- Mary K. Hanson
- Posted On
Tuleyome Tales: It’s time for river otters
NORTHERN CALIFORNIA – We are right at the beginning of the breeding season for North American river otters (Lontra canadensis), so you will probably be seeing a lot of them in and around local rivers, streams, wetland areas, ponds and lakes throughout the Berryessa Snow Mountain National Monument region.
Related to weasels, otters are both “endemic” to North America and “crepuscular.” This means they’re found here in North America and nowhere else in the world, and that they are most active at dusk and at dawn.
During the winter months, though, you should be able to see otters swimming, fishing, and searching for mates during the daytime hours.
By the way, that “play” activity you see them doing – romping, wrestling, chasing and rolling over each other – is actually learning behavior.
Through their games, otters learn how to survive, how to fight and hunt, and how to, well … be otters.
Although they may, at first glance, seem somewhat gangly on land, they can actually run at speeds of up to 29 miles per hour – and slide on their bellies even faster. In the water, they tend to swim at speeds around 8 or 9 miles per hour.
When fishing or wrestling, otters can stay underwater for about eight minutes, and their ears and nostrils clamp shut to keep the water out.
Those long whiskers you see on the otter’s face are called “vibrissae” and help the otter to feel what’s around it in murky water.
The otter’s feet are also highly sensitive to touch, and it has heightened senses of smell and hearing.
Although a lot of otter communication is done through scent-marking, they can also vocalize with a wide variety of sounds: growling, barking, whistling, chuckling, purring and grunting.
Their “alarm call” is actually like a super-loud sneeze: the otter will force air out through its nostrils with a kind of concussive force.
Most of the groups of otters you see during the fall and winter months consist of a mother otter, her children (“pups”) and helpers (other females and pups not related to the main female in the group).
A group of otters, by the way, is called a “bevy” or a “raft” (when they’re in the water).
During this time of the year, the males will den separately from the females in loose-knit bachelor groups when they’re not seeking lady-friends.
Otters are not territorial and don’t mind sharing space with other otters even during the breeding season.
River otters breed between December and April, and the mama otter can have up to six pups in a litter. Pups are born fully furred, but can’t see or hear until they are about a month old.
Unlike European otters, female North American otters can actually delay the implantation of fertilized eggs for up to eight months.
So although her pregnancy itself will last only about two months, it could be 10 months to a year between the time she was breed and the time her pups arrive.
Because of this, it’s difficult to tell which female otters are pregnant and which are not until right before they’re ready to give birth.
Mother otters need a place to stay where they can rest and have their babies, but they are loathe to building anything for themselves and often take over the abandoned beaver dens or burrows of other animals.
If there’s no vacancy anywhere, otters will use whatever else is available such as hollow logs. Once the otters establish themselves, their home is referred to as a “holt.” The holt usually has several entrances, including at least one that leads directly to a water source.
Otters are highly susceptible to water pollution and will leave an area where the water has been tainted, so having active otters in our area is an indicator that we have healthy aquatic habitats in our region for them to use.
Be mindful, then, that when you flush oil, pesticides and other toxins down your driveway into the gutter, you might be contaminating the very water systems on which these beautiful creatures rely.
If you’re lucky enough to see some otters in the wild this season, please share your photos on Tuleyome’s Facebook page.
“Tuleyome Tales” is a monthly publication of Tuleyome, a 501(c)(3) nonprofit conservation organization based in Woodland, Ca. Mary K. Hanson is a Certified California Naturalist and author of “The Chubby Woman’s Walkabout” blog. For more information about Tuleyome, visit www.tuleyome.org .