The arrival of two new roommates has made life in the otter exhibit at the High Desert Museum uncommonly lively for Thomas, the exhibit’s lone resident since early 2007.

Otters Rogue and Sandy arrived last week from Ohio, where they’d been part of a traveling wildlife exhibit, according to John Goodell, the museum’s curator of natural history. The two 3-year-old males have made themselves at home in the exhibit, snuggling up in the warm den inside and periodically venturing out for a swim in the pond. Thomas, now 16, fairly old for an otter, has been pushed to the margins — on Tuesday, the museum’s elder otter spent much of the day under a thicket of branches and pine needles he’d built as far away from the new residents as possible.

Museum vice president of programs Dana Whitelaw said it’s expected it will take a month or two for tensions to thaw in the otter exhibit. Otters can sometimes be solitary creatures, but at times, she’s seen groups of up to nine otters spending time together in the wild. In captivity, all-male groups have generally been found to get along well, she said.

Janeanne Upp, president of the museum, said the otter exhibit is the oldest still-operating attraction at the 31-year-old museum. Shortly after the death of Mokey, the last otter to share the exhibit with Thomas, museum officials began the search for a replacement, Upp said.

Even for a museum dedicated to natural history and native wildlife, getting your hands on an otter is no small task. In order to deter the trade in animals captured in the wild, Upp said, the U.S. Department of Agriculture and the Oregon Department of Fish and Wildlife require permits for anyone seeking to own an otter. Four years passed between the museum’s initial inquiries with both agencies and their getting the OK to take in Rogue and Sandy.

Since their arrival on the evening of Feb. 27, Rogue and Sandy — named after the Oregon rivers — have largely been given the run of the otter exhibit, while Thomas has often been kept inside. To protect them from cougars, bobcats and similar predators, which could theoretically jump the compound wall, all three otters bunk down at night in indoor pens where they can see and smell each other, Goodell said, hopefully accelerating the socialization process.

Thomas has always been an affectionate otter, Goodell said, often circling around his handlers’ ankles like a house cat. Whether he needs the additional socialization that comes with his two neighbors is unclear, Goodell said, but visitors to the otter exhibit in recent years have often made note of his isolation,

“Even my mom was like, ‘John, he seems very lonely,’” Goodell said.

Museum staff give an “otter talk” at 2 p.m. daily at the otter exhibit.