The zoo’s American Trail exhibit presents new habitats for the animals.

At the Smithsonian’s National Zoo, squawks, barks and howls have finally replaced beeping trucks and blaring jackhammers. After five years of planning and renovation, the zoo’s new American Trail exhibit opened to the public last weekend. Most of the greenery surrounding the winding, sloping trail is meant to evoke the Pacific Northwest, with such plants as white birch, red maples, ferns and holly. The true stars of the new area, of course, are the animals — many of whom lived here previously, albeit in less-plush surroundings. Here are some of the trail’s must-visit residents.

Sophie, California Sea Lion

Sophie, a 14-month-old California sea lion, is new to the National Zoo.

(Zalophus californianus)

Meet one of the National Zoo’s newest darlings: 14-month-old Sophie, one of four female sea lions who live in the American Trail’s largest pool enclosure area along with a gray seal (and, starting this fall, three more seals). The daughter of sea lion Calli, 7, who’s also in the exhibit, Sophie already seems interested in others — even humans. “She has that pup’s curiosity,” says animal keeper Christina Castiglione, “and she does seem to interact with viewers” at the two shaded underwater viewing areas. In the sea lions’ daily demos, Sophie and Co. will display some of their species’ typical behaviors, including vocalizing, twirling in circles on rocks and in the water, and reaching up to touch objects with their noses. Keep an eye on Sophie’s development over the next few years, Castiglione says. “She’s very inquisitive, very excited to learn new things, and she is at the beginning of her training. You’re going to be able to see her grow.” And not just skill-wise: The pup, who now weighs under 100 pounds, is expected to reach the weight of a typical female California sea lion — 250 to 350 pounds — by the age of 5.

Niko and Konrad, North American River Otters

We couldn’t get definitive confirmation of whether this is Niko or Konrad. We do know he’s cute.

(Lontra canadensis)

Brother otters Niko and Konrad, age 13, are among the zoo’s old guard. Residents since 1999, they’re already used to their lush, green habitat — which was significantly expanded with new outdoor and indoor space and a wider range of viewing angles for visitors. But creatures of habit they are not: “They’re very smart, they learn very quickly,” animal keeper Malia Somerville says. “But they do have a short attention span, much like small children. You get kind of a short window, and then they’re off.” Expect to see these guys climb tree branches, forage for food and swim and dive in their pool (be sure to check out the underwater viewing area below their enclosure).

Crystal, Gray Wolf

Despite her species’ name, gray wolf Crystal has an entirely white coat.

(Canis lupus)

Crystal is one of two 8-year-old female gray wolves living along the American Trail. The wolves are newcomers to the National Zoo (the zoo previously exhibited Mexican wolves, which are a subspecies of the gray wolf). With her dusty white coat, Crystal would blend perfectly into the Arctic tundra. Coby, the other half of Crystal’s “pack” (the two, though not siblings, were raised together with Coby’s litter-mates), has salt-and-pepper gray fur. The wolves were raised at Canada’s Calgary Zoo, but animal keeper Rebecca Miller says they’ve settled into their spacious new Washington digs — which include dens made with timber repurposed from around the zoo — very nicely. Well, except for one thing: “Sometimes they’ll howl if they hear a siren going off in the background,” Miller says.

National Zoo, 3001 Connecticut Ave. NW; daily, free; 202-633-4800. (Woodley Park)