a man.

Insularity, I concluded, was not peculiar to islands.

This past weekend, Trav and I went off-island to compete in a Rally Obedience trial in Westford, Mass. Westford is on the northern arc of 495, not far from New Hampshire and almost a two-hour drive from Woods Hole. Vineyard people like to talk about how strange and even scary things can be off-island, so I was pleased to find that I can still cruise at 70 mph and merge into high-speed traffic on the interstate. For years I was intimidated by self-serve gas stations — we don’t have those on Martha’s Vineyard — but no longer. Did I stick out in any way because I’m a year-round Vineyarder?

Not that I noticed. My credit card was accepted by the Motel 6 credit-card swiper. I made myself understood to the desk clerk; she made herself understood to me. I managed to make the card key open my room door. Hitting the Wendy’s across the road for a spicy chicken fillet combo two nights in a row was a special treat, but I didn’t tell the cashier that.

Susanna in sensible clothes; Travvy dressed for success. Rally trial, Littleton, Mass., October 2011.

At the trial, there was nothing distinctive about my clothes, my shoes, my size, my hair. We didn’t all look alike, but I was firmly in the ballpark. Dog people, like Vineyard people, tend to dress practical. They dress more country than city. This was true of many urban women’s communitarians in the 1970s and ’80s. Nearly all my life I’ve gravitated to places where I can dress in barn clothes, which is to say jeans, sturdy shoes or boots, flannel shirts in season.

True, I was almost certainly the only one watching the clock late Sunday afternoon and hoping that my last class, the last class of the day, would be over by 6 p.m. so I could make the last boat, the 9:45, without having to break any land-speed records. It was, and I did; in fact, I made it onto the 8:30 even though I stopped to gas up in Falmouth. Gas costs at least 60 cents more per gallon on this side of the water, so I feel like I’m putting one over on the universe when I can fill a nearly empty tank on the other side.

Travvy with the second leg on his Rally Level 3 title.

Come to think of it, Rally-O is something of an island within the larger world of dog sports, within the still larger world of dogs. I attended my first Rally trial, and my first dog show, a scant three years ago. I’m a novice, but I’ve picked up enough of the lingo to understand what people are talking about and even to make myself understood. “After three NQs, we finally got the second leg on our RL3 title”: that would make perfect sense to anyone at last weekend’s trial. People in other dog sports might not know that “RL3” means “Rally Level 3” but they’d know that an NQ is a non-qualifying run and that a leg is one step toward a title. (Three legs generally earn a title, which seems a little odd given that dogs have four legs and humans two; is three a compromise?) But to non-dog people that sentence would be incomprehensible. Four years ago I wouldn’t have understood it either.

Few of us, it seems, live on a single island. Rather we live on archipelagoes, paddling back and forth between islands. Most of us probably live on several islands at once.