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Muskrat

The muskrat (Ondatra zibethicus) is a medium-sized semiaquatic rodent native to North America, belonging to the family Cricetidae and recognized as the sole extant species in its genus.^[1] Weighing 0.9–1.8 kg and measuring 26–36 cm in body length with an additional 20–28 cm tail, it features a stocky build, webbed hind feet for swimming, and a laterally compressed tail for propulsion, alongside dense fur that provides insulation and buoyancy.^[2] Adapted to wetland habitats such as marshes, ponds, and streams, muskrats construct dome-shaped lodges from aquatic vegetation and excavate bank burrows for shelter, exhibiting crepuscular or nocturnal activity year-round.^[3] Primarily herbivorous, they consume roots, stems, and leaves of plants like cattails and pondweeds, though they occasionally eat invertebrates or small vertebrates, influencing wetland vegetation dynamics through foraging and lodge-building that can enhance habitat diversity or cause erosion and infrastructure damage.^[4] Abundant across their range from northern Canada to Mexico, muskrats have been introduced to Europe and Asia where they often become invasive, and they hold economic significance as a furbearer, with pelts historically harvested for clothing, though populations remain stable and classified as Least Concern by the IUCN.^[5]

Taxonomy and nomenclature

Etymology

The English common name "muskrat" arose as a folk etymology from Algonquian languages of eastern North America, specifically adapting terms such as the Powhatan muscascus (meaning "it is red," in reference to the rodent's reddish-brown fur) or related Abenaki mòskwas, with the "musk" element likely influenced by the animal's strong odor from perianal scent glands and its rat-like body form.^[6]^[7] The binomial Ondatra zibethicus, established by Johann Christian Daniel von Schreber in 1788 (building on Linnaeus's earlier Castor zibethicus of 1766), incorporates indigenous and classical roots. The genus Ondatra stems from the Huron-Wyandot word ondatra or ondathra, the native term for the muskrat, transmitted into scientific usage via French explorers and naturalists in the 17th–18th centuries. The specific epithet zibethicus derives from Latin zibethus (civet musk or perfume from the civet cat), denoting the muskrat's musky glandular secretions used in territorial marking and communication.^[8]^[9]

Scientific classification

The muskrat, Ondatra zibethicus (Linnaeus, 1766), is a rodent classified in the domain Eukarya, kingdom Animalia, phylum Chordata, class Mammalia, order Rodentia, suborder Myomorpha, superfamily Muroidea, family Cricetidae, subfamily Arvicolinae, tribe Ondatrini, genus Ondatra (monotypic), and species O. zibethicus.^[10]^[11]^[12] This placement reflects its evolutionary affinities with voles and lemmings in the Arvicolinae, distinguished by aquatic adaptations from terrestrial ancestors in the Microtus-like lineage.^[13] The binomial name derives from Latinized Native American terms, with Ondatra from Algonquian roots and zibethicus referencing musky odor, originally described by Carl Linnaeus in Systema Naturae (12th edition, 1766).^[10]^[11]

Subspecies

The muskrat (Ondatra zibethicus) is classified into 16 subspecies, which exhibit variations in geographic distribution, population dynamics, behavioral habits, and habitat preferences across North America.^[3] These distinctions arise from adaptations to regional environmental conditions, such as climate and vegetation, though intergradation occurs in overlapping zones.^[3] The following table enumerates the subspecies and their primary distributions:

Subspecies	Distribution
O. z. zibethicus	Eastern United States and southeastern Canada
O. z. albus	Manitoba and adjacent central Canada
O. z. aquilonius	Labrador and adjacent Ungava and Quebec
O. z. bernardi	Colorado River areas of southeastern California, southern Nevada, western Arizona, and Mexico
O. z. cinnamominus	Great Plains
O. z. goldmani	Southwestern Utah, northwestern Arizona, and southeastern Nevada
O. z. macrodon	Mid-Atlantic Coast
O. z. mergens	Northern Nevada and parts of adjacent states
O. z. obscurus	Newfoundland
O. z. occipitalis	Coastal Oregon and Washington
O. z. osoyoosensis	Rocky Mountains and southwestern Canada
O. z. pallidus	Southcentral Arizona and west-central New Mexico
O. z. ripensis	Southwestern Texas and southeastern New Mexico
O. z. rivalicius	Southern Louisiana, Mississippi coast, western Alabama, and eastern Texas
O. z. spatulatus	Northwestern North America
O. z. zalophus	Southern Alaska

Southern subspecies, such as O. z. rivalicius and O. z. macrodon, tend to be smaller in body size with brighter pelage compared to northern forms like O. z. zibethicus. Taxonomic revisions have occasionally synonymized or debated certain designations, but the 16-subspecies framework remains standard in regional wildlife assessments.^[4]

Physical description

Morphology and size

The muskrat (Ondatra zibethicus) possesses a robust, compact body adapted for semiaquatic life, with adults typically measuring 20 to 35 cm in head-body length.^[2] The tail, which is vertically flattened, scaly, and sparsely haired, adds 20 to 28 cm, yielding a total length of 46 to 67 cm.^[13] ^[2] Adult weights range from 0.6 to 2 kg, with males averaging slightly heavier than females at approximately 923 g versus 839 g in Texas populations.^[14] ^[15] The body is covered in short, thick fur consisting of dense underfur and longer, coarser guard hairs, typically colored medium to dark brown, which provides insulation and waterproofing.^[2] The head is rounded with small eyes and ears positioned high on the skull, and the muzzle features prominent incisors suited for gnawing vegetation.^[16] Limbs are short, with small front feet and larger hind feet bearing partially webbed toes that aid in propulsion through water.^[17] Both sexes possess perineal musk glands, and males have a baculum.^[13] Size variations occur regionally and with age, but northern populations tend toward larger body sizes compared to southern ones, reflecting Bergmann's rule in ectotherms and endotherms adapted to colder climates.^[15] Juveniles reach adult dimensions within several months, though full weight may develop later in the first year.^[18]

Sensory and physiological adaptations

Muskrats possess limited visual acuity, with eyes positioned on the sides of the head for a wide but shallow field of view, supplemented by nictitating membranes that protect the cornea during submersion. Their senses of hearing and olfaction are also underdeveloped relative to terrestrial rodents, rendering them vulnerable to abrupt environmental shifts like temperature changes. Instead, tactile sensitivity via vibrissae likely aids in detecting underwater obstacles and prey, though quantitative data on whisker follicle innervation density remains sparse.^[11] Physiologically, muskrats exhibit a robust diving reflex triggered by trigeminal nerve stimulation from water contact with the nares, inducing apnea, pronounced bradycardia (heart rate dropping to 20-68 beats per minute from a resting 200), and selective peripheral vasoconstriction to prioritize oxygen delivery to vital organs. This response enables submergence durations of 12-17 minutes, with aerobic dive limits averaging 5-10 minutes depending on experience and season. Winter acclimatization boosts blood and muscle oxygen stores by up to 30%, extending aerobic capacity, while hemoglobin properties enhance O₂ unloading and CO₂ buffering under hypoxia.^[19]^[20]^[21]^[22] Anaerobic metabolism supports prolonged dives, evidenced by post-immersion lactic acid accumulation and elevated oxygen debt recovery, though mild immersion-induced hypothermia (core temperature drop of 1-2°C) has negligible impact on metabolic costs or dive performance. Thermoregulation involves regional heterothermia, where reduced blood flow cools the tail and limbs (to 5-10°C below core), minimizing conductive heat loss in cold water without compromising locomotion. Brown adipose tissue activates during sustained immersion at 3-10°C, generating heat via non-shivering thermogenesis to stabilize core temperature. Valved nostrils and lips that seal behind incisors permit underwater respiration retention and feeding, respectively.^[23]^[24]^[25]^[26]^[27]

Geographic range

Native distribution

The muskrat (Ondatra zibethicus) is native to North America, where its range extends from the Arctic treeline in northern Canada and Alaska southward across most of the continent to the Gulf Coast, the Rio Grande Valley, and the lower Colorado River in northern Mexico.^[12] ^[11] This distribution encompasses wetlands, marshes, ponds, lakes, and slow-moving rivers throughout Canada, the United States, and adjacent Mexican territories, though populations are sparse or absent in arid southwestern regions, parts of California, Florida, and Texas due to unsuitable dry habitats.^[28] ^[29] Within this native range, muskrats thrive in freshwater and brackish environments with abundant emergent vegetation such as cattails, supporting densities that vary regionally but peak in productive northern wetlands.^[30] Historical records indicate the species' presence predates European settlement, with fossil evidence confirming long-term occupancy in Pleistocene deposits across the continent.^[13]

Introduced ranges and invasiveness

The muskrat (Ondatra zibethicus) has been introduced to regions beyond its native North American distribution, mainly for fur production, with initial efforts in Europe dating to the early 20th century.^[13] Introductions included Finland in 1919 and Russia's Kola Peninsula in 1931, from which populations dispersed widely across northern, eastern, and central Europe.^[31] Secondary spread has established invasive ranges throughout much of Europe, as well as parts of Asia including Russia, Mongolia, China, and Japan.^[32] Limited introductions have also occurred in South America. In introduced areas, muskrats exhibit invasive characteristics, rapidly colonizing wetlands and acting as ecosystem engineers through burrowing and foraging that alter habitats.^[32] Their activities damage infrastructure by undermining dikes, embankments, railways, and dams, exacerbating flood risks in engineered landscapes such as those in the Netherlands and other low-lying European regions.^[33] Ecologically, they consume aquatic vegetation, potentially reducing habitat for native species and contributing to biodiversity shifts in invaded wetlands.^[34] Economic impacts include losses to agriculture and water management systems, prompting widespread control efforts.^[13] Management strategies focus on population reduction via trapping and eradication programs, particularly in the European Union where muskrats are regulated as invasive alien species.^[33] In countries like the Netherlands, annual trapping exceeds hundreds of thousands of individuals to mitigate damage to flood defenses.^[31] Despite these measures, complete eradication remains challenging due to the species' high reproductive rate and adaptability.^[35]

Ecology

Habitat preferences

Muskrats (Ondatra zibethicus) primarily occupy wetland habitats with permanent or semi-permanent standing or slow-moving water, including freshwater and brackish marshes, ponds, lakes, sloughs, streams, canals, and drainage ditches.^[36]^[37] These environments must support dense stands of emergent aquatic vegetation, particularly cattails (Typha spp.), bulrushes (Scirpus spp.), sedges, and grasses, which provide food, cover, and materials for lodge construction.^[38]^[39] Optimal water depths range from 0.5 to 2 meters to facilitate swimming, foraging, and escape from predators while allowing lodges or burrows to remain above typical flood levels.^[18]^[40] In regions with variable salinity, muskrats exhibit flexibility but often favor areas with a mix of brackish water and vegetation; for instance, a 50:50 ratio of brackish conditions to dense cover is considered ideal in coastal settings, where they preferentially select clay-rich soils for burrowing stability over sandy substrates.^[41]^[3] They avoid fast-flowing rivers and deep open water lacking vegetation, as these lack the structural complexity needed for shelter and thermoregulation.^[42] Habitat suitability is further enhanced by minimal disturbance and connectivity to adjacent uplands for occasional foraging, though muskrats rarely venture far from water edges.^[43]^[40]

Diet and foraging behavior

The muskrat (Ondatra zibethicus) maintains a primarily herbivorous diet centered on aquatic vegetation, with cattails (Typha spp.) serving as a staple due to their prevalence and nutritional value, including rhizomes and basal portions that provide digestible energy.^[40] ^[44] Other common plant foods include bulrushes (Scirpus spp.), sedges (Carex spp.), waterlilies (Nymphaea spp.), arrowhead (Sagittaria spp.), and wild rice (Zizania aquatica).^[40] In coastal marshes, such as those in Louisiana, Olney bulrush (Scirpus olneyi) can constitute up to 80% of consumption.^[40] Opportunistic intake of animal matter supplements the diet, particularly in resource-limited conditions; mussels may comprise up to 51% in certain populations like those in Kentucky's Green River, while crayfish, snails, small fish, and turtles are also consumed, with direct observations of crayfish predation occurring via repeated underwater dives every few minutes.^[45] Animal foods generally represent a minor portion overall, varying by habitat and season, such as higher proportions in northern lakes during spring and summer.^[45] Foraging occurs mainly in shallow waters near lodges, limited to 5-10 meters in some habitats, where muskrats use powerful incisors to sever stems and roots, often caching or transporting food to feeding platforms constructed from matted vegetation.^[40] Behavior is shaped by predator avoidance, with foraging bouts declining with distance from dens and open water escape routes like sluiceways, prioritizing efficiency and safety over exhaustive resource exploitation.^[44] Activity peaks at twilight but extends diurnally and nocturnally, with bimodal patterns in summer featuring major bouts from sunset to sunrise; muskrats consume roughly one-third of their body weight daily to meet high metabolic demands.^[11] In winter, reliance shifts to stored rhizomes accessed under ice, without significant food hoarding.^[40]

Population dynamics and cycles

Muskrat (Ondatra zibethicus) populations exhibit marked fluctuations driven by high fecundity, with females capable of producing multiple litters annually, leading to rapid increases under favorable conditions, followed by declines due to density-dependent factors such as resource depletion and increased mortality.^[2] These dynamics often manifest as cyclic patterns, with periodicity varying geographically; in Canadian regions, cycles typically span 8–9 years, though estimates range from 3 to 13 years based on harvest and survey data analyzed via spectral methods.^[46] Shorter 3–4-year cycles occur in some northern or ecozone-specific populations, potentially linked to synchronization with small mammal fluctuations or local habitat variability.^[47] Cycle amplitudes and reliability differ by location and methodology; for instance, Lomb–Scargle periodogram analyses of harvest records in parts of the United States indicate weaker, less consistent cycles compared to traditional expectations, urging caution in interpreting short-term data as definitive evidence of strong periodicity.^[46] Predation by American mink (Neovison vison), whose populations may inversely cycle with muskrats, contributes to these patterns, as does forage availability—overexploitation of emergent vegetation like cattails leads to lodge abandonment and emigration during peaks.^[46] Disease outbreaks, such as tularemia, and harsh winters exacerbate crashes, with survival rates dropping below 20% in overpopulated marshes.^[3] Recent trends show long-term declines in many North American populations, with harvest numbers falling over 90% in some areas since the late 1960s, potentially reflecting low phases in extended cycles or chronic habitat degradation from invasive plants like Typha spp. and wetland drying.^[48] ^[49] In stable but low-density systems, such as Prince Edward Island marshes, populations persist without clear cycling, suggesting resilience thresholds influenced by interspersion of wetland patches rather than absolute size.^[50] Monitoring via house counts or camera traps reveals that while irruptive booms remain possible in recovering habitats, overall densities have stabilized at lower levels, impacting fur harvests that once relied on peak abundances.^[48]

Behavior and life cycle

Muskrats (Ondatra zibethicus) exhibit primarily nocturnal and crepuscular activity patterns, with peak foraging and movement occurring around dusk and dawn, though they remain active throughout the day and do not hibernate.^[38] In summer, their 24-hour rhythm is typically bimodal, featuring major activity bursts between sunset and sunrise, while winter conditions may shift them toward more diurnal behavior to exploit daylight for feeding under ice.^[51] Year-round activity includes constructing and maintaining lodges or burrows, swimming, and diving for vegetation, with daily home range sizes varying from 0.1 to 1.5 hectares depending on habitat quality and population density.^[17] Socially, muskrats are largely solitary outside the breeding season, defending individual territories marked by scent glands and latrines, with aggression peaking during territorial disputes that can involve fighting, chasing, or vocalizations such as tail-slapping on water.^[17] Family units form during reproduction, consisting of a mated pair and their offspring, which share lodges or push-up dens until juveniles disperse at 1-2 months old; overcrowding in high-density populations may lead to maternal expulsion of young or dispersal to reduce competition.^[2] In severe winter conditions, multiple individuals—often unrelated—may communally occupy dens or lodges to conserve heat, though this tolerance is temporary and driven by survival needs rather than cooperative social structure.^[17] Dominance hierarchies emerge in dense populations, particularly among males during breeding, influencing access to mates and resources, but overall social interactions remain limited compared to more gregarious rodents.^[52]

Reproduction and development

Muskrats exhibit a high reproductive rate that varies with latitude and environmental conditions. In northern regions, breeding typically begins in March or April, with the first litters born in late April or early May, and continues through summer or early fall, producing 1–4 litters annually.^[38]^[17] In southern areas, breeding can occur year-round or from November to April, allowing for up to 6 litters per female in optimal conditions.^[53] Females are polygamous and usually reach sexual maturity at around one year of age, though some may breed as early as 6 months in favorable habitats.^[36]^[53] Copulation often occurs while submerged in water.^[53] Gestation lasts 25–30 days, after which females give birth to litters of 1–11 young (averaging 4–8), typically in a grass-lined chamber within a lodge or bank burrow.^[38]^[54]^[17] Newborns, weighing approximately 20–22 grams, are altricial: blind, with closed ears, and covered in sparse or fine fur.^[17] Young muskrats develop rapidly; their eyes open at 14–16 days, and they begin swimming around 10 days of age while starting to consume vegetation by 21 days.^[17]^[15] Weaning occurs at about 21–28 days, after which the kits become increasingly independent, dispersing from the natal site by 4–6 weeks.^[36]^[55] Females may evict subadults to reduce competition, contributing to high population turnover.^[2] Juveniles reach adult size in about 200 days but typically do not breed until the following year.^[11] This prolific reproduction supports rapid population recovery but also leads to cyclical fluctuations tied to habitat quality and density-dependent factors.^[16]

Predators and causes of mortality

Muskrats (Ondatra zibethicus) are preyed upon by a range of mammalian, avian, reptilian, and aquatic predators, with mink (Neovison vison) serving as a primary threat due to their proficiency in hunting semi-aquatic rodents in wetlands.^[42]^[38]^[3] Other mammalian predators include otters, raccoons (Procyon lotor), foxes, coyotes, bobcats (Lynx rufus), weasels, and domestic dogs or cats, which target muskrats both in water and on land.^[17]^[56] Avian predators such as great horned owls (Bubo virginianus), red-tailed hawks (Buteo jamaicensis), bald eagles (Haliaeetus leucocephalus), and marsh hawks (Circus hudsonius) frequently attack, particularly vulnerable juveniles or swimming individuals.^[38]^[17] Reptilian and aquatic predators like snapping turtles (Chelydra serpentina) and large predatory fish pose risks mainly to young muskrats near the water's edge or in shallow areas.^[57] Infectious diseases represent a significant non-predatory cause of mortality, with Tyzzer's disease (Clostridium piliforme infection) linked to mass die-offs, as documented in a 2017 event in northwest Ohio where it affected multiple individuals alongside septicemia in some cases.^[58]^[59] Other prevalent pathogens include tularemia (Francisella tularensis), cysticercosis from tapeworm larvae, and various bacterial or viral infections that contribute to episodic declines.^[59] Parasites, contaminants, and toxins also elevate mortality rates, though their impacts vary by region and environmental conditions.^[59] Human activities, particularly regulated hunting and trapping for fur, constitute a leading anthropogenic mortality factor, often limiting population growth in harvestable areas.^[36] Climatic extremes, such as severe winters causing ice entrapment or flooding that destroys lodges, alongside food scarcity and intraspecific competition during density peaks, further drive mortality, especially among juveniles where annual survival rarely exceeds 20-30%.^[36]^[60] Trauma from non-predatory sources, including vehicle collisions or drowning, accounts for additional losses in surveyed populations.^[60]

Human interactions

Economic uses and harvesting

Muskrats (Ondatra zibethicus) are harvested primarily for their fur, which serves as a key commodity in the North American fur trade due to its water-repellent underfur and durable guard hairs suitable for garments like coats.^[61] The species has historically been the most valuable semi-aquatic furbearer, generating millions in annual fur trade revenue across the continent.^[61] In British Columbia, muskrat pelts have accounted for up to 15% of total fur harvest value in past decades.^[62] The meat from harvested muskrats provides an additional economic use, processed for human consumption or sold as feed for domestic pets, particularly in areas where trapping is common.^[36] Trappers often retain the meat for personal use while selling pelts to dealers, contributing to local economies in rural and indigenous communities.^[36] Harvesting occurs mainly through regulated trapping seasons using body-gripping traps, foothold traps, or conibear traps set near lodges, burrows, or travel routes in wetlands.^[36] Annual harvest quotas and seasons vary by jurisdiction to manage populations, with peak trapping typically in fall and winter when pelts are prime.^[63] North American harvests peaked in the mid-20th century, exceeding several million pelts annually, but have since declined by over 75% in eastern regions since 1986 amid fluctuating pelt prices and population trends.^[64] For instance, Pennsylvania's reported take dropped from 720,000 muskrats in 1983 to 58,295 in 2010, reflecting broader continental patterns.^[65] Recent figures, such as 2,000 to 4,000 annually in Connecticut, indicate muskrats now rank low in economic importance for trappers in many states.^[63]^[66]

Conflicts and pest status

Muskrats (Ondatra zibethicus) cause significant conflicts with human activities through burrowing that undermines earthen structures such as pond dams, reservoirs, levees, and irrigation canals, leading to leaks, erosion, and potential flooding.^[67]^[36] In their native North American range, this activity has resulted in documented agricultural losses, including nearly $900,000 in damage to rice crops, fish reservoirs, and bait fish operations in Arkansas alone as of 1967, prompting targeted control efforts.^[68] They also consume aquaculture products like crayfish and mussels, as well as vegetation in farm ponds and wetlands, exacerbating economic impacts.^[36] As an invasive species in Europe, introduced in the early 20th century, muskrats pose heightened risks by burrowing into critical flood defenses, railways, and dams, with chewing damage to fish nets and traps in aquaculture settings.^[13] In the Netherlands, where dikes are vital for flood protection, muskrat density correlates directly with increased structural damage to levees and waterfronts, necessitating a national trapping program operational since 1941 that removes tens of thousands annually at a cost of approximately €35 million per year.^[69]^[70] This program, managed by water authorities, aims to mitigate flood risks but faces ongoing challenges from population rebounds and cross-border spread.^[71] In Germany and other regions, similar economic damages from infrastructure threats underscore their pest classification under EU invasive species regulations.^[13]^[72] Beyond structural harm, muskrats contribute to ecosystem disruptions by overgrazing aquatic vegetation and altering habitats, indirectly affecting biodiversity and native species in invaded areas.^[73] In both native and introduced ranges, they can vector diseases such as tularemia, though direct human health conflicts remain secondary to property and agricultural losses.^[36] Management strategies, including lethal trapping, have proven effective in reducing densities and associated damages, as evidenced by large-scale experiments in the Netherlands linking control efforts to lower incidence of burrows and breaches.^[74]

Role in ecosystems and management

Muskrats (Ondatra zibethicus) function as ecosystem engineers in wetland habitats through herbivory, burrowing, and construction of lodges and push-ups, which modify vegetation structure and enhance local plant diversity.^[75] ^[76] Their grazing activities create patches of open water amid dense emergent vegetation, such as cattails, transforming uniformly vegetated wetlands into heterogeneous mosaics that support varied aquatic communities.^[77] In some cases, muskrat foraging has been observed to reduce biomass of invasive plants like cattails (Typha spp.) and European frogbit (Hydrocharis morsus-ranae), potentially aiding in the control of non-native species proliferation.^[78] However, muskrats also exert negative pressures, including predation on freshwater mussels, with documented impacts on 26 species, 14 of which are threatened or endangered, exhibiting size-selective predation on certain vulnerable taxa.^[79] As prey, muskrats sustain a broad array of predators, including mink, raccoons, hawks, owls, coyotes, foxes, and bobcats, thereby supporting trophic dynamics in wetland food webs; mink populations, in particular, show dependence on muskrat abundance.^[38] ^[80] Their constructed lodges and burrows, once abandoned, provide refuge and nesting sites for other wildlife, contributing to habitat complexity.^[80] Population cycles and disturbances by muskrats influence broader wetland biodiversity, though effects vary by context, with some studies labeling them keystone or ecosystem engineers due to their capacity for habitat alteration at scales relevant to regional diversity drivers.^[81] ^[82] In native North American ranges, muskrats are managed primarily through regulated trapping for fur harvesting, though populations have declined in recent decades, prompting research into habitat changes like invasive Typha dominance as contributing factors.^[49] In introduced European populations, classified as invasive under EU Regulation 1143/2014, intensive control measures including trapping aim to mitigate damage to infrastructure such as dikes and waterways, with large-scale experiments demonstrating trapping's effectiveness in population reduction or eradication.^[72] ^[83] ^[74] Cost-benefit analyses in regions like the Netherlands support ongoing eradication efforts, balancing ecological risks against infrastructure protection.^[70]

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[28]
Common Muskrat - Ondatra zibethicus - New Hampshire PBS
The muskrat eats aquatic vegetation like cattails, sedges, rushes, water lilies and pond weeds. In some areas it also eats clams, mussels, snails, crayfish, ...Characteristics · Habitat · Diet
[29]
[PDF] Muskrat - NC Wildlife
Range and Distribution. Muskrats occupy much of the wetlands in the United States, but are absent from. Florida and rare in some southern states.
[30]
muskrat (Ondatra zibethicus) - Species Profile
The list of references for all nonindigenous occurrences of Ondatra zibethicus are found here. State, First Observed, Last Observed, Total HUCs with ...Missing: subspecies source
[31]
Introductions of aquatic rodents: lessons of the muskrat Ondatra ...
The muskrat Ondatra zibethicus is one of the semi-aquatic rodents that has been introduced into many areas of the world. It is regarded as a most successful ...Missing: etymology | Show results with:etymology<|control11|><|separator|>
[32]
Ondatra zibethicus - Global Invasive Species Database
Secondary spread has led to an invasive range throughout Europe and as far as China and Japan. Similar to beavers, they are considered ecosystem engineers, and ...
[33]
Europe agrees to step up the fight against invasive alien species
Jul 12, 2017 · The North American muskrat (Ondatra zibethicus) is a wetland species that creates burrows which can cause serious damage to railways, dams, and ...
[34]
[PDF] Distribution of invasive muskrats (Ondatra zibethicus) and impact on ...
The muskrat homeland is North America, from. Northern Canada and South Alaska through the United States, except the arid regions of the. Southwest and Texas, ...
[35]
Chromosome-level Genome of the Muskrat (Ondatra zibethicus)
Oct 7, 2022 · Although O. zibethicus is considered an invasive species in Europe and Asia, including France, Germany, Poland, Russian, Mongolia, etc. and is ...<|control11|><|separator|>
[36]
[PDF] Muskrats - usda aphis
Muskrats also cause damage by eating agricultural crops, other vegetation, and crayfish, mussels and other aquaculture products. Loss of vegetation from muskrat.Missing: diet | Show results with:diet
[37]
Muskrat | NC Wildlife
Scientific Name: Ondatra zibethicus ; Classification: Furbearer species ; Abundance: Found throughout the state; rare in coastal areas of southeastern NC.Missing: native | Show results with:native
[38]
Muskrat - NYSDEC
Muskrat foods will vary with the type of habitat. Marsh dwellers may eat aquatic plants such as cattails almost exclusively, whereas animals in large bodies of ...
[39]
Muskrat: Mammals: Species Information: Wildlife - Maine.gov
Habitat. In wetlands with dense emergent vegetation, with a preference for slow or still water, muskrats build small lodges out of aquatic plants, ...
[40]
[PDF] HABITAT SUITABILITY INDEX MODELS: MUSKRAT
Habitat preferences of the muskrat (Ondatra zibethicus) are described in this report, which is one of a series of Habitat Suitability Index (HSI) models.
[41]
[PDF] Muskrat in New Jersey
A 50:50 ratio of brackish water and dense vegetative cover makes for ideal habitat. Clay soils are particularly desirable and allow them to construct their ...
[42]
Muskrat | Minnesota DNR
The muskrat is found throughout of Minnesota. It lives in marshes, ponds, and streams that have many water plants. Several hundred muskrats can live in a single ...
[43]
Home ranges and space use of muskrats Ondatra zibethicus in ...
Dec 1, 2010 · Home ranges were highly linear and confined to stream bank edges. Contrary to our prediction, muskrats did not freely move to upland habitat ( ...
[44]
Summer foraging patterns and diet selection of muskrats inhabiting ...
These data suggest that predator avoidance behavior strongly influenced muskrat foraging movements, and that muskrats attempted to maximize feeding efficiency ...Missing: strategies | Show results with:strategies
[45]
[PDF] Direct Observation of Muskrat Feeding on Crayfish
Ondatra zibethicus (L.) (Common Muskrat, hereafter Muskrat) is often considered herbivorous, feeding mainly on aquatic herbaceous plants, such as Typhus spp.
[46]
Population dynamics of muskrats (Ondatra zibethicus) and American ...
Published estimates for muskrat population cycles in Canada range from 3 to 13 years, but the majority of cycles are 8–9 years long (Erb et al. 2000) ...
[47]
[PDF] Landscape Ecology Influence On Population Dynamics And Gene ...
Apr 29, 2022 · Geographic variation in population cycles of Canadian muskrats (Ondatra zibethicus) 78:8. Page 30. 20. Errington, P. L. 1941. Versatility in ...
[48]
Historical surveys reveal a long‐term decline in muskrat populations
Muskrat numbers have been shown to fluctuate periodically; thus, it is possible that low house counts may be reflecting a low phase in a normal population cycle ...
[49]
Impact of invasive Typha and wetland interspersion on muskrat ...
Muskrat (Ondatra zibethicus) populations are declining in North America. The exact cause of these declines is largely unknown. Along a similar timeframe, ...
[50]
[PDF] Declines in Muskrat (Ondatra zibethicus) Population Density in ...
Overall, these data suggest evidence for low but stable populations of muskrats in the majority of PEI marshes examined, substantiating trapper opinions of low ...<|separator|>
[51]
Daily and seasonal activity patterns of the muskrat Ondatra ...
Aug 6, 2025 · Activity patterns of the muskrat Ondatra zibethicus L. were examined during summer and winter in Delta Marsh, Manitoba, Canada (50°11′N, ...Missing: sensory | Show results with:sensory
[52]
Behavioral Shifts of an Insular Muskrat (Ondatra zibethicus ...
Jun 1, 2025 · In mainland populations, muskrats become aggressive during the summer breeding season and maintain dominance hierarchies that push low-ranking ...
[53]
[PDF] Muskrats - South Carolina Department of Natural Resources
Muskrats are sexually mature after 6 months. Copulation usually takes place while the animals are submerged.
[54]
Muskrat | North Dakota Game and Fish
Breeding Season, April-August ; Gestation Period, 25-30 days ; Litter Size, 1-11 (average 6-7) - Muskrats are capable of producing more than one litter per year.
[55]
Muskrat - Hinterland Who's Who
Weaning, or making the transition from the mother's milk to other foods, occurs at about three weeks, and juveniles are essentially independent of their parents ...
[56]
[PDF] Muskrats - Washington Department of Fish and Wildlife
Muskrats have many predators, including mink (a major predator), otters, bobcats, house cats, domestic dogs, coyotes, foxes, large hawks and owls, and ...<|separator|>
[57]
[PDF] Muskrat - New York Sea Grant
Other physical characteristics that make muskrats well-suited to aquatic habitats are their fur, mouth, and eyes. A special layer of fur traps air to insulate.Missing: adaptations | Show results with:adaptations
[58]
Mortality due to Tyzzer's Disease of Muskrats (Ondatra zibethicus) in ...
Oct 1, 2019 · Abstract. In 2017, we investigated a mortality event of muskrat (Ondatra zibethicus) in northwest Ohio, US, and determined the causes of death ...Missing: studies | Show results with:studies
[59]
A Review of Pathogens, Diseases, and Contaminants of Muskrats ...
May 15, 2020 · A wide diversity of contaminants, toxins, and pathogens were reported in muskrats, with the most common diseases being cysticercosis, tularemia, Tyzzer's ...
[60]
Surveillance for diseases, pathogens, and toxicants of muskrat ...
Dec 9, 2021 · We identified multiple causes of mortality in muskrats, but trauma (8/26), Tyzzer's disease (5/6), and cysticercosis (5/26) were the most common ...Missing: scientific | Show results with:scientific
[61]
Habitat Suitability Index Models: Muskrat | U.S. Geological Survey
The muskrat (Ondatra zibethicus) is the most valuable semi-aquatic furbearer in North America, with a total fur trade income in the millions of dollars (Willner ...Missing: value industry
[62]
[PDF] muskrat.pdf - Gov.bc.ca
The proportion of total fur harvest value contributed by muskrats in British Columbia has been as high as 15 percent historically, and as high as 12 percent in ...
[63]
Muskrat - CT.gov
They are considered an important furbearer resource in terms of the number harvested and economic value.
[64]
Do Trends in Muskrat Harvest Indicate Widespread Population ...
Aug 7, 2025 · Muskrat harvest has declined by approximately 75% since 1986 in eastern North America, despite a recent resurgence in pelt prices. Recent ...Missing: meat | Show results with:meat
[65]
Many factors may contribute to steep, decades-long muskrat ...
Jun 8, 2020 · A number of theories to explain the drop in muskrat population have been proposed, including habitat loss, predation, environmental contamination and diseases.
[66]
Muskrat Uses, Alaska Department of Fish and Game
Muskrats are one of about 12 furbearers trapped in Alaska and are near the bottom of the list in economic importance, although muskrat fur is beautiful and ...
[67]
Muskrat Conflicts and Damage - Forestry and Natural Resources
The most serious conflicts between humans and muskrats occur when muskrats burrow into the banks of farm ponds, reservoirs and other earthen water-retaining ...Missing: Ondatra zibethicus infrastructure
[68]
Muskrat control and damage prevention - eScholarship
Damage caused by muskrats to rice crops, food fish, and bait fish reservoirs In Arkansas was estimated in 1967 to be almost $900,000. A control program begun in ...Missing: conflicts infrastructure<|separator|>
[69]
Damage to dykes and levees in the Netherlands is extensive and ...
A national control program currently traps and kills tens of thousands of muskrats each year. The costs (annually about € 35M) as well as concerns raised by ...
[70]
[PDF] COST-BENEFIT ANALYSIS OF INVASIVE MUSKRAT CONTROL IN ...
Muskrats threaten public safety in The Netherlands by burrowing into water-retention structures, and a control programme has been in effect since 1941.
[71]
Management of Invasive Coypu and muskrAt in Europe
Coypu and muskrat management operations are a core activity of the Dutch Water Authorities, where trapping operations help minimise the muskrat population and ...<|separator|>
[72]
[PDF] Dataflows in support of cross-border management of muskrat ...
Sep 8, 2024 · It is now the most widespread invasive alien mammal on the European continent (Tedeschi et al. 2022). Coypu Myocastor coypus (Molina, 1782), ...Missing: conflicts | Show results with:conflicts
[73]
Distribution of invasive muskrats (Ondatra zibethicus) and impact on ...
Aug 6, 2025 · The muskrat (Ondatra zibethicus L.) after being introduced to Europe quickly colonized new areas. They occupied Northern, Eastern and ...<|separator|>
[74]
A Large‐Scale Experiment to Evaluate Control of Invasive Muskrats
We report on a carefully designed and large management experiment to test hypotheses about the effectiveness of muskrat control by trapping.
[75]
Local disturbance by muskrat, an ecosystem engineer, enhances ...
Oct 5, 2020 · This study demonstrates that muskrat disturbance influences wetland plant diversity at scales relevant to regional drivers of plant diversity.
[76]
[PDF] Muskrat (Ondatra zibethicus) Disturbance to Vegetation and ...
—The muskrat (Ondatra zibethicus) is a wetland mammal whose disturbance activities include grazing, burrowing and lodge construction. We evaluated the effects ...
[77]
Muskrats (Ondatra zibethicus) in treatment wetlands - ScienceDirect
Muskrat grazing can change treatment wetlands from being densely vegetated to a patchwork of open and emergent areas.
[78]
Muskrats may be key to solving invasive aquatic plant problems ...
Sep 12, 2025 · Both muskrats and MDAs were effective at reducing invasive plant biomass. However, the researchers noticed some differences in muskrat vs. human ...
[79]
Assessing muskrat predation on a freshwater mussel assemblage in ...
26 species, 14 threatened or endangered, were prey to muskrat. Size selective predation occurred on three endangered species and one candidate species.
[80]
Muskrat | Wildlife Illinois
Muskrats forage for food near their dens and tend not to travel far. ... Additionally, abandoned muskrat burrows provide homes for several other species.Missing: strategies | Show results with:strategies
[81]
How do muskrats Ondatra zibethicus affect ecosystems? A review of ...
Muskrats Ondatra zibethicus are reported to have wide-ranging effects on wetland habitats, sometimes earning them the labels 'keystone species' or 'ecosystem ...
[82]
How do muskrats Ondatra zibethicus affect ecosystems? A review of ...
Aug 5, 2025 · Muskrats Ondatra zibethicus are reported to have wide‐ranging effects on wetland habitats, sometimes earning them the labels 'keystone ...<|separator|>
[83]
Evidence for the effectiveness of controlling muskrat (Ondatra ...
May 11, 2019 · Invasive alien species (IAS) are a worldwide issue and in many cases demand some form of population management. The muskrat (Ondatra zibethicus ...