#1 Beech Marten (Martes foina)

The beech marten, also known as the stone marten, house marten, or white breasted marten, is native to much of Europe and Central Asia, though they have been brought to North America where they have established a feral population in the US state of Wisconsin. Unlike most mustelids, the beech marten thrives in and around human settlements; both in cities and more rural areas.

Appearance

The beech marten is often confused for the Eurasian pine marten, but is very different by closer inspection. A heavier body with much shorter limbs make them appear less athletic, ironically with a tail that is longer than that of the woodland dwellers they are compared to. In terms of little details, the ears are smaller, the eyes larger, the nose pinkish brown rather than dark, and the paw pads are bared. The fur has no value whatsoever, being coarse with sparsely spread guard hairs. This exposes the greyish-white undercoat, which is why the overall colour appears light brown. Tail, limbs, and underside is dark brown, in stark contrast to the white bib that characteristically splits between and spreads down the front limbs.

Habitat

They are uniquely tolerant of urban and open areas compared to other marten species. In natural areas they may be found not only in dense forest, but also rocky hillsides, outcrops, cliffsides, shrubland, and on mountain peaks up to 4200m in elevation.⁽¹⁾ They prefer topographically complex environments that provide secure denning sites, usually in the form of rock crevices, hollow trees, or abandoned animal burrows.⁽²⁾ As such, forest-dwelling beech martens prefer old-growth temperate forests, particularly hilly oak groves, but may rarely be found in middle-aged mixed forest. They will avoid areas with deep snow, due to having double the weight load on their paws as Eurasian pine martens.⁽³⁾

Urban-dwelling beech martens have a strong reliance on human-built structures, often making their dens in the attics of buildings. They prefer buildings uninhabited by humans, but are more willing to den in inhabited (and thus heated) dwellings in winter. Garages, warehouses, sheds, ruined homes, and other areas of lower human traffic are also attractive to beech martens. Dens may rarely be found outside in culverts, wood piles, brambles, thickets, and even cars. Barns are an attractive choice for rural martens, presumably due to an abundance of hay and other nesting materials.⁽⁴⁾⁽⁵⁾

Introduction to the US state of Wisconsin

The beech marten is found in Wisconsin, particularly near urban areas of Milwaukee. They can also be found in the Kettle Moraine State Forest, as well as neighbouring woodlands in Walworth, Racine, Waukesha, and maybe Jefferson Counties. They most likely descended from feral animals that escaped from a private fur farm in Burlington around the 1940s.⁽⁶⁾ They have also been reported to have been released or having escaped in about 1972.⁽⁷⁾

Behaviour

Beech martens are primarily nocturnal, especially in urban populations which take advantage of reduced human activity. They are generally solitary and highly territorial toward individuals of the same sex, but may share territory and dens with individuals of the opposite sex. Territory of natural-dwelling male martens ranges from 12 to 211 hectares; research of urban-dwelling martens is limited, but one study recorded a maximum territory of 135.8 hectares (335 acres) out of 13 tracked individuals. Males generally have a larger territory than females. Both sexes communicate primarily through scent, especially through urine marking.^(2)(4)(5)

Individuals will rarely venture outside of the type of habitat they were raised in; urban martens will stay urban, and rural or natural-dwelling martens will stay within their familiar territory. They will avoid humans regardless of their environment.⁽⁴⁾

Reproduction

M. foina breeds from June to August. Females are initially aggressive towards males, and the male will make a cooing vocalisation to soothe the female until she becomes receptive. The male will then scruff the female with his teeth to immobilise her, before mating for up to an hour. M. foina is considered promiscuous, with both males and females mating with multiple partners when able.

Females exhibits delayed implantation, with embryos not attaching to the uterus until the February following mating. Development lasts about one month, with females giving birth to 2-7 (average 3) altricial kits. The young open their eyes at 30-36 days old and are weaned in May immediately before mating season. They reach full size in July and are independent from their mother by summer’s end. Sexual maturity is reached at 15-27 months. Males are not known to assist in rearing young.⁽²⁾⁽³⁾

Urban-dwelling martens have a lower reproductive rate than wild-dwelling martens.⁽⁴⁾

Diet

Beech martens are omnivorous like other martens, but are distinguished by a higher degree of frugivory. They are appear to be particularly fond of cherries, apples, pears, and yew fruit where available. Other typical fare includes rodents, hares, insects, earthworms, small birds, and eggs, any or all of which may constitute a significant portion of an individual marten’s diet. They may also eat lizards, frogs, mollusks, vegetables, seeds, and honey (it has been reported that beech martens are immune to bee and wasp stings, but more research is needed). Carrion is generally avoided but may be consumed if necessary.^(2)(3)(4)

Urban martens tend to have a greater preference for birds (especially pigeons) than their wild-dwelling counterparts, who have a greater preference for small mammals. Insects, particularly caterpillars, may also make up a larger part of the urban marten’s diet. They will occasionally scavenge pet food from bowls left outside, but generally prefer live animal prey or fresh plant-based foods. Like wild-dwelling martens, urban martens generally avoid carrion and garbage unless necessary, but have been known to consume rubber or plastic items, or aluminium foil (it is unknown if they recognise these items have no nutritional or caloric value).⁽⁴⁾

Individuals have been known to target chicken coops and rabbit hutches, and will cache surplus prey for later consumption if possible.⁽²⁾ There have been cases of beech martens killing European polecats.⁽³⁾

Predators

Beech martens are fairly resistant to predation, but may be taken by larger predators such as foxes and eagle owls. Eurasian pine martens are competitors and may kill subadult beech martens. Wild and domestic cats are “rivals” of the beech marten and they may attack each other, to varying outcomes.⁽²⁾⁽³⁾

Damage to automobiles

Beech martens have become notorious across many European cities where local populations have developed a habit of chewing on car parts, damaging or disabling vehicles and necessitating costly repairs. This behaviour is not yet entirely understood, but research suggests there are two aspects to the issue: what initially attracts Martes foina to a vehicle, and what motivates them to stimulate the local auto repair industry. To confound the issue, not every urban beech marten population shows this sort of interest in automobiles, and among populations that do, some have only more recently exhibited this behaviour than others, suggesting this behaviour is learned – passed down from mother marten to child marten.

Although martens occasionally use vehicles to take quick rests or cache food, the beech marten’s territoriality is likely the largest motivator for their interest in automobiles. Damage reports of this nature peak in spring and summer (birthing and breeding season for Martes foina, when the species is most territorial) and lessen in autumn and winter. As vehicles are driven and parked in various areas throughout a city they may pass through the territory of multiple martens. In populations where this learned behaviour is common, the vehicle may be scent-marked (usually with urine) by several male or female martens. As the vehicle returns to its usual overnight parking spot, the local marten of that area will be attracted to the intruding scent of foreign martens, and compelled to apply their own scent. The cycle will continue as the car is driven about the next day, bearing with it the scent of many martens. However, this does not explain the chewing behaviour. Biologist Jan Herr, who tracked a vehicle and its marten visitors as part of his 2008 Ph.D thesis on urban beech martens, writes:

“The car used for radio tracking was repeatedly visited and marked by several martens, male and female, throughout the study towns. Also, when not in use for radio tracking it was parked at night in a different town where the presence of martens had also been confirmed. Thus, even though this car clearly carried the scent of strange martens it apparently did not trigger aggressive biting as it was never damaged during the two-year study period. Also, visual observations of martens marking or over-marking outside the engine compartment did not show any behaviour resembling aggressive biting.” Ecology and Behaviour of Urban Stone Martens (Martes foina) in Luxembourg pp. 86-87.

Although other explanations have been offered, from an attraction to the scent of a warm engine to simple play or curiosity, the direct cause for marten damage in automobiles is still unknown.⁽⁴⁾

How to humanely marten-proof automobiles

Try blocks of WC-cleaner, dog hairs, or anything that has a strong smell or taste. You can also use devices that send out ultrasonic sounds (preferably those that change sound, so the marten does not become desensitised). Having an electric device installed in the engine compartment that puts out a weak shock is another option.⁽⁸⁾ This should be done by a professional.

In media

Perhaps the most famous beech marten in media is one that dashed about a football field during a 2013 Swiss League match. A Swiss player gave chase and caught the marten with his bare hands—receiving a proper bite on the finger in return. Unfortunately, nearly every media outlet misleadingly claimed that the animal was a pine marten.^{(9)(10)(11)(12)} This is yet another example of how this broadly applied common name can cause confusion and spread viral misinformation about another species.

Body length: 43–59 cm / 17–23 in (males),  38–40 cm / 15–16 in (females)
Tail length: 25–32 cm / 10–12.5 in (males), 23–27.5 cm / 9–11 in (females)
Weight: 1.7–2.1 kg / 4–4.5 lb (males), 1.1–1.5 kg / 2.5–3 lb (females)
Lifespan: Up to 10 years (wild), up to 18 years (captivity)
Range: Most of Europe and central Asia, introduced to the US state of Wisconsin.
Conservation status: Least concern
Subfamily: Guloninae
Recognised subspecies⁽¹³⁾

References

#2 Eurasian Pine Marten (Martes martes)

The Eurasian pine marten, also known as the European pine marten, or simply pine marten, is native to much of Europe and parts of West Asia. Despite usually having the word “pine” in their common names they are not partial to pine trees.

They are less commonly known as the baum marten or sweet marten—the latter name in reference to the belief that their scent glands produce a less offensive odour than that of the European polecat.⁽¹⁾

Appearance

A balanced marten without extremes—everything about them seems to be proportionally moderate. They can be told apart from the other small martens by their more boxy muzzle and narrower zygomatic arches (cheek bones), as well as their longer limbs. Their fur is usually dark chocolate brown, varying in depth between individuals. The bib (throat patch) is cream to light yellow in colour, varies in size and shape between subspecies, and the number of  spots is used to identify individual martens. The ear brims is also cream to light yellow, framing the dark-and light-tipped fur inside.

The Eurasian pine marten is often confused with the North American marten. By comparison, the North American marten has a proportionally larger and wider head, with more pronounced zygomatic arches (cheek bones), a more slender muzzle and shorter limbs. The fur is medium to light brown and warm in tone, with darker paws and tail and a slightly lighter face. A bib (throat patch) is present, varying in size between individuals and yellow to apricot in colour. The North American marten’s winter coat is longer, denser, and silkier. Contrasts are much more pronounced, often with the face appearing almost white.

Winter coat

Light warm brown in colour, long, very dense and silky. The limbs, paws and underside remain dark, while the bib (throat patch) remains light yellow.

Habitat

The Eurasian pine marten lives primarily in coniferous, deciduous and mixed forests. Despite the name, pine trees are neither essential or necessary for this marten to thrive. The ideal living space is old-growth forests with a variety of coniferous and leaf-bearing trees that have been allowed to grow and decay naturally without disturbance. Old trees provide both food, protection and dens for a great number of species, but also rocks, crags and boulders play a vital role for many of the same reasons. In areas with few predators or competitors they may be found in any habitat, even grasslands with no tree cover.⁽²⁾

Behaviour

Like other martens they are semi-arboreal and adept tree climbers, able to travel as swiftly and hunt as effectively in trees as on ground. They usually den in hollow trees but may also be found in abandoned squirrel or bird nests, or—especially in winter—underground. They are solitary and mainly nocturnal.

Males may command a territory over 20 km² in area and females around 6.5 km². Territory is scent marked with scat deposits. Both sexes are territorial, but adults may tolerate newly independent subadults passing through. Some adults become increasingly territorial in winter, a behaviour hypothesised to push out aforementioned subadults that have lingered too long to free up space for the coming mating season’s litters.⁽¹⁾ Once settled into a territory, a marten will rarely migrate away.⁽³⁾

Unlike the oft-confused beech marten, the Eurasian pine marten is not known to live in human settlements.⁽²⁾

Reproduction

Mating season for Martes martes is July-August. Females exhibit delayed implantation, with implantation occurring February-March. Gestation lasts about a month and parturition occurs March-April. Litter size ranges from two to eight, average three. Young are altricial. Eyes open 34-38 days from birth, weaning occurs at six weeks from birth, and young emerge from the den at seven to eight weeks after birth.

Young usually disperse to find their own territory around 12-16 weeks old, but some may overwinter in their maternal den and disperse in the following spring. First mating may occur around 14 months old but more often is delayed until the second or third year.⁽²⁾⁽³⁾

Diet

Being a omnivore means not being picky and eating whatever is available throughout the seasonal cycle, in addition to hunting prey. The menu consists of small rodents, lagomorphs, birds, carrion, eggs, fish, insects, amphibians, earthworms, mushrooms, and a surprisingly large amount of vegetable matter- during autumn fruit, nuts and berries can make up to 85% of the diet! The Eurasian pine marten’s sweet tooth is well documented by trappers and photographers, who make use of bait in the form of raisins, honey, ficus or jam to lure the otherwise elusive animals out of their safe hiding places, and there have even been a report of a marten going crazy for cake in a ski-slope restaurant.⁽⁴⁾ It can be fascinating to learn that omnivores can have unexpected quirks, and for people who wish to interact with martens it is a neat trick to know. Feeding stations are becoming popular in this regard, though it is recommended to be careful with processed and sugary foods and use healthier and more natural alternatives.

Enemy and ally of squirrels

In areas where the invasive eastern grey squirrel (Sciurus carolinensis) threatens the native red squirrel (Sciurus vulgaris) population, the reintroduction of Eurasian pine martens has been somewhat effective in culling the invasive competitors and allowing the red squirrel to recover. The red squirrel—having evolved alongside the Eurasian pine marten over a millennia—is more resistant to predation by the marten than the grey squirrel, which has no such history and thus easily falls prey. In some areas the reintroduction of the Eurasian pine marten has reduced the grey squirrel population below detectable levels.⁽⁵⁾

However, the reintroduction of Eurasian pine martens may not be a long-term solution to the problem. Given the lack of forest cover in Ireland and Britain for the marten to thrive, and the fact that they often avoid human populations, grey squirrels could continue to thrive in urban and suburban areas.⁽⁶⁾

Predators

Adults are generally resistant to predation but may fall prey to wolverines, red foxes, eagles, and other birds of prey.⁽³⁾

Body length: 53 cm / 21 in
Tail length: 25 cm /10 in
Weight: 0.5–1.7 kg / 3.3–3.7 lb
Lifespan: Up to 10 years (wild), up to 17 years (captivity)
Range: Most of Europe, Asia Minor, northern Iraq and Iran, the Caucasus, and in westernmost parts of Russia.
Conservation status: Least concern
Subfamily: Guloninae
Recognised subspecies⁽⁷⁾

References

#3 Japanese Marten (Martes melampus)

The Japanese marten (Hondoten being their Japanese romanised name) is found on the islands of Honshu, Shikoku, and Kyushu in Japan. In 1949, the species was introduced to the Sado and Hokkaido Islands to increase fur products.⁽¹⁾  The Japanese marten’s closest relative is the sable, and they both share a similar habitat in Japan.⁽²⁾

Appearance

When searching for photographs of a Japanese marten, often the majority of the results will be of them in their winter coat. Their summer coat is so dissimilar that one could be astonished to learn they are the same species. The summer coat is medium to light brown in colour, with dark brown to blackish on the lower part of the limbs, and a similar coloured mask that partially to completely covers the face. They can also sometimes have white or cream coloured tail-tips.

Winter coat

The winter coat is denser and a dull yellow, with the head being completely or partially white in colour. The paws sometimes remain a medium brown to blackish while in this coat.^(3)(4)(5)

They are sometimes confused with the Malay weasel while in their winter coat, because of their similar white-furred face. However, being a species of marten, they are distinctively larger and bulkier than the Malay weasel. Their nose is also typically black rather than pink, and the limbs are dark brown to blackish instead of being the same colour as the body like on the Malay weasel.

Habitat

The Japanese marten is found along the valleys and boreal forests of much of Japan’s mainland.⁽⁶⁾

Behaviour

Japanese martens are reported to be generally nocturnal but with great variation among individuals. They spend over 60% of their time asleep.⁽⁷⁾ Dens are made in trees and ground burrows. Territories of both sexes average less than 1 km² in area and are marked with scat deposits.⁽⁸⁾

One study published in the Mammal Society of Japan’s journal Mammal Study states Japanese martens may invade human residences and cause problems à la the Eurasian pine marten; however there are no readily-accessible studies or local news sources confirming the prevalence or existence of this issue.⁽⁹⁾

Reproduction

Mating season for M. melampus occurs July-August and parturition occurs April-May.⁽¹⁰⁾ Litter size ranges from one to five altricial kits. Young become capable hunters by three to four months old and become independent shortly after.⁽⁸⁾

Male Japanese martens have a relatively large penis and may become stuck inside a female if startled while mating. This is an uncommon example of a copulatory tie in a non-canid species, albeit an “accidental” tie rather than an “intentional” one.⁽¹¹⁾

Diet

The diet of Japanese martens varies by season. They are known to consume fruits and berries from spring to autumn, insects in summer and autumn, and small mammals and birds all year round. They have been reported to eat seeds, rabbits, birds, bird eggs, invertebrates, centipedes, spiders, frogs, fish and crustaceans.⁽⁴⁾ They appear to be capable of ransacking mature wasp nests and carrying away combs.⁽¹²⁾

Predators

Little data is available on predators of the Japanese marten. They may be vulnerable to attack by feral or stray dogs.⁽⁸⁾

Environmental benefits

Japanese martens play an important role in seed dispersal. Due to their consumption of fruit and seeds, and large home ranges, they are great dispersal vectors in northern climates of Japan where seed dispersal is low.⁽¹³⁾

Threats and conservation efforts

Due to the logging industry, Japanese martens are decreasing in numbers and struggling to rebound in some areas that were previously well-forested. Insularization occurs in some populations, causing changes in foraging and decreasing the genetic pool.⁽¹⁾ Excessive trapping for its fur and agricultural insecticides have also contributed to their decreasing numbers.⁽³⁾

In 1971, the Japanese marten was named a Natural Monument Species by the Japanese Agency of Cultural Affairs. Since this declaration, steps have been taken to conserve the species—regulations being put in place to protect female Japanese martens from trapping.⁽³⁾ Japanese martens also have legal protection on the Tsushima Islands.⁽¹⁴⁾

Body length: 47–54.5 cm / 18.5–21.5 in
Tail length: 17–22.3 cm / 7–9 in
Weight: 0.5–1.7 kg / 1.0–3.7 lb
Lifespan: Unknown (wild), up to 12 years (captivity)
Range: Much of Japan’s mainland.
Conservation status: Least concern
Subfamily: Guloninae
Recognised subspecies⁽¹⁵⁾

References

#4 Nilgiri Marten (Martes gwatkinsii)

The Nilgiri marten is endemic to the hills of the Nilgiris and parts of the Western Ghats of Southern India.⁽¹⁾

Appearance

The Nilgiri marten’s coat colour is deep brown from head to tail, with a yellow to orange throat patch. They look similar in appearance to the yellow-throated marten, but are distinguished by their flatter skull structure with prominent frontal concavity and baculum shape.⁽¹⁾ The fur on the Nilgiri marten’s back is usually dark brown in colour compared to the yellow-throated marten’s more common yellow or lighter brown. They also differ in that, unlike the Nilgiri marten, the yellow-throated marten typically has yellow fur that runs from the neck to as far back as the hips.

Habitat

They tend to live in moist tropical rainforests of southern India, preferring altitudes of 300 to 1,200 metres (984 to 3,937 feet). They may also be found in coffee and cardamom plantations.⁽²⁾

Behaviour

Little is known about the Nilgiri marten, but it is assumed to be generally similar to the yellow-throated marten. It is mainly diurnal and is an adept climber of trees, capable of travelling long distances through a dense forest canopy.⁽³⁾ They are elusive creatures and are usually seen alone or in pairs when seen at all.⁽⁴⁾ Given their close relation to the yellow-throated marten it is possible this species may also hunt in groups.

Young Nilgiri martens may communicate with their parents through vocalizations. As mustelids it is likely scent plays a major role in communication. The species maintains latrine sites to deposit waste.⁽⁵⁾

Reproduction

There is no available information on reproduction in M. gwatkinsii.

Diet

The Nilgiri marten has an omnivorous diet typical of marten species. They are known to prey on chevrotains, monitor lizards, crows, tree squirrels, and cicadas. They may consume fruits and seeds, and may raid commercial beehives for honey.^(1)(2)(3)(5)

Predators

There is no available information on predators of M. gwatkinsii. The species is threatened by habitat destruction and poaching, sometimes in retribution for beehive raids.⁽²⁾⁽⁶⁾

Body length: 55–65 cm / 22–26 in
Tail length: 40–45 cm / 16–18 in
Weight: 2.1 kg / 4.6 lb
Lifespan: Unknown (wild), up to 14 years (captivity)
Range: Travancore Kerala, Nilgiris, Kodagu north up to the Charmadi ghats, Karnataka.
Conservation status: Vulnerable
Subfamily: Guloninae
References

#5 North American Marten (Martes americana) and #6 Pacific Marten (Martes caurina)

The North American marten, also known as the North American pine marten, or more commonly referred to as the American marten or simply pine marten, is found throughout northern North America.

The Pacific marten is found in western North America, coastal islands of Vancouver, Queen Charlotte, Admiralty, and Kuiu. They were formally considered conspecific with the North American marten, but molecular investigations now support they are both distinct species from one another.⁽¹⁾

Since there is little literature dealing with the Pacific marten as a separate entity from the North American marten, and the two species are presumably functionally identical in biology, habits, and ecology, they will be considered together in this overview.

Appearance

While the two species look similar, there are a few differences to point out between them and other similar-looking mustelids.

North American marten

Yet another species that is often mixed up with the Eurasian pine marten. By comparison, the North American marten has a proportionally larger and wider head, with more pronounced zygomatic arches (cheek bones), a more slender muzzle and shorter limbs. The fur is medium to light brown and warm in tone, with darker paws and tail and a slightly lighter face. A bib (throat patch) is present, varying in size between individuals and yellow to apricot in colour. The North American marten’s winter coat is longer, denser, and silkier. Contrasts are much more pronounced, with the face appearing almost white.

The North American marten may also be distinguished from the often confused fisher by its significantly smaller size, proportionately larger ears, and more yellowed throat markings—the fisher’s markings being pure white, when present at all.⁽²⁾

Although numerous publications and laypeople characterise the North American marten as “about the size of a small house cat”, this comparison is misleading. Domestic cats—averaging around 4.5 kilograms (10 pounds)—are substantially larger. Female North American martens weight between 590 and 771 grams (1.3 and 1.7 pounds), similar to Eastern grey squirrels (Sciurus carolinensis) that weigh between 454 and 680 grams (1 and 1.5 pounds).⁽³⁾

Pacific marten

The similarities with the North American marten are many and so striking that even the most detail-oriented of us have trouble telling them apart. A close comparison of the skulls reveals that the Pacific marten may have a broader and flatter head overall, which is the most noticeable in the zygomatic arches.⁽⁴⁾

Habitat

The North American marten lives in coniferous and mixed conifer/deciduous forests, particularly old-growth forests that provide a high degree of structural complexity in the form of fallen logs, hollow trees, and other woody debris that make suitable denning and hunting sites. They may be found at any elevation where suitable habitat exists.⁽⁵⁾ Distribution maps of the North American marten generally align with areas known to regularly remain snow-covered from November-December through March-April, and with average annual maximum snow depths of at least 30 centimetres.^(6)(7)(8)

Behaviour

They display immense behavioural diversity depending on a number of factors. Broadly, they are semi-arboreal, solitary, active throughout the year, establish dens in cavities, and travel primarily on the forest floor. They may be active during any part of the day or night, possibly depending on the active periods of their preferred prey. They are more active in summer than in winter, and may enter torpor to conserve heat and energy during winter.⁽⁹⁾

The North American marten exhibits aggressive territorial behaviour against individuals of the same sex, with older individuals often harbouring many scars on the head and shoulders. Like most mustelids they possess anal scent glands, which are used to mark territory by dragging or shaking the rear or abdomen across the ground or tree trunks. Home ranges average 2.3 km² for females, and 8.1 km² for males. They will avoid openings and clearings when exploring, but may be observed anywhere there is sufficient cover—even beneath the snow in winter, where they dig tunnels to hunt, forage, and rest.^(5)(10)

Reproduction

Breeding season for M. americana occurs between June and September depending on location and photoperiod, and lasts 24 to 46 days. Courtship may last up to 15 days, and involves playing, wrestling, and clucking vocalisations. When mating, the male will immobilise the female by firmly grasping the scruff of her neck with his teeth. Mating may last as long as an hour and a half, and may occur two or three times per day between a single pair. Individuals of either sex may have multiple partners.

Like many mustelids, female North American martens exhibit delayed implantation. The fertilised egg does not attach to the uterine lining to start development until February, with parturition happening 28 days later. One to five kits (three, on average) are born 220-275 after conception, into a tree cavity den lined with dried plant matter as bedding. The kits are altricial but develop quickly, with eyes opening at 39 days old, weaning occurring after 42 days, and full size being reached around 3.5 months of age.

Females reach sexual maturity in their first or second year, and males in their second year. Captive females have successfully bred to 15 years of age. Male North American martens are not currently known to assist in raising young, but more research is needed.^(5)(9)(10)

Diet

North American martens have a varied seasonal diet of small mammals, birds, eggs, amphibians, reptiles, fish, crustaceans, fruit, nuts, insects, earthworms, and carrion, with small rodents being the primary prey.^(2)(10) They have been reported to sometimes prey on the long-tailed weasel.⁽¹¹⁾

Predators

They are vulnerable to predation by horned owls, eagles, coyotes, red foxes, lynx, bobcats, cougars, and fishers.^(9)(10)

Threats to the Humboldt marten

The Humboldt marten, also known as the coastal marten (Martes caurina humboldtensis), is an endangered subspecies of the Pacific marten that was once common in northern California and southern Oregon. They were thought to be extinct until being rediscovered in the Six Rivers National Forest in 1996.⁽¹²⁾

Habitat loss, legal trapping, and vehicular fatalities have contributed to the decline of the Humboldt marten’s numbers.⁽¹³⁾ In 2020, the U.S. Fish and Wildlife Service announced that the Humboldt marten will receive protection as a threatened species under the Endangered Species Act.⁽¹⁴⁾

North American marten statistics

Body length: 36–45 cm / 13–17 in
Tail length: 13.5–16 cm / 5.4–6.4 in
Weight: 0.5–1.4 kg / 1.1–3.1 lb
Lifespan: Unknown (wild), up to 17 years (captivity)
Range: Much of northern North America.
Conservation status: Least concern
Subfamily: Guloninae
Recognised subspecies^(15)(16)

Pacific marten statistics

Body length: 48–65 cm / 19–25 in
Weight: 1.8 kg / 4 lb
Lifespan: Unknown (wild), unknown (captivity)
Range: Western United States, coastal islands of Vancouver, Queen Charlotte, Admiralty, and Kuiu.
Conservation status: Apparently secure (According to NatureServe)
Subfamily: Guloninae
Recognised subspecies⁽⁹⁾

References

#7 Sable (Martes zibellina)

The sable (not to be confused with a sable ferret, which refers to the most common fur colour of the ferret) inhabits parts of Northeast Europe and much of North Asia. They are the only members of genus Martes that do not have “marten” in their English common name. In regions where both the sable and the Eurasian pine marten occur, interbreeding gives birth to hybrids known as “kiduses”⁽¹⁾ or “kidases”.

Appearance

Sables have a slender muzzle, a wide head with pronounced zygomatic arches (cheek bones), the proportionally largest ears of all mustelids and a short tail compared to the other martens. It is easy to think of the sable as a chubby, fur-bearing animal given their use in the fur industry and the cold climate of their habitat. This is due to their thick winter coat, which can alter their actual shapes dramatically: in summer, the legs seem to elongate, and they appear almost comical with their slender bodies in contrast to their large heads, ears, and paws.

Wild-type sable fur can range from light brown (or sandy-yellow) to almost black. Many individuals have a lighter and grey-tinted head with a characteristic bib (throat patch) that is reduced to a small blotch that ranges from light yellow to apricot and ochre in colour. Selective breeding of sables for the fur industry have resulted in an even wider variety of coat colours such as white-spotted, black, golden, speckled, or “blue” fur.^(1)(2)(3)

Habitat

Sables live primarily in dense coniferous taiga and mixed forest, and are associated with spruce, larch, pine, and birch trees.⁽¹⁾ They are frequently found living in swamps, bogs, and alongside rivers, and are reported to be strong swimmers.⁽⁴⁾ In China they are mostly found in montane forests far from human settlements.⁽⁵⁾

They establish multiple dens, making permanent winter and maternal dens and many temporary dens throughout the rest of the year. Dens may be made in hollow trees, holes in the ground, rock crevices, or under rocks, logs, tree snags, and roots. There may be a burrow several metres long that leads to the nesting chamber, which is lined with dry vegetation, lichens, fur, feathers, wool, or down.⁽⁴⁾⁽⁶⁾

Behaviour

The sable is a solitary opportunistic predator that hunts by day or night. It is somewhat less arboreal than other martens and spends most of its time on the ground. It can climb trees rapidly to escape threats but does not hunt in or travel through the forest canopy like other Martes. They have a keen sense of smell and communicate primarily by scent, but also possess acute hearing and possibly good vision as well.

They are territorial but somewhat less so than other martens. Home ranges vary from 0.5 to 30 square kilometres. Once a territory is established a sable will rarely venture away; thus trespassing, and thereby territorial aggression, is reduced. Territorial aggression unexpectedly decreases with higher population density, as young sables will apparently opt to migrate away rather than challenge a resident adult for territory. Young sables may travel over 70 kilometres when migrating and sometimes migrate in groups.

Like most mustelids, they are very active hunters and patrol their territory tirelessly in search of food, travelling up to 19 kilometres (11.8 miles) per day. They are well-adapted to hunting in frigid northern Asian winters, having the lowest weight load on their paws of any Old World marten and being small enough to access subnivean spaces in search for rodents. They will, however, hunker down in their dens in weather below -30° C (-22° F) or during heavy snowstorms.^(1)(4)(5)(7)

Reproduction

Mating season for M. zibellina is June-August. They exhibit delayed implantation, with implantation occurring February-March. Birth is given to one to five (average three) kits in late March-April. Sables are induced ovulators, and periodically go into estrus during mating season until ovulation is successfully induced. Females are mated multiple times per estrus, and ovulation usually does not occur until the second mating. Copulation occurs on the ground or in trees and lasts from 30 minutes to two hours.⁽⁴⁾⁽⁸⁾

Kits are altricial and weigh 30 to 35 grams (1.6 to 1.2 ounces) at birth. Eyes open at 30 to 36 days. Kits emerge from the den at 38 days old. They are weaned at seven to eight weeks old, but start accepting animal food at 50 to 52 days. Full size is reached at 12 to 16 weeks. They learn hunting skills through constant play until they are ready to begin dispersing for new territory, usually some time in August.

Sexual maturity is reached at 15 to 16 months. Age at first mating is around 27 months for males, and 15 to 39 months for females. Females are most fecund from 5 to 8 years old, but fecundity is reduced in times of scare prey.^(1)(4)(6)(8)

Diet

Sables have an omnivorous diet typical among Martes. Most of their diet consists of meat but plant matter is seasonally important. They are known to eat mice, pika, white hare, salmon, grouse, young birds, insects, earthworms, mollusks, fruit, berries, acorns, and especially pine nuts. The predatory instinct reportedly weakens when plant foods are abundant. Sables occasionally cache extra food, especially when in captivity. They may sometimes feed on carrion.

Large male sables are capable of bringing down surprisingly large prey such as capercaillie and, when rodent food is scarce, musk deer. Musk deer (which are usually ten times the size of a sable) are weakened by bites to the legs and abdomen and are ultimately killed by a bite to the neck, usually toward the atlas by the base of the skull. Multiple sables have been observed feeding on one musk deer carcass with no agonistic behaviour between them.^(1)(4)(5)(7)

Predators

Adult sables are generally resistant to predation but may fall prey to wolves, foxes, the wolverine, tigers, lynx, eagles, large owls, and perhaps even the yellow-throated marten.⁽¹⁾

The sable is unlikely to ever become globally endangered (again), but regional populations may be threatened by wildfires, habitat loss, or overhunting.⁽⁴⁾

Fur value

Sables have a long history of exploitation by the fur trade that continues today. Until the discovery of the sea otter in the Kamchatka peninsula in the 1740s (whose warmer, silver-tipped fur was considered even more valuable), sable fur was long considered the most luxurious and desirable, with each pelt commanding a small fortune.^(9)(10) One sable pelt could afford a Siberian hunter one cow, and fifty pelts would make him wealthy for life.⁽⁴⁾ The Qing Dynasty levied a tax of one sable pelt per year from every rural official, soldier, and hunter; these furs would make exclusive garments for the aristocracy and were forbidden to be worn by the lower classes.⁽⁵⁾

Predictably this incredible value led to a severe decline in sable populations, and by the 1600s the sable was nearly exterminated (the sea otter did not fare any better). For the following 300 years conservation attempts were consistently foiled by poaching and the population did not substantially recover. In the early-mid 1900s a combination of government regulations, war outbreaks, declining fur prices, and reintroductions reduced pressure enough for sable numbers to increase, and today the population is estimated at over a million. Some 300,000 wild sables are killed for the fur trade annually, and a few tens of thousands are raised and slaughtered on fur farms.⁽⁷⁾

The influence of the sable fur trade is reflected in the use of the term “sable” to refer to some black-furred animal breeds, and its use to mean “black” in traditional European heraldry—akin to the use of “ermine” to mean a pattern of white with black spots.

In social media

Some people keep rescued sables as pets in Russia. There are many videos and photos of a rescued sable named Buddy being uploaded to the social discussion platforms X (formally known as Twitter) and Reddit. Beware of the comments section on both of these, as you will come across many inaccurate claims and blind guesses over what the animal is. Though rarely credited, the original creator of these media and caretaker of the sable can be found on the TikTok account SableBuddy. You can also find videos of Buddy on the YouTube account BuddyPositive.

Body length: 38–56 cm / 15–22 in (males), 35–51 cm / 14–20 in (females)
Tail length: 9–12 cm / 3.5–4.7 in (males), 7.2–11.5 cm / 2.8–4.5 in (females)
Weight: 0.88–1.8 kg / 1.94–3.97 lb
Lifespan: Up to 8 years (wild), up to 20 years (captivity)
Range: Most of North Asia and parts of Northeast Europe.
Conservation status: Least concern
Subfamily: Guloninae
Recognised subspecies⁽¹¹⁾

References

#8 Yellow-Throated Marten (Martes flavigula)

The yellow-throated marten, also known as the kharza, is native to parts of East Asia and much of Southeast Asia.

Appearance

A bulky marten that gives the impression of strength and power, yet they are every bit as elegant and nimble in their manner of locomotion as the smaller members of the family. The almost monkey-like tail is longer than the head and body combined, serving as counterbalance when climbing tall trees. The ears are proportionally small and placed lower on the head than they are in the other martens. The paw pads are large, exposed, and typically bright pink in colour.

The yellow-throated marten is unmistakable with their unique brightly coloured fur, consisting of a blend of black, white, golden-yellow and brown. The dark brown of the head, neck, paws, hind limbs and tail contrasts the lighter fur on the body and throat, though some subspecies can be darker or lighter on the body with less contrast. Some specimen even lack the dark markings and are white in place of brown. The yellow throat is indeed a vibrant yellow, but not only so—there is a white or cream patch in the middle. It has relatively short fur compared to the Eurasian pine marten, sable, and beech marten. One or more digits on their front paws can sometimes be white, cream, or yellowish in colour.

They look similar in appearance to the Nilgiri marten, but their skulls are not as flat as their cousin. The fur on the Nilgiri marten’s back is usually dark brown in colour compared to the yellow-throated marten’s more common yellow or lighter brown. They also differ in that, unlike the Nilgiri marten, the yellow-throated marten typically has yellow fur that runs from the neck to as far back as the hips.

Habitat

Yellow-throated martens may be found in montane taiga, swamps, river and stream valleys, flood plains, and in tropical, subtropical, and temperate broadleaf, bamboo, and coniferous forests.⁽¹⁾⁽²⁾ They are strongly associated with the preferred habitat of musk deer (Moschus sp.) in regions where musk deer are important prey.⁽¹⁾

Information on denning behaviour for the yellow-throated marten is not readily available.

Behaviour

Reproduction

Information on reproduction in Martes flavigula is scarce. There are indications that yellow-throated martens are monogamous, but this is not confirmed. Males are reported to fight for mates during mating season, which lasts June to mid-July. There are usually two or three kits in a litter, rarely more than four.⁽¹⁾

Diet

Predators

The yellow-throated marten is generally resistant to predation, but is probably occasionally taken by larger predators such as Siberian tigers and Asian black bears where these species are sympatric.⁽⁶⁾⁽⁷⁾

Body length: 50–71.9 cm / 19.7–28.3 in (males), 50–62 cm / 20–24 in (females)
Tail length: 37–45 cm / 14.5–18 in
Weight: 2.5–5.7 kg / 5.5–12.6 lb (males), 1.6–3.8 kg / 3.5–8.4 lb (females)
Lifespan: Unknown (wild), up to 16 years (captivity)
Range: Parts of East Asia and much of Southeast Asia.
Conservation status: Least concern
Subfamily: Guloninae
Recognised subspecies⁽⁸⁾

References

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