Mustela furo (ferret)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Biology and Ecology
- Means of Movement and Dispersal
- Pathway Causes
- Impact Summary
- Economic Impact
- Environmental Impact
- Threatened Species
- Risk and Impact Factors
- Uses List
- Detection and Inspection
- Prevention and Control
- Links to Websites
- Principal Source
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Mustela furo Linnaeus, 1758
Preferred Common Name
Other Scientific Names
- Martes furo (Linnaeus)
- Mustela furo
- Putorius putorius furo L.
International Common Names
- English: domestic ferret; fitch; New Zealand fitch
Summary of InvasivenessTop of page
The ferret, Mustela furo, is a small carnivorous mammal in the family Mustelidae. It is the domesticated form of the European polecat (Mustela putorius) (or possibly the eastern European steppe polecat (M. eversmannii) or both). It is kept in many countries for hunting or as a pet (and occasionally for fur farming), and has sometimes been released into the wild to control rabbits. Escaped or released ferrets have established feral populations in New Zealand and parts of Europe. They are a threat to native prey species, particularly ground-nesting and flightless birds, and in Europe they pose a threat to native polecats by hybridization. Ferrets can also act as a vector for bovine tuberculosis.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Mammalia
- Order: Carnivora
- Family: Mustelidae
- Genus: Mustela
- Species: Mustela furo
Notes on Taxonomy and NomenclatureTop of page
'Ferret' is the name given to the domesticated animal derived from the albino form of the polecat. There is some debate as to whether the ferret was derived from the western European polecat (Mustela putorius) or the eastern European steppe polecat (M. eversmannii), or is a hybrid of both (Department of Conservation, 2005; Corbett and Ovenden, 1980; Howes, 1980; King, 1990; Mathews, 1982). Ferrets are variously considered to be a separate species (ISSG, 2017), or the same biological species as the western polecat (M. putorius), or a subspecies of it, M. putorius furo (King, 1990); they do interbreed with western polecats in the wild. The resulting hybrids are sometimes indistinguishable from the wild polecat (Corbett and Ovenden, 1980; Howes, 1980). This datsheet uses M. putorius furo as the preferred name, following Wilson and Reeder (2005) and ITIS (2017).
DescriptionTop of page
Ferrets are sexually dimorphic; male ferrets weigh between 1000g and 2000g, and females between 600g and 900g (Landcare Research, 2008). They have a long and slender body which is 48cm to 56cm long (including the tail). They have large canine teeth (34 teeth in total). Each paw has a set of five non-retractable claws (Duda, 2003). Ferrets have three basic colour variations: dark (similar to the polecat), white underfur with brownish guard hairs (referred to as sandy or pastel), and all white (albino). All three of these variations are found in New Zealand (Jeffares, 1986). In Europe, wild-type colour variations are more common in populations that have been feral for several generations.
DistributionTop of page
The polecat, Mustela putorius, of which the ferret is usually considered to be the domesticated form, is native to Eurasia. Domestic ferrets are kept in many countries, and escaped or released ones have established feral populations in New Zealand and parts of Europe, but not in North America or (except for temporary estabishments) Australia. See the Distribution table for more details.
Note that the Distribution table only lists feral populations, not captive/domestic ones.
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|-Canary Islands||Present||Introduced||Long, 2003||Probably introduced successfully|
Central America and Caribbean
|Isle of Man (UK)||Present||Introduced||Long, 2003|
|Italy||Present||Present based on regional distribution.|
|Portugal||Present||Present based on regional distribution.|
|-Azores||Present||Introduced||1500s||Invasive||Pitta Groz et al., 2002|
|Spain||Present||Present based on regional distribution.|
|Australia||Present||Introduced||Long, 2003||Frequent escapes have not resulted in permanent populations|
|New Zealand||Present||Introduced||1880s||Invasive||Long, 2003|
History of Introduction and SpreadTop of page
There is some debate as to whether the domestic ferret was derived from the western European polecat (Mustela putorius) or the eastern European steppe polecat (M. eversmannii), or is a hybrid of both (Department of Conservation, 2005; Corbett and Ovenden, 1980; Howes, 1980; King, 1990; Mathews, 1982). Ferrets were first known in Palestine some 1000 years BC, used for fighting rodents and hunting rabbits, and they have been known in Europe since at least the Middle Ages (Kowalski, 1976). They are now kept in many countries; outside Europe the most noteworthy feral populations are in New Zealand, where ferrets were released in large numbers in the 1880s and 1890s (Long, 2003) in an attempt to control the rabbit population (Atkinson, 2001). The first introductions to Australia in the 1880s were also to control rabbits, but despite continuing escapes, permanent populations have not become established (Long, 2003).
Risk of IntroductionTop of page
As domestic ferrets have been selectively bred in captivity for hundreds of years for qualities of docility and tameness, their capacity to survive in the wild may be limited to some degree (Davison et al., 1999). However, pet ferrets and farmed ferrets do escape, and while some may be unable to survive in the wild, there are always some which are able to adapt (Department of Conservation, 2005).
HabitatTop of page
The native habitat of ferrets is forested and semi-forested areas near water sources (Duda, 2003). In Europe their habitats include dune systems with large rabbit populations. In New Zealand, they are generally found in grasslands, scrub, pasture land, forest fringes and urban and suburban areas (Landcare Research, 2008; Atkinson, 2001; Department of Conservation, 2005; Duda, 2003); recent reports indicate that ferrets may be penetrating into deep forest land in some locations (Department of Conservation, 2005). Den sites can be found in gorse, dense scrub, rabbit holes, buildings, rubbish piles, and haybarns (Ragg, 1998; Jeffares, 1986). Dispersing juvenile ferrets have been found under low-growing shrubs and in overgrown stream channels and river banks (Ragg, 1998).
Habitat ListTop of page
|Coastal dunes||Present, no further details|
|Cultivated / agricultural land||Present, no further details|
|Disturbed areas||Present, no further details|
|Urban / peri-urban areas||Present, no further details|
|Natural forests||Present, no further details|
|Natural grasslands||Present, no further details|
|Scrub / shrublands||Present, no further details|
Biology and EcologyTop of page
Ferrets are polygynous, iteroparous, sexual, viviparous and altricial (Duda, 2003). In the notrthern hemisphere, male domestic ferrets go into rut between December and July, and females go into heat between March and August. Males are ready to breed when they develop a discoloured, yellowish undercoat, caused by an increase in the oil production of the skin glands. A female in estrous is identifiable by a swollen pink vulva due to an increase in estrogen. Healthy domestic ferrets can have up to three successful litters per year, and up to 15 kits. Gestation length is about 42 days, and there are eight weeks of parental care. Female kits reach sexual maturity at six months old (Duda, 2003). Unlike some other mustelids, ferrets do not show delayed implantation (Hinds et al., 2000).
In New Zealand, ferrets reproduce between August and January, producing up to nine young from two litters (Hinds et al., 2000), although one litter is usual (Hinds et al., 2000). Juveniles disperse at three months of age, and sexual maturity is reached at between 8 and 12 months (Landcare Research, 2008).
The life expectancy of juvenile ferrets is estimated to be 1.3 years (Clapperton, 2001). Ferrets live for about two to four years in the wild (Landcare Research, 2008), while in captivity they can live for 8-14 years (King, 1990).
Ferrets are largely nocturnal. In the high country of New Zealand, their home range averages 80 hectares, whereas in the lowlands, male home ranges average 30 hectares, and those of females 12 hectares. They are strong swimmers, and will readily cross waterways to new areas (Landcare Research, 2008).
In New Zealand, young ferrets emerge from the nest in the first two weeks of January, and dispersal occurs in early to mid-March (Byrom, 2002). Large influxes of juveniles are therefore observed in late summer and autumn. Juvenile ferrets will move a median distance of 5km from their natal site, with no sex-specific differences in dispersal (Byrom, 2002).
Dens are often shared with other ferrets, which may increase the transmission of bovine tuberculosis (Ragg, 1998).
In New Zealand, rabbits are the main food of ferrets, and are thought to be the main factor determining where they are found and in what numbers. Ferrets also eat native birds, even when rabbits are plentiful (Department of Conservation, 2005), and will also prey on hares, possums, bird eggs, lizards, hedgehogs, frogs, eels and invertebrates. They will scavenge the carcasses of other ferrets, hedgehogs, cats and possums. In the Scottish islands they have also been observed scavenging on lamb carcasses. Diet varies with food availability, and male ferrets eat more rabbits than do females. Ferrets are capable of switching to other prey when rabbit numbers are controlled (Landcare Research, 2008). Those in New Zealand forests tend to have more rats in their diet, and no birds (Clapperton, 2001). Some seasonal variation in diet has also been observed. Rabbits and hares will dominate in summer, and rodents in autumn and winter. Birds are eaten year-round, but more in spring and summer (King, 1990).
Means of Movement and DispersalTop of page
Once ferrets are present in an area, they can spread naturally. They are strong swimmers, and will readily cross waterways to new areas (Landcare Research, 2008).
Although the presence of domestic ferrets in a country is usually intentional (as pets or for fur farming), wild populations can form when individuals escape (Department of Conservation, 1999; Corbett and Ovenden, 1980).
Ferrets are widely kept as pets, and have been imported to some countries (for example New Zealand) for fur farming (Long, 2003; Department of Conservation, 1999); farmed or pet ferrets have sometimes been released deliberately (Department of Conservation, 1999). There are concerns that the popularity of pet ferrets is widening their distribution in New Zealand (Department of Conservation, 1999).
Ferrets were also introduced to New Zealand in an attempt to control the rabbit population (Atkinson, 2001).
Pathway CausesTop of page
Impact SummaryTop of page
Economic ImpactTop of page
Ferrets are (at least in New Zealand) a known vector for bovine tuberculosis (Mycobacterium bovis), which can be transmitted by direct contact or via contamination of pasture and food (Ragg, 1998), although brushtail possums (Trichosurus vulpecula) are the main maintenance host (Lisle et al., 2002).
Environmental ImpactTop of page
In their introduced range, ferrets threaten a variety of native wildlife, for example, ground-nesting and flightless birds in New Zealand (Department of Conservation, 2005; Norbury, 2001; Clapperton, 2001). They have also contributed to the decline of seabird populations in the Azores (Pitta Groz et al., 2002), and reduced bird populations in the Scottish islands (Lever, 1985; Corbett and Southern, 1977). In Europe they are sympatric with wild polecats and there is a danger of hybridization (Davison et al., 1999).
Threatened SpeciesTop of page
|Threatened Species||Conservation Status||Where Threatened||Mechanism||References||Notes|
|Megadyptes antipodes (yellow-eyed penguin)||EN (IUCN red list: Endangered) EN (IUCN red list: Endangered); USA ESA listing as threatened species USA ESA listing as threatened species||New Zealand||Predation||US Fish and Wildlife Service, 2010|
Risk and Impact FactorsTop of page Invasiveness
- Proved invasive outside its native range
- Has a broad native range
- Is a habitat generalist
- Capable of securing and ingesting a wide range of food
- Highly mobile locally
- Has high reproductive potential
- Negatively impacts animal health
- Threat to/ loss of native species
- Pest and disease transmission
UsesTop of page
Ferrets were originally domesticated for the hunting of rodents and rabbits in Europe (Jurek, 1998). They have also been released into the wild to control rabbits, for example in Australia (Long, 2003). Since the 1970s, they have begun to gain in popularity as pets in the USA and around the world (Wenker and Christen, 2002; Jurek, 1998). They also have a limited history as fur farmed animals in the USA (Jurek, 1998) and in New Zealand (Department of Conservation, 1999), and in recent decades have been used as research animals in the medical field, for example in influenza research (Jurek, 1998).
Uses ListTop of page
- Biological control
- Pet/aquarium trade
- Research model
- Sport (hunting, shooting, fishing, racing)
Detection and InspectionTop of page
Trained dogs can be used to find and monitor ferrets in farmland, although a programme in New Zealand was discontinued because it was unable to compete cost-effectively with trapping for ferret control -- the dogs were not working regularly enough to keep their interest and reliability (Ragg, 2010). Snow-tracking has also been used to detect ferret activity in New Zealand (King, 1994), and tracking tunnels are also used to monitor mustelid abundance (Gillies and Williams, 2013).
Prevention and ControlTop of page
More detailed information on prevention and control is provided by ISSG (undated).
Ferret control has traditionally been done by trapping in New Zealand, using meat (e.g. rabbit) as a lure. However, this can be labour-intensive, time-consuming and costly (Spurr et al., 2005), and raises ethical issues (ISSG, undated); many kill traps are ineffective at killing animals quickly and humanely (Warburton and O'Connor, 2004). Compared with kill or leg-hold traps, live traps have the advantages of being more humane (if checked regularly) and causing less harm to non-target species (Ragg, 2010).
Traps can be baited with an artificial scent lure (Clapperton, 2001). Ferrets are known to be less easily trapped in spring, and culling in autumn gives more success than culling in spring (Barlow and Norbury, 2001). Landcare Research (2008) state that setting traps near vegetation cover, rabbit signs or other animal tracks improved capture rates, while research cited by Clapperton (2001) found that ferrets were most often caught in traps set close to waterways.
In countries where ferrets are invasive, ferret-free islands should be kept ferret-free. This can be done by public education and prohibiting the transport and transfer of ferrets to these islands (King, 1994).
There is some interest in developing the canine distemper virus as a potential form of biological control (Clapperton, 2001).
There has been research in New Zealand on chemical control of ferrets, but the pesticides used are now banned or restricted by international agreements.
Ferret populations recover quickly from control operations, mostly due to reinvasion from other areas. A reduction in ferret numbers will also increase the survival chances of the remaining ferrets. This means that ongoing control is required to maintain ferret numbers at a low level to protect vulnerable species (Landcare Research, 2008). Byrom (2002) suggests that the most effective time for ferret control is following dispersal of juveniles (late autumn in New Zealand). Young ferrets have been observed to move up to 45 km from their home territory, and are more likely to colonise areas that had had predator control the previous spring. It is suggested that predator control should be carried out in autumn rather than spring (Landcare Research, 2008).
Trials have been carried out in New Zealand to attempt to condition ferrets to avoid some prey species, such as native birds, but the initial results were disappointing (Parkes and Murphy, 2004).
Also in New Zealand, there have been attempts to reduce the impacts of ferrets and other predators on threatened birds by modifying the habitat around bird breeding sites. For example, the Department of Conservation has planted buffer zones of long grass around yellow-eyed penguin (Megadyptes antipodes) coastal grassland breeding areas and removed willows from braided riverbed habitat where stilts (Himantopus) and dotterels nest. Habitat modification lowered the rates of predation in the braided riverbed habitat of the MacKenzie Basin but not the coastal grassland habitat of the Otago Peninsula. Habitat modification is believed to have very limited applicability for farmland areas (Ragg, 2010).
ReferencesTop of page
Corbett GB, Ovenden D, 1980. The Mammals of Britain and Europe. London, UK: Collins, 247 pp.
Corbett GB, Southern HN, 1977. The Handbook of British Mammals. London, UK: Blackwell.
Davison A, Birks JDS, Griffiths HI, Kitchener AC, Biggins D, Butlin RK, 1999. Hybridization and the phylogenetic relationship between polecats and domestic ferrets in Britain. Biological Conservation, 87:155-161.
Department of Conservation, 1999. What can we do about ferrets? A public discussion document. Wellington, New Zealand: Department of Conservation.
Department of Conservation, 2005. Animal Pests: Ferrets. Wellington, New Zealand: Department of Conservation.
Duda J, 2003. Mustela putorius furo: domestic ferret. Animal Diversity Web. Ann Arbor, Michigan, USA: University of Michigan Museum of Zoology. http://animaldiversity.ummz.umich.edu/site/accounts/information/Mustela_putorius_furo.html
Gillies C, Williams D, 2013. DOC tracking tunnel guide v2.2: Using tracking tunnels to monitor rodents and mustelids. Hamilton, New Zealand: Department of Conservation, Science & Capability Group, 14 pp. http://www.doc.govt.nz/Documents/science-and-technical/inventory-monitoring/im-toolbox-animal-pests-using-tracking-tunnels-to-monitor-rodents-and-mustelids.pdf
Hinds LA, Williams CK, Pech RP, Spratt DM, Robinson AJ, Reubel GH, 2000. Feasibility of immunocontraception for managing stoats in New Zealand. Science for Conservation, No. 158:109 pp. http://doc.org.nz/Documents/science-and-technical/sfc158.pdf
Howes CA, 1980. Aspects of the history and distribution of polecats and ferrets in Yorkshire and adjacent areas. Naturalist, 105:3-16.
ISSG, 2017. Global Invasive Species Database (GISD). Invasive Species Specialist Group of the IUCN Species Survival Commission. http://www.issg.org/database
ISSG, undated. Management: Ferret (Mustela furo). Invasive Species Specialist Group of the IUCN Species Survival Commission, 8 pp. http://issg.org/database/species/reference_files/musfur/manmusfur.doc
ITIS, 2017. Integrated Taxonomic Information System (ITIS). Integrated Taxonomic Information System. http://www.itis.gov/
Jeffares R, 1986. The feral ferret in New Zealand. New Zealand Wildlife, 10:43-46.
Jurek RM, 1998. A review of national and California population estimates of pet ferrets. Sacramento, California, USA: Department of Fish and Game, Wildlife Management Division, 11 pp. [Bird and Mammal Conservation Program Report, 98-09.] https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=83826
King CM, 1990. The Handbook of New Zealand Mammals, 1st Edition. Auckland, New Zealand: Oxford University Press, 600 pp.
King CM, 1994. Monitoring and Control of Mustelids on Conservation Lands: Part 1: Planning and Assessing an Operation. Wellington, New Zealand: Department of Conservation, vi + 36 pp. [Department of Conservation Technical Series No. 3.] http://www.doc.govt.nz/upload/documents/science-and-technical/docts03.pdf
Kowalski K, 1976. Mammals, an outline of theriology. Warsaw, Poland: Panstwowe Wydawnicto, Naukowe.
Landcare Research, 2008. Ferret and stoat research. Lincoln, New Zealand: Landcare Research.
Lisle GW de, Bengis RG, Schmitt SM, O'Brien DJ, 2002. Tuberculosis in free-ranging wildlife: detection, diagnosis and management. Revue Scientifique et Technique - Office International des Épizooties, 21(2):317-334. http://www.oie.int/doc/ged/D517.PDF
Mathews LH, 1982. Mammals in the British Isles. London, UK: Collins.
Norbury G, 2001. Conserving dryland lizards by reducing predator-mediated apparent competition and direct competition with introduced rabbits. Journal of Applied Ecology, 38:1350-1361.
Pitta Groz M, Pereira JC, Silva AG, 2002. Invasive alien species as the main threat to Azores seabird populations. In: Proceedings of Workshop on invasive alien species on European islands and evolutionary isolated ecosystems, Horta, Azores, Portugal, 10 October 2002.
Ragg J, 1998. The denning behaviour of feral ferrets (Mustela furo) in a pastoral habitat, South Island, New Zealand. Journal of Zoology, 246(4):443-486. [Special section: Communications from the Mammal Society - No. 77.] http://dx.doi.org/ 10.1111/j.1469-7998.1998.tb00185.x
Ragg JR, 2010. Ferret Control Manual. Wellington, New Zealand: Animal Health Board, 55 pp. http://www.tbfree.org.nz/Portals/0/Best%20Practice%20Ferret%20Control%20Manual%202010.pdf
Spurr EB, Ogilvie SC, Morse CW, Young JB, 2005. Development of a toxic bait for control of ferrets (Mustela furo) in New Zealand. New Zealand Journal of Zoology, 32(2):127-136. http://dx.doi.org/10.1080/03014223.2005.9518404
US Fish and Wildlife Service, 2010. In: Endangered and Threatened Wildlife and Plants; Determination of Threatened Status for Five Penguin Species. 75(148) US Fish and Wildlife Service, 45497-45527. http://www.gpo.gov/fdsys/pkg/FR-2010-08-03/pdf/2010-18884.pdf
Warburton B, O'Connor C, 2004. Research on vertebrate pesticides and traps: do wild animals benefit? ATLA, Alternatives to Laboratory Animals [The three Rs at the beginning of the 21st century. Proceedings of the fourth world congress on alternatives and animal use in the life sciences, New Orleans, LA, USA, 11-15 August 2002.], 32(Supp 1A):229-234.
Wilson DE, Reeder DM, 2005. Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed.). Baltimore, Maryland, USA: Johns Hopkins University Press, 2142 pp. http://www.bucknell.edu/msw3/.
ContributorsTop of page
03/03/17: In-house revision at CABI (without updated literature search).
Reviewed by: Dr. Sugoto Roy Coordinator, Hebridean Mink Project Central Science Laboratory, Sand Hutton,York UK, 2010
Distribution MapsTop of page
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