Mustelidae

Mustelids
Fossil range: Early Miocene–Recent
Longtail Weasel
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Superfamily: Musteloidea
Family: Mustelidae
G. Fischer de Waldheim, 1817
Subfamilies

Lutrinae
Melinae
Mellivorinae
Taxideinae
Mustelinae

Mustelidae or Mustelids (from Latin mustela, weasel), commonly referred to as the weasel family, are a family of carnivorous mammals. The Mustelidae are a diverse family and the largest in the order Carnivora, at least partly because this family has in the past been a catch-all category for many early or poorly differentiated taxa.[1]

Contents

Variety

Sthenictis sp. (American Museum of Natural History)

The Mustelidae in general are phylogenetically relatively primitive and so were difficult to classify until genetic evidence started to become available. The increasing availability of such evidence may well result in some members of the family being moved to their own separate families, as has already happened with the skunks, previously considered to be members of the mustelid family.

Mustelids vary greatly in size and behavior. The least weasel is not much larger than a mouse. At the other end of the scale, giant otter can measure up to 2.4 metres (7.9 ft) in total length and sea otters can exceed 45 kilograms (99 lb). The wolverine can crush bones as thick as the femur of a moose to get at the marrow, and has been seen attempting to drive bears away from their kill. The sea otter uses rocks to break open shellfish to eat. The marten is largely arboreal, while the badger digs extensive networks of tunnels, called setts. Some mustelids have been domesticated. The ferret and the tayra are kept as pets (although the tayra requires a Dangerous Wild Animals licence in the UK), or as working animals for hunting or vermin control. Others have been important in the fur trade. The mink is often raised for its fur.

As well as one of the most species-rich families in the order Carnivora, mustelidae is one of the oldest. Mustelid-like forms first appeared about 40 million years ago, roughly coinciding with the appearance of rodents. The direct ancestors of the modern mustelids first appeared about 15 million years ago.

Characteristics

Within a large range of variation, the mustelids exhibit some common characteristics. They are typically small animals with short legs, short round ears, and thick fur. Most mustelids are solitary, nocturnal animals, and are active year-round.[2]

Mustelids, with the exception of the sea otter,[3] have anal scent glands that produce a strong-smelling secretion the animals use for sexual signaling and for marking territory. The most developed of these scent glands are found in skunks (Mephitinae), which were moved into a new family, Mephitidae, following DNA analysis.[4]

Most mustelid reproduction involves embryonic diapause. The embryo does not immediately implant in the uterus, but remains dormant for a period of time. No development takes place as long as the embryo remains unattached to the uterine lining. As a result, the normal gestation period is extended, sometimes up to a year. This allows the young to be born under more favorable environmental conditions. Reproduction has a large energy cost and it is to a female's benefit to have available food and mild weather. The young are more likely to survive if birth occurs after previous offspring have been weaned.

Mustelids are predominantly carnivorous, although some will sometimes eat vegetable matter. While not all mustelids share an identical dentition, they all possess teeth adapted for eating flesh, including the presence of shearing carnassials. Although there is variation between species, the most common dental formula is:[2]

Dentition
3.1.3.1
3.1.3.2

Ecology

Several members of the family are aquatic to varying degrees, ranging from the semi-aquatic mink, the river otters, and the highly aquatic sea otter. The sea otter is one of the few non-primate mammals known to use a tool while foraging. It uses "anvil" stones to crack open the shellfish that form a significant part of its diet. It is a "keystone species", keeping its prey populations in balance so some do not outcompete the others and they do not destroy the kelp in which they live.

The black-footed ferret is entirely dependent on another keystone species, the prairie dog. A family of four ferrets will eat 250 prairie dogs in a year. The ferrets require a prairie dog colony of 500 acres (2 km²) to maintain a stable population to support their predation.

The Mongoose and the meerkat bear a striking resemblance to many mustelids but belong to a distinctly different suborder - the Feliformia (all those carnivores sharing more recent origins with the Felidae) and not the Caniformia (those sharing more recent origins with the Canidae). Because the mongoose and the mustelids occupy similar ecological niches, convergent evolution has led to some similarity in form and behavior.

Relationship with humans

Detail from Leonardo da Vinci's "Lady with an ermine" (actually a ferret).

Several mustelids, including the mink, the sable (a type of marten) and the stoat (ermine), boast exquisite and valuable furs and have been accordingly hunted since prehistoric times. Since the early middle-ages the trade in furs was of great economic importance for northern and eastern European nations with large native populations of fur-bearing mustelids, and was a major economic impetus behind Russian expansion into Siberia and French and English expansion in North America. In recent centuries fur farming, notably of mink, has also become widespread and provides the majority of the fur brought to market.

One species, the Sea Mink (Neovison macrodon) of New England and Canada, was driven to extinction by fur trappers. Its appearance and habits are almost unknown today because no complete specimens can be found and no systematic contemporary studies were conducted.

The sea otter, which has the densest fur of any animal, narrowly escaped the fate of the sea mink. The discovery of large populations in the North Pacific was the major economic driving force behind Russian expansion into Kamchatka, the Aleutian islands and Alaska, as well as a cause for conflict with Japan and foreign hunters in the Kuril Islands. Together with widespread hunting in California and British Columbia, the species was brought to the brink of extinction until an international moratorium came into effect in 1911.

Today some mustelids are threatened for other reasons. Sea otters are vulnerable to oil spills and the indirect effects of overfishing; the black-footed ferret, a relative of the European polecat, suffers from the loss of American prairie; and wolverine populations are slowly declining because of habitat destruction and persecution. The rare European mink Mustela lutreola is one the most endangered mustelid species.[5]

One mustelid, the domestic ferret (Mustela putorius furo), has been domesticated since ancient times, originally for hunting rabbits and pest control.

Family members

Mustelidae has variously included up to five subfamilies (Lutrinae, Melinae, Mellivorinae, Taxideinae, Mustelinae). While some recent research[6] suggests Mustelidae should include only two extant subfamilies as follows:

FAMILY MUSTELIDAE (57 species in 22 genera)

More recent research, published in 2008, suggests that the Mustelinae subfamily are not a true grouping. Instead, this research suggests that the Mustelidae are divided into four major clades and three, much smaller, lineages. The early mustelids appear to have undergone two rapid bursts of diversification in Eurasia, with the resulting species only spreading to other continents later.[7] This study of the mitochondrial DNA suggests the following relationships:

Otters (Aonyx, Enhydra, Hydrictis, Lontra, Lutra, Lutrogale and Pteronura) form a single clade. This clade is the sister to one consisting of the mink and true weasels (Mustela and Neovison).

Another clade that includes the weasel-like species with aposematically colored pelage (Galictis, Ictonyx, Poecilogale and Vormela) is the sister to these first two clades.

A further clade of ferrets and badgers (Melogale) is the sister to these three combined clades.

The fifth major clade has two subclades: the first contains the hog-nosed and Eurasian badgers (Arctonyx and Meles) and a second contains the tayra, wolverine and martens (Eira, Gulo and Martes).

The most divergent groups are two clades consisting of the American badger (Taxidea) and the honey badger (Mellivora).

Mustelidae






Lutrinae


Mustela, Neovison (Subfamily Mustelinae)



Galictis, Vormela, Ictonyx, Poecilogale (Subfamily Galictinae)



Melogale (Subfamily Helictidinae)




Eira, Gulo, Martes (Subfamily Martinae)


Arctonyx, Meles (Subfamily Melinae)




Mellivora (Subfamily Mellivorinae)



Taxidea (Subfamily Taxidiinae)


Potamotherium miocenicum

Fossil Mustelids

Extinct genera of the Mustelidae family include:

References

  1. ↑ "A Skunk By Any Other Name…". Dragoo Institute for the Betterment of Skunks and Skunk Reputations. http://www.dragoo.org/Mephitidae.html. Retrieved 2007-02-26. 
  2. ↑ 2.0 2.1 King, Carolyn (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 108–109. ISBN 0-87196-871-1. 
  3. ↑ Kenyon, Karl W. (1969). The Sea Otter in the Eastern Pacific Ocean. Washington, D.C.: U.S. Bureau of Sport Fisheries and Wildlife. 
  4. ↑ Dragoo and Honeycutt (1997). "Systematics of Mustelid-like Carnvores". Journal of Mammalology 78 (2): 426–443. doi:10.2307/1382896. http://jstor.org/stable/1382896. 
  5. ↑ Thierry Lodé, J. P. Cornier & D. Le Jacques 2001. Decline in endangered species as an indication of anthropic pressures: the case of European mink Mustela lutreola western population. Environmental management 28: 221-227.
  6. ↑ "Mammal Species of the World, Third Edition". http://www.bucknell.edu/msw3/browse.asp?id=14001075. Retrieved 2008-07-31. 
  7. ↑ Koepfli, Klaus-Peter; Deere, K.A.; Slater, G.J.; Begg, C.; Begg, K.; Grassman, L.; Lucherini, M.; Veron, G. et al. (February 2008). "Multigene phylogeny of the Mustelidae: Resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation". BMC Biology 6: 10. doi:10.1186/1741-7007-6-10. PMID 18275614. PMC 2276185. http://www.biomedcentral.com/1741-7007/6/10. 
  • Whitaker, John O. (1980-10-12). The Audubon Society Field Guide to North American Mammals. Alfred A. Knopf. p. 745. ISBN 0394507622.