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Mustela subpalmataEgyptian weasel

By Morten Swayne Storgaard

Geographic Range

The range of Mustela subpalmata is restricted to the lower Nile Valley, from Alexandria in the west to Port Said in the east and from the Delta south to Beni Suef. (McDonald and Hoffmann, 2008; Osborn and Helmy, 1980)

Habitat

Egyptian weasels are terrestrial animals mostly found in urban areas living synanthrophic with humans. Only a few specimens have been collected outside cities; mostly on cultivated fields. They are often found in public buildings and houses, where they regularly get trapped in underground food stores. They are considered as common to abundant with densities estimated from trapping ranging from 0.5-1 individuals/ha. (Handwerk, 1993; McDonald, 2014; Osborn and Helmy, 1980)

Physical Description

Egyptian weasels have a distinctive mustelid body shape; long, elongated and slender body with short legs and tail. They are very small carnivores with an average body size, which is measured as head to body length (HBL), of 289 mm in males and 242 mm in females. The average tail lengths for males and females, respectively, are 116mm and 99mm, which are approximately 30-40 % of the body size, whereas the tail in least weasels (Mustela nivalis) is less than 25%. The size of Egyptian weasels is larger than the closely related least weasel. Head sizes also exceed those of the least weasel but are in general small and flattened with a short and broad rostrum. An unusual feature can be found in M. subpalmata and weasels in general; the sagittal, nuchal and lamboidal ridges (crests) are present and pronounced. The zygomatic arch is widely separated (wider than M. nivalis) and is not strongly curved upwards. They also lack the postorbital swelling, which is found in other mustelids in Africa, and the bulla is not fused with parapterygoid. The pinnae of M. subpalmata are small. They walk with a plantigrade posture with 4 whitish digits on each foot. The dental formula of this specific species has not been studied but for the subfamily Mustelinae it is I 3/3,C 1/1,P 3/3,M 1/2=34, where the upper M2 is reduced to a simple form in M. subpalmata. The canine is pronounced and the outer upper incisor is faintly larger than the two other incisors.

The appearance of M. subpalmata is brown dorsally, and the ventral side varies from white to creamy yellowish with an unequal margin between the two sides. The tail is unicolor with a slightly darker tip in comparison to the body and tail. A general weasel characteristic is that they molt twice a year; in spring and in autumn. The Egyptian weasels remain their same brownish color, whereas winter whitening of the fur occurs at higher latitudes in related species such as the least weasel. The Egyptian weasel does not have the same thermoregulatory issues as smaller weasels living in higher latitudes. The mustelid body is small, long and slender, which means a high surface area to volume ratio, resulting in high metabolic requirement but specific metabolic rates have not been measured in M. subpalmata.

Sexual dimorphism is present in Egyptian weasels but not pronounced compared to least weasels. The mean condylobasal length of female Egyptian weasels comprises 90 % of the males. This is an overestimation of what could be expected from a weasel of that size according to existing literature. The average body mass of females is 200 g according to Flower (1932) and in average 209 g according to Handwerk (1993). The average body mass of males is 390 g. M. subpalmata usually has four pairs of nipples. The average baculum (os penis) size of males is 25.90 mm and is described as slender, grooved below with a hooked distal end. (Flower, 1932; Hoath, 2003; King and Powell, 2007; Osborn and Helmy, 1980; Wolzan, 2013; van Zyll de Jong, 1992)

  • Sexual Dimorphism
  • male larger
  • Range mass
    190 to 425 g
    6.70 to 14.98 oz
  • Range length
    341 to 405 mm
    13.43 to 15.94 in

Reproduction

The mating system has not been described in this species but the closely related species M. nivalis has a polyangyndrous mating system, which means that both males and females have multiple copulations with multiple partners. Individuals of M. subpalmata are solitary and territorial. Males, which are larger than females, also have larger territories, usually overlapping several females. The two sexes avoid each other except during the breeding season as the female are subordinate to males most of year. In the breeding season the opposite takes place; females defend themselves vigorously against unwanted males. Egyptian weasels use urine and scats to mark of their territory, which is typical of male carnivores. Females mainly defend their territories against other females. Both sexes defend themselves vigorously and strongly when facing stressful situations. The courtship sound repertoire includes trilling and chattering. After copulation both sexes rest either together or separately and will either continue copulation or find new mates. (King and Powell, 2007; McDonald, 2014)

Breeding occurs around April and August and litters have been recorded in August and December. Mating occurs only when the female weasel has reached full estrus and mating is vigorous, loud and prolonged. Ovulation is induced and an outer physical stimulation is needed. The male baculum (os penis) has a key role in ovulation as ovulation only occurs when the male baculum (os penis) stimulates the female upon copulation. Female M. subpalmata have a gestation period of 4-5 weeks. They build nests in any opening like a crevice in a wall etc. The young of M. subpalmata are called kits and dens with kits found in Egypt have contained between 4-9 kits per litter. Studies of litter size in this species are lacking but in the close relative M. nivalis the average litter size is 5.1 ± 2.3 SD. Depending on food availability they can have 2-3 litters per year. Kits are born helpless and naked. They develop hunting behaviors approximately 10 weeks after birth and soon afterwards become independent juveniles. They reach sexual maturity around 4-8 months after birth. (Baryshnikov, et al., 2003; Handwerk, 1993; Hoath, 2003; King and Powell, 2007; McDonald, 2014)

  • Breeding interval
    Egyptian weasels can have 2-3 litters per year.
  • Breeding season
    April to August
  • Range number of offspring
    4 to 9
  • Average gestation period
    4-5 months
  • Range weaning age
    4 to 7 weeks
  • Average time to independence
    10 weeks
  • Range age at sexual or reproductive maturity (female)
    4 to 8 months
  • Range age at sexual or reproductive maturity (male)
    4 to 8 months

Specific studies regarding parental care have not been done on M. subpalmata but the general mustelid pattern has been well described. The male weasel does not contribute to parental care after copulation. All parental care is given by the female weasel. Maternal care includes huddling (kits are born naked) and lactation over 4-7 weeks. (King and Powell, 2007)

Lifespan/Longevity

M. subpalmata does not usually live longer than 1 year. (McDonald, 2014; Sheffield and King, 1994)

  • Range lifespan
    Status: wild
    1 (high) years

Behavior

Egyptian weasels are commensal with humans. They are solitary and highly territorial. The larger male territories can overlap with several female territories. The boundaries of territories are marked by scent from faeces, urine and a scent producing gland. A general mustelid character is that subordinate males and females avoid encounters with larger, dominant males. The only exception is during the breeding season when males seek for mates. They are mainly nocturnal but can be seen during the day. A typical interaction with humans is running across the street at night and hiding underneath nearby parked cars. (Hoath, 2003; King and Powell, 2007; McDonald, 2014; Osborn and Helmy, 1980)

Home Range

The home range and territory size of M. subpalmata are not known.

Communication and Perception

Mustela subpalmata relies on several senses in hunting and perceiving the environment. They have good sight and hearing; the main sense used in hunting rodents is olfaction. They have a sharp, barking alarm call. A general mustelid characteristic is that they communicate via scent. Scent is used to communicate between neighboring weasels and to advertise territories. The scent producing gland used to mark territories is located along the dorsoventral and ventral sides of the body. When marking territories they rub their body on the ground releasing a substance. Other substances such as scats and urine are also used in mark routes. The use of scents to communicate with other weasels and how they perceive these scents has not been studied in M. subpalmata. In another closely related species, the stoat or the short-tailed weasel (Mustela erminea), dominant individuals show no obvious reaction when encountering the scent of a subordinate weasel but if a subordinate detects the scent of a dominate individual they show signs of anxiety. Subordinates will then look for escape routes while simultaneously calling out trilling calls that imitate the sound of young weasels, to mitigate the response of the dominant weasel. (King and Powell, 2007; Stubbe, 1970)

Food Habits

Mustela subpalmata is an opportunistic feeder; for example they scavenge at restaurants and eat insects, fish etc. in major cities. Contrary to their European relatives, rodents do not apparently play a big part in their diet. The diet is unusual for a weasel as it contains a high percentage of fruit and vegetables (≈50%), including grapes, dates, wheat (bread) and beans. This diet emphasizes the opportunistic lifestyle of this species; living in an urban space with a lot of markets and food stores. Their diet does include some small mammals (rats, house mice (Mus musculus) and the common rabbit (Oryctolagus cuniculus) (2%)), chicks and ducklings (23%), fish leftovers (1%) and insects such as cockroaches (11%). In addition they will scavenge in trash bins and waste heaps. (Handwerk, 1993; Hoath, 2003; King and Powell, 2007; Osborn and Helmy, 1980)

  • Animal Foods
  • birds
  • mammals
  • fish
  • carrion
  • insects
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

Predation

Data available for this particular species are lacking but some of the predators of closely related species likely prey on Egyptian weasels. Possible predators include raptors, crows feral and domestic cats (Felis catus) and dogs (Canis lupus familiaris), foxes and large owls (Strigidae). (Hellstedt and Kallio, 2005; King and Powell, 2007; McDonald, 2014)

Ecosystem Roles

A disease of concern in Egypt, schistosomiasis, is caused by trematodes such as Schistosoma mansoni and S. heamatobium. Mustela subpalmata is not a good host of these trematodes; the susceptibility is poor. Mustela subpalmata is commensal with humans mainly in the larger cities in Egypt. They may regulate rodent populations but their role in rodent population dynamics has not been studied. The closely related M. nivalis plays a vital role in regulating lemmings in the tundra. (Feige, et al., 2012; Kuntz and Malakitis, 1955)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

The Egyptian weasel consumes a substantial amount of fruits and berries (≈50%) but it also hunts pest rodents living in inhabited areas. (Handwerk, 1993)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Mustela subpalmata lives in closely association with humans and prey upon domestic livestock such as chicken and hens, as well as eating fruit from markets. (Handwerk, 1993; McDonald, 2014)

  • Negative Impacts
  • household pest

Conservation Status

Although M. subpalmata is found in a restricted geographic range, it is still considered as the category of Least Concern on the IUCN. The species lives commensalistic with humans where it is common and considered adaptable. The species has currently no known threats. (McDonald and Hoffmann, 2008)

Other Comments

The population of weasels in Egypt is considered as a post-glacial relict of more widely distributed populations that occurred north and east into Israel, as fossils found in Shaar Ha'amaqim reveal. Until recently the Egyptian weasel was considered to be a subspecies of the least weasel, and was named Mustela nivalis subpalmata. It has been treated as its own species Mustela subpalmata in the literature since 2000 and was given species status by Wozencraft (2005). This new taxonomy is based on its unique cranial morphology, larger body size, and lower degree of sexual dimorphism. The population in Egypt has been isolated from Mustela nivalis in Europe since the last glacial period. (Abramov and Baryshnikov, 2000; Bar-Oz, et al., 2000; Reig, 1997; Wozenkraft, 2005; van Zyll de Jong, 1992)

Contributors

Morten Swayne Storgaard (author), University of Manitoba, Jane Waterman (editor), University of Manitoba.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

induced ovulation

ovulation is stimulated by the act of copulation (does not occur spontaneously)

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

References

Abramov, A., G. Baryshnikov. 2000. Geographic variation and intraspecific taxonomy of weasel Mustela nivalis (Carnivora, Mustelidae). Zoosystematica Rossica, 8: 365-402.

Bar-Oz, G., A. Segal, T. Dayan. 2000. Weasels (Mustela nivalis) from the Hellenistic well at Shaar-Ha'amaqim. Israel Journal of Zoology, 46,2: 157.

Baryshnikov, G., O. Bininda-Edmonds, A. Abramov. 2003. Morphological Variability and Evolution of the Baculum (os penis) in Mustelidae (Carnivora). Journal of Mammalogy, 84 (2): 673-690.

Feige, N., D. Ehrich, I. Popov, S. Broekhuizen. 2012. Monitoring Least Weasels after a Winter Peak of Lemmings in Taimyr: Body Condition, Diet and Habitat Use. Arctic, 65: 273-282.

Flower, S. 1932. Notes on the recent mammals of Egypt, with a list of the species recorded from that kingdom. Proc. Zool. Soc., London, 1932: 368-450.

Handwerk, J. 1993. Zur Biologie und Ökologie ägyptischer Wiesel, Mustela subpalmata Hemprich und Ehrenberg, 1833.. Zoology in the Middle East, 9: 5-30.

Hellstedt, P., E. Kallio. 2005. Survival and behaviour of captive-born weasels (Mustela nivalis nivalis) released in nature. J. Zool., Lond., 266: 37-44.

Hoath, R. 2003. A Field Guide to the Mammals of Egypt. Cairo, Egypt: The American University in Cairo Press.

King, C., R. Powell. 2007. The Natural History of Weasels and Stoats: Ecology, Behavior and Management. Oxford, U.K.: Oxford University Press.

Kuntz, R., G. Malakitis. 1955. Susceptibility Studies in Schistosomiasis. IV. Susceptibility of Wild Mammals to Infection by Schistosoma haematobium in Egypt, with Emphasis on Rodents. Journal of Parasitology, 41, 5: 467-475.

McDonald, R. 2014. Mustela nivalis/Mustela subpalmata. Pp. 85-87 in J Kingdon, M Hoffmann, eds. The Mammals of Africa. Amsterdam, The Netherlands: Academic Press.

McDonald, R., H. Hoffmann. 2008. "Mustela subpalmata" (On-line). The IUCN Red List of Threatened Species. Accessed October 27, 2014 at http://www.iucnredlist.org/details/41660/0.

Osborn, D., I. Helmy. 1980. The contemporary land mammals of Egypt (including Sinai). Field. Zool. New Ser., 5: 1-579.

Reig, S. 1997. Biogeographic and evolutionary implications of size variation in North American least weasels (Mustela nivalis). Canadian Journal of Zoology, 75, 12: 2036-2049.

Sheffield, J., C. King. 1994. Mustela nivalis Mammalian Species. The American Society of Mammalogists, 454: 1-10.

Stubbe, M. 1970. [On the evolution of anal marking organs of Mustelids]. Biologisches Zentralblatt, 80: 212-223.

Wolzan, M. 2013. Mustelinae - Weasels, Polecats. Pp. 84 in J Kingdon, M Hofmann, eds. The Mammals of Africa. Amsterdam, The Netherlands: Academic Press.

Wozenkraft, W. 2005. Order Carnivora. Pp. 532-628 in D Wilson, D Reeder, eds. Mammal Species of the World: A taxonomic and geographic reference, Vol. 3. Washington, DC, USA: Smithsonian Institution Press.

van Zyll de Jong, C. 1992. A morphometric analysis of cranial variation in Holarctic weasels (Mustela nivalis). Z. Saeugetierkd., 57: 77-93.

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