By David Ryan, forester and project manager
While working along Ellsworth Creek not too long ago, I saw something splashing around upstream. Since it was not the season for a salmon run, that ruled out one possibility for the source of the ruckus. As I approached, a very distinct caterwauling became apparent.
At this point, I realized that I had come upon an indiscreet couple of North American river otters engaged in the business of life. The male was gripping onto the female with both claws and teeth, sometimes drawing blood — to human sensibilities the act seems rather unpleasant and more of a fight to the death than procreation.
Although, in another sense, it may be considered a fight for life:
Here's a neat collection of otter tales starting on page 265 of the North American River Otter: Husbandry Notebook.
River otters (Lontra canadensis) are complex, semi-aquatic mammals in the Mustelid family and possess a remarkable physiology and history. Although they are listed by the International Union for Conservation of Nature as stable and their national and global status is considered secure, they have been extirpated from many states in the Southwest and Midwest regions of the country.
River otter are listed in Appendix 2 of CITES, which means they are not currently threatened with extinction, but may become so unless trade is tightly controlled ‚ therefore, they can be hunted or trapped, but are subject to international restrictions and state quotas. They are trapped or hunted for their valuable pelts. In the 1970s, U.S. harvest consisted of 11,000 to 19,000 otters per year. Currently, 27 states have trapping seasons and four states have hunting seasons.
Despite hunting and trapping, the predominant reason for the regional extirpation of river otters is loss of habitat through development or environmental pollution. Climate change will likely negatively impact river otter populations in various regions.
From their vibrissae (whiskers), to their lungs, to their webbed feet, river otters have a dizzying and fascinating array of physiologic adaptations. One of the most interesting traits, and pertinent to the activity I witnessed, is that of embryonic diapause, or delayed implantation. Although true gestation lasts only a couple of months, embryonic diapause means that the embryo does not immediately implant in the uterus after fertilization, and it remains in a suspended state with little or no development for up to 10 or 12 months.
After almost a year, the embryo implants in the uterus and true gestation begins. Following true gestation, a litter of one to six pups are born. Theories as to why up to 100 mammals experience delayed implantation focus on protecting the mother or newborns. The mother may be awaiting more favorable environmental conditions or better physical constitution before undergoing childbirth.
Otters are often characterized as playful and expressive. They are the subject of numerous tales from indigenous peoples around the world. And they have quickly been elevated to a top-tier position in my personal list of favorite animals.
After several minutes of frenzied splashing, thrashing, and caterwauling, the amorous couple settled down and finally noticed me, at which point they swam backwards into their lodge, the male never letting go of the female and neither one taking their eyes off the peeping Tom caught looking in to their home. I walked away with the special qualities of Ellsworth yet again burned into my psyche.