Working from home (as are most of us), Assistant Director Jenny Houghton has been working on Nature Notes to share in our weekly email newsletters (email us to sign up!).
I’ve been told that river otters live at the Arboretum, but I never saw evidence myself until recently. Taking advantage of sunny weather, my family left the confines of “stay at home” orders for a restorative Arboretum hike. After strolling past the wigwams, we turned onto the North Tuckahoe Valley Trail, stopping just before Nancy’s Meadow Cut to launch mossy fairy boats in the creek. That’s when I saw it.
Scattered, grayish mounds of crushed shell, fish scales, and bones may not seem particularly exciting. But animal enthusiasts like me become…well, enthusiastic about scat. The scat I found lying on the creek bank on Sunday had clearly had been left by Lontra canadensis, also known as the North American River Otter.
River otters are members of the Mustelidae family. Like other members of this family, they communicate and mark their territory via strong-smelling droppings. As I knelt on the ground for a closer look, it became obvious that Arboretum otters enjoy a typical diet of fish, crayfish, snails, and mussels. Later, at home, I checked to make sure I wasn’t confusing the droppings with those of another stream resident, the raccoon. But unlike the blunt edges of raccoon scat, this scat was tapered and clumpy rather than cohesive.
My children have short attention spans when it comes to scat, so we crossed the bridge leading into Tuckahoe State Park. To our left, we spied wide holes between the tree roots. Surely, these were entrances to otter dens. Otters do not dig their own dens, making use of natural openings or the burrows of other animals instead. In the spring, an entrance may lead to a nest of baby otters lined with moss, fur, and grass.
Known as pups, baby otters swim at just two months of age. Their bodies are perfectly adapted for a watery lifestyle, with tapered tails, webbed feet, eyes on top of their heads, and ears and noses that close when underwater. Unlike another well-known aquatic animal, the beaver, otters move easily both on land and in water. In fact, otters can travel distances of up to 26 miles a day!
Which leads me to the question of why we don’t see roaming bands of otters at the Arboretum. As it turns out, river otters are nocturnal throughout the year except during winter, when they are most active at dusk (diurnal). Anyone lucky enough to see a river otter may also hear it: river otters make a variety of sounds, including purrs, growls, hisses, chirps, whistles, and chuckles.
The presence of river otters at the Arboretum is a good sign. Otters have a low tolerance for environmental pollution and are unlikely to be found in degraded habitats. The area where I found the otter scat is not far from where my summer campers wade in warmer months. When camps resume, I’ll think of the otters as I watch my campers splash and play within sight of their creekside home.