The Humble Muskrat: Is He Disappearing?

Muskrats are often an overlooked species in the Land Between region and are frequently seen as pests. However, muskrats are actually beneficial and have great cultural, ecological, and economic importance. 

Muskrats are semi-aquatic rodents that are active year-round and commonly found in most of North America in marshes, beaver ponds, streams, rivers, and lakes (Saunders, 1988). With small eyes and ears, and brown fur with long, glossy guard hairs, they are similar in appearance to the beaver but are much smaller and have a thinner, rounded tail. They build houses with mud and aquatic plants, or dig burrows in the banks of ponds, lakes, and streams. They mainly feed on roots, stems, the leaves of cattails, and other aquatic plants but will also eat herbaceous plants, the flesh of dead animals, insects, crayfish and freshwater mussels (Saunders, 1988). The muskrat’s large feet propel them through the water while their tail acts as a rudder. While they usually swim on the surface, they will dive underwater if disturbed or to reach the roots of aquatic plants, and can impressively remain submerged for up to 17 minutes, travelling up to 46 metres (Saunders, 1988). 

In the Anishinaabe creation story, the muskrat provides a necessary sacrifice and is a symbol of courage, kindness and humility. In a version retold by Anishinaabe storyteller Basil Johnston, the Earth has been flooded leaving only birds and water creatures to survive (MacGregor, 2013). Sky-Woman rests on the back of a great turtle and asks the water creatures to bring soil from the bottom of the water so she can use it to make new land. Several water animals, including the beaver, marten, and loon try to help but fail. The humble muskrat determinedly volunteers despite being smaller, weaker and ridiculed by the other animals. After much time had passed, the muskrat finally emerged from the water with a small ball of earth clutched in his paw. The muskrat used all of the energy and breath he could muster but had gone too long without air and died by the time he emerged. Muskrat humbly sacrificed his life so that Earth could begin anew, and all the animals shouted with joy. The turtle offered his back to bear the weight of the earth, and the tiny piece of earth grew and grew (MacGregor, 2013). 

Not only are muskrats culturally significant, but they are also economically significant, ranking as the top harvested wild furbearer in North America of the 20th century (Sadowski and Bowman, 2021). In the early 1900’s, millions of muskrats were trapped and sold across North America, and over the past 150 years the muskrat has contributed more than any other animal to the combined income of North America’s fur trappers (Sadowski and Bowman, 2021). Although harvest numbers are lower today, the muskrat is still a major source of income for fur trappers. Even when harvested in large quantities in the past, muskrats have been resilient to harvest and other population pressures, such as disease and predation, thanks to their demographic characteristics (Sadowski and Bowman, 2021). They typically have 2-3 litters per year with an average litter size of 6-7 kits and most are able to breed the same year they are born (Saunders, 1988). Muskrats also have flexible habitat requirements, and have an exceptional ability to survive up to the very limits of what could be considered habitable (Sadowski and Bowman, 2021). For example, they can survive droughts notably well, and when they have to, may eat any organic material they can find, and are remarkably efficient at digesting harsh food (Errington, 1939). Being such a prolific and adaptable species has allowed muskrats to be a steady source of income for fur harvesters, and food for many predators. 

Muskrats have significant ecological benefits as well, positively impacting wetland biodiversity and the habitats of multiple species, some of which are at risk. Similar to beavers, muskrats are also considered ecosystem engineers, altering their environment through their activities and creating niches that would not exist otherwise (Kua et al., 2020). Muskrat activity can influence invertebrate communities, mussel abundance, microbial activity, and nutrient cycling (Sadowski and Bowman, 2021). Their foraging, travel, and house building activities create several small openings in wetlands, which allows vegetation to grow and spread and therefore increases plant species richness and diversity (Kua et al., 2020). Since the presence of muskrats creates an equal amount of open water and vegetation within a wetland, a greater number of marsh birds and waterfowl have been found in these wetlands, as it best suits their needs. Marsh birds and waterfowl, such as the black tern and trumpeter swan, use muskrat houses as important loafing and nesting sites (Sadowski and Bowman, 2021). Many reptile species, including snakes and turtles, have been observed using muskrat houses, burrows, and cleared pathways for thermoregulation, nesting, cover, and ease of travel (Sadowski and Bowman, 2021). This is extremely valuable as many of these are species at risk. For example, the spotted turtle has been found in deep open water pools where muskrat grazing decreased the vegetation cover, likely serving as a refuge for the turtles through high temperatures and drought (Sadowski and Bowman, 2021). Finally, muskrats are an important and consistent food source for many predators in the Land Between, including red foxes, coyotes, raccoons, raptors, snapping turtles, and mink (Sadowski and Bowman, 2021). 

Although muskrats are very resilient to population pressures because of their quick reproduction and flexible habitat requirements, a recent study has revealed a long-term decline in muskrat populations. At the Point Pelee National Park marsh and the Matchedash Bay-Gray Marsh wetland, the authors of the study found that average muskrat house counts declined by 93% and 91% respectively between historic surveys 40-50 years ago and contemporary surveys over the past 7 years (Sadowski and Bowman, 2021). These study results support anecdotal evidence of muskrat decline and are consistent with reported trends in provincial harvest data. While the cause for this decline is unclear, it is less likely that it is a result of harvest, predation or disease, since they have historically been known to quickly recover from such threats. More likely causes for this decline are record high and extended low water levels brought on by weather extremes and climate variability over the past few decades, the loss of critical wetland habitat, and the change in overall quality of muskrat habitat (Sadowski and Bowman, 2021). At both study sites, a decrease in open water, plant and habitat diversity was found between 1959 and 2015, likely caused by invasive plant species such as Phragmites australis and the hybrid species of cattail (Typha X glauca) displacing the native broad-leaved cattail and other aquatic plant species (Sadowski and Bowman, 2021). The habitat changes caused by these invasive species negatively impacts the habitat quality for the muskrat. This decrease in muskrat populations is not only a direct concern for the loss of wetland ecosystem services they provide, but also an indication of marsh ecosystem degradation. Muskrat decline is a warning for the state of biodiversity in our wetlands (Sadowski and Bowman, 2021). To prevent further loss of the muskrat, more research, appreciation and understanding of the current state of the muskrat and our wetlands is needed. 

Despite being an often overlooked species, the muskrat has great ecological, cultural, and economic importance within the Land Between. The decline and potential loss of muskrats would have significant negative impacts. Muskrats promote greater diversity within our wetlands, providing ecological services to other wetland species and humans. They are highly valued by trappers and are an important part of our natural heritage, and in many Indigenous cultures are revered for the life-giving role they played in the creation of Earth. 

Written by Kirstin Colliss, Image by Tim Wilson

References 

Errington, P.L. (1939). Reaction of muskrat populations to drought. Ecology, 20(2), 168-186.

Kua, Z.X., Stella, J.C., & Farrell, J.M. (2020). Local disturbance by muskrat, an ecosystem engineer, enhances plant diversity in regionally-altered wetlands. Ecosphere, 11(10):e03256. 10.1002/ecs2.3256

Sadowski, C. & Bowman, J. (2021). Historical surveys reveal a long-term decline in muskrat populations. Ecology and Evolution, 11(12), 7557-7568. https://doi.org/10.1002/ece3.7588

MacGregor, D. (2013). Teachings from the Muskrat. Muskrat Magazine.com. http://muskratmagazine.com/teachings-from-the-muskrat/. Accessed August 2022. 

Saunders, D.A. (1988). Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.

The Creation Story – Turtle Island:

https://ied.sd61.bc.ca/wp-content/uploads/sites/112/2019/02/Ojibway-Anishinabe_Creation_Story.pdf