Rio came to Shedd from the Little Rock (Arkansas) Zoo in 1992, when she was 6 months old. So she’s otterly at home here. River otters are crepuscular, which means they are most active at dawn and dusk, so the first place to look for Rio is in her den on the left side of her habitat, where she likes to catnap. For an older river otter, however, Rio is still plenty energetic, and she makes regular circuits of her roomy pools, delighting guests.
Twice a day, she has a 45-minute training session with a member of the river otter team, which includes staffers from both the Fishes and Marine Mammals Departments. During these sessions, Rio comes to a specific shape, a red circle, just like the belugas and dolphins do. She’ll follow a hand-held target or swim from one point in her habitat to another. She also does “ups”—the natural behavior of standing on her back legs—on a cue. Her trainers have another way to get her to do these vertical stretches, by hiding treats above eye level in her habitat.
Rio also has lots of enrichment toys—a closetful, in fact—including felt car-wash strips, Kong toys and other items designed for dogs and zoo animals that are sturdy enough to pass the “otter-proof” test. One toy is a large blue storage bin. Senior aquarist Alice Bereman, who is co-leader of the river otter team, recalls, “I don’t know what the process was, or whether it was by accident, but Rio was pushing the upside-down bin around the exhibit with her head when she came to a stop beneath a ledge where we’d hidden a chunk of fish.” Sometimes during morning training sessions, treats are hidden around the exhibit for Rio to hunt. With her keen sense of smell, she finds them all. This time, however, she amused Alice by hopping onto the bin, “like it was step ladder, to get the treat. She used the bin like a tool.”
The training sessions give the otter mental and physical exercise as well as practice in behaviors for routine exams, such as “open mouth,” to check her teeth, and “paw tactile,” to allow team members to touch and examine her paws and pads.
Once in a while, Rio’s focus drifts and she plunges back into the water for a zoom around the pools. River otters can stay underwater for up to four minutes. Like sea otters, they have thick waterproof fur that traps body-heated air to keep them insulated in cold water.
And, like sea otters, their populations were decimated by fur trappers in the late 19th and early 20th centuries. Widespread habitat loss, as wetlands were drained and converted to farmland, and heavily polluted rivers nearly finished off this species throughout North America. Once abundant in the many river systems that crisscross Illinois, river otters hung on in only two small populations by the time they were added to the state’s endangered species list in 1989.
They owe their recovery in large part to the federal Clean Water Act and its strict water-quality regulations, which made vast stretches of our state’s waterways livable for wildlife again. With adequate restored otter habitat, in 1994, the Illinois Department of Natural Resources initiated a reintroduction program in the Kaskaskia, Wabash and Illinois Rivers, supported by Illinois taxpayers through the Wildlife Preservation Fund—the tax checkoff on your IL1040.
Some of the reintroduced otters came from Louisiana, purchased with the wildlife funds; the rest of the animals needed were obtained through a creative trade agreement. Illinois lacked river otters but had abundant wild turkeys. Neighboring Kentucky had plenty of otters, but needed wild turkeys for a reintroduction program. A deal was struck.
Biologists were amazed by the otters’ swift recovery as well as by their ability to adapt to modern landscapes. In just 10 years after the first reintroductions, river otters had rebounded so successfully that the species was removed from the Illinois endangered list.
Today, more than 10,000 river otters—up from fewer than 100 in the 1980s—call Illinois home, and you’ll find them in waterways in all 102 counties, including Cook. (The 2008 surprise Chicago sighting was in Lake Michigan, but river otters have been spotted in nearby suburban waterways for several years.)
And that’s good news for us and for our local environment. River otters are premium indicator species: You’ll only find them where the water quality is good and the fishes and other aquatic life they prey on are diverse and plentiful.
So on World Rivers Day, we can celebrate Rio and the return of river otters. But we can do more: We can all contribute to the recovery of other aquatic species by supporting programs that are already in place to protect local waterways, including the federal Clean Water Act and Illinois’ own Wildlife Preservation Fund. And a great way to learn firsthand about our local waters is to take part in one of Shedd’s outdoor programs for kids, families and adults. You just might see a flash of brown fur before it disappears into expanding rings of river water.
—Posted by Karen Furnweger, web editor