Steppe polecat

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Steppe polecat
At the Stepnoi Sanctuary

Least Concern  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Genus: Mustela
Species:
M. eversmanii
Binomial name
Mustela eversmanii
(
Lesson
, 1827)
Steppe polecat range

The steppe polecat (Mustela eversmanii), also known as the white or masked polecat, is a species of

Least Concern on the IUCN Red List because of its wide distribution, occurrence in a number of protected areas, and tolerance to some degree of habitat modification.[1]
It is generally of a very light yellowish colour, with dark limbs and a dark mask across the face.[2] Compared to its relative, the European polecat, the steppe polecat is larger in size and has a more powerfully built skull.[3]

The steppe polecat is a nomadic animal which typically only settles in one area until its prey, mainly ground squirrels, are extirpated.[4] It mates from March to May, and generally gives birth to litters of three to six kits, which attain their full growth at the age of two years.[5] It hunts for larger prey than the European polecat, including pikas and marmots.[6]

Evolution

Skull and jaw of the extinct Mustela eversmanii beringianae

The earliest true polecat was Mustela stromeri, which appeared during the late

common ancestor.[7] The steppe polecat likely diverged from the European polecat 1.5 million years ago based on IRBP, though cytochrome b transversions indicate a younger date of 430,000 years.[8] As a species, the steppe polecat represents a more specialised form than the European polecat in the direction of carnivory, being more adapted to preying on larger rodent species; its skull has a stronger dentition, its projections are more strongly developed and its muscles of mastication are more powerful. The steppe polecat's growth rate is also much slower than the European polecat's, as its skull undergoes further development at an age when the European polecat has attained full growth.[3] The species may have once been present in Pleistocene central Alaska.[9]

Taxonomy

As of 2005[update], seven living subspecies are recognized.[10]

Description

Pelt

The steppe polecat is very close to the

Semirechye had a body length of about 775 mm (30.5 in).[18] Overall, specimens exhibiting gigantism are more common than in the European polecat, and occur primarily in western Siberia, where they likely hybridise with Siberian weasels.[19]

The winter fur is soft and tall, with short, dense underfur and long, sparse guard hairs. The fur is generally shorter and not as thick as that of the European polecat. The guard hairs are especially well developed on the lower back, though still sparser than those of the European polecat. Contrary to the former, the steppe polecat's guard hairs never completely cover the underfur. The base colour of the winter fur is very light yellowish or whitish-yellowish. The tips of the guard hairs are blackish-brown or brown, forming a frosting effect over the yellow underfur. This frosting is stronger in the middle and lower back, where the guard hairs are denser and longer. The guard hairs on the upper back, the flanks, between the shoulders and along the upper neck are extremely short, thus being lighter in colour than the posterior region. The head is piebald, with the eye region and the upper side of the nose being covered by a brownish mask. Behind the mask, a white band crosses the head from cheek to cheek. A small brownish area is usually located in front of each ear. The ears are completely white, while the throat is yellowish-white or almost white. Sometimes, the head is entirely white. The lower surface of the neck is dark blackish-brown or brown, while the chest and forelegs are black or blackish-brown. The abdomen is light, yellowish-straw in colour. The groin is the same colour of the forelimbs. The base of the tail is light in colour, while the tip is dark brown. The summer coat is shorter and coarser than the winter fur, and is not as dense and close-fitting, with a more strongly developed ochreous or reddish tone. The head is, overall, darker than in winter, with greater contrast between the dark and white tones.[2]

Distribution and habitat

The steppe polecat occurs from Central and Eastern Europe in the west through southern Russia, northern Georgia, Kazakhstan, Turkmenistan, Uzbekistan, Tajikistan, and Kyrgyzstan to Mongolia and northern and western China.[1] In 2014, it has been recorded at an elevation of 5,050 m (16,570 ft) in Upper Mustang, Annapurna Conservation Area, Nepal.[20]

Behaviour and ecology

Territorial and sheltering behaviours

Pocock
's The Fauna of British India, including Ceylon and Burma - Mammalia Vol 2

The steppe polecat does not hold sharply defined home ranges. During warm seasons, especially in areas rich in ground squirrels, aged polecats hold relatively stable territories until they have extirpated their prey. Younger polecats are less sedentary, and will sleep overnight in the burrows of ground squirrels they have killed. Females nursing their litters are the most settled, but will begin roaming once the kits are old enough to accompany them. Generally, the steppe polecat only occupies one home range for a few days or up to a few months. In winter, the steppe polecat is more active and moves 12–18 km (7.5–11.2 mi) a day. During heavy snowfall, the steppe polecat migrates to more favourable areas, such as along the slopes of steppe ravines, near settlements and winter encampments.[4]

The species does not usually dig its own burrow, instead using those of marmots, ground squirrels, hamsters, moles, voles, jerboas and others, after slightly widening them. Its burrow is often poorly constructed, as it does not inhabit one long enough to warrant restructuring. Nesting burrows are not lined, and have many outlets, ranging from three to 20. Alongside the nest chamber is a food store. Independently dug burrows are typically shallow and simple in construction.[4]

Reproduction and development

In captivity, mating was observed in early March till the end of the month. In the

gestation period lasts from 36–43 days. Placentation occurs two weeks after mating, with the blastocyst stage lasting seven to eight days. Litters usually consist of three to six kits, though litters of 18 are known.[5]

Kits are born blind and naked, with pale rose skin and a membrane over the ears. At birth, they measure 6.5–7 cm (2.6–2.8 in) in length and weigh 4.5 grams (0.16 oz), though polecats born in the Moscow Zoo weighed 10 grams (0.35 oz). Usually, the weight of newborn kits depends on litter size. A thin, white underfur appears on the body after three days, and the body length doubles, while the weight increases six-fold at up to 33 grams (1.2 oz).

Milk teeth erupt around the same time, and the feet begin to darken. On the 20th day, the kits darken in colour and weigh 70–72 grams (2.5–2.5 oz). The eyes open after 28–34 days, and the kits become more active, to the point of attempting to tear apart prey whilst still relying on the mother's milk. At the age of one month, kits measure 190 mm (7.5 in) in length and weigh 138 g (4.9 oz). By the age of 45 days, they are able to hunt young ground squirrels, and begin to target adults at the age of 60 days. The kits remain in the family burrow for 2.0–2.5 months. The kits begin to disperse from July or later, and attain sexual maturity at the age of 10 months. They reach adulthood at the age of two years.[5]

Diet

Unlike the European polecat, which feeds mostly on

willow grouse. Amphibians and reptiles are rarely eaten.[6]

Diseases and parasites

The steppe polecat is weakly susceptible to sylvatic plague,

Helminth infections, as well as tick infestations are widespread in the species. Up to 11 flea species are known to infest the steppe polecat, some of which are picked up from its prey.[21]

Relationships with humans

The steppe polecat is of great

plowing of Virgin Lands and changes in agrochemical methods. The steppe polecat is fairly easy to harvest. It is primarily caught with jaw traps located near inhabited burrows.[22]

References

  1. ^
    doi:10.2305/IUCN.UK.2016-1.RLTS.T29679A45203762.en
    . Retrieved 19 November 2021.
  2. ^ a b c Heptner & Sludskii 2002, pp. 1136–1137
  3. ^ a b Heptner & Sludskii 2002, pp. 1143
  4. ^ a b c Heptner & Sludskii 2002, pp. 1169–1170
  5. ^ a b c Heptner & Sludskii 2002, pp. 1172–1173
  6. ^ a b Heptner & Sludskii 2002, pp. 1166–1167
  7. ^ Kurtén 1968, pp. 98–100
  8. S2CID 33505504. Archived from the original
    (PDF) on 2011-10-03. Retrieved 2011-06-02.
  9. JSTOR 1378982
    .
  10. OCLC 62265494
    .
  11. ^ a b Heptner & Sludskii 2002, pp. 1160–1161
  12. ^ Heptner & Sludskii 2002, pp. 1164–1165
  13. ^ Heptner & Sludskii 2002, pp. 1163–1164
  14. ^ a b Heptner & Sludskii 2002, pp. 1162–1163
  15. ^ Heptner & Sludskii 2002, pp. 1135
  16. ^ Heptner & Sludskii 2002, pp. 1138–1139
  17. hdl:2027/uc2.ark:/13960/t3tt4h07f
    .
  18. ^ Heptner & Sludskii 2002, pp. 1142–1143
  19. ^ Heptner & Sludskii 2002, pp. 1141
  20. ^ Chetri, M.; Odden, M.; McCarthy, T. & Wegge, P. (2014). "First record of Steppe Polecat Mustela eversmanii in Nepal". Small Carnivore Conservation. 51: 79–81.
  21. ^ Heptner & Sludskii 2002, pp. 1173–1174
  22. ^ Heptner & Sludskii 2002, pp. 1175–1176

Bibliography

External links

Wikimedia Commons has media related to Mustela eversmanii.
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