dcsimg

Lifespan, longevity, and ageing

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Maximum longevity: 37 years (captivity) Observations: One wild born animal was about 37 years old and still alive in captivity (Richard Weigl 2005).
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Associations

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Predators of Kloss' gibbons include leopards, snakes, and large birds of prey. Their social system means that many individuals are vigilant and will warn other members of the troup of impending danger.

Known Predators:

  • leopards (Panthera pardus)
  • large snakes (Serpentes)
  • large birds of prey (Falconiformes)
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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Nancy Shefferly, Animal Diversity Web
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Morphology

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Hylobates klossii has long forearms for brachiation. These tail-less, slender primates have dense, glossy, black hair with buttock pads and a large throat sac located under the chin. The throat sac helps to enhance their calls. Females are slightly larger than males, with males weighing about 5.6 kg and females weighing about 5.9 kg. Head and body length ranges from 440 mm to 635 mm.

Average mass: 5.7 kg.

Range length: 440 to 635 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger

Average mass: 5900 g.

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Life Expectancy

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The lifespan of Kloss' gibbons may be as long as 25 years. Other members of the genus Hylobates are known to live upwards of 44 years in captivity.

Range lifespan
Status: wild:
25 (high) years.

Range lifespan
Status: captivity:
37 (high) years.

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Habitat

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Kloss' gibbons can be found in the upper canopy of semi deciduous monsoon forests and tropical evergreen forests.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: rainforest

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Distribution

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Kloss' gibbons, Hylobates klossi, are found in Siberut, Sipura, North Pagai, and South Pagai in the Mentawai Islands, western Sumatra, and Indonesia.

Biogeographic Regions: oriental (Native )

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Untitled

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Hylobates means "dweller in the trees".

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Behavior

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Kloss' gibbons are known for their magnificent vocal communication. Females tend to have the most distinctive calls with a slow rise and fall, interrupted by a trill sequence. Male calls consist of moans and "quiver-hoots". Males will sing solos from 10 minutes up to 2 hours in both the pre- and post-dawn hours. Often, breeding pairs form duets together 2 to 3 hours after dawn, with the female's contribution lasting about 15 minutes. Occasionally, the young will join in the duet of their parents. It has been hypothesized that the duets are a means of intimidating neighbors to defend their territory and/or as a way to maintain social organization. Studies have shown that both males and females can be identified by the individuality of their calls, with each animal having its own unique voice.

Kloss' gibbons also use chemical, tactile, and visual modes of communication. Social grooming is an important form of social bonding and facial and body gestures are important ways of communicating among gibbons. Another important interaction is play behavior centered on the infant.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: duets ; choruses

Perception Channels: visual ; tactile ; acoustic ; chemical

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Nancy Shefferly, Animal Diversity Web
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Conservation Status

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The IUCN lists H. klossii as vulnerable due to the extent of occurrence and/or quality of habitat. The status of H. klossii is threatened because of an increased human population, hunting, and deforestation. CITES lists H. klossii on their Appendix I list.

US Federal List: no special status

CITES: appendix i

IUCN Red List of Threatened Species: endangered

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Benefits

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There are no known negative impacts of Kloss' gibbons.

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Nancy Shefferly, Animal Diversity Web
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Benefits

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Kloss' gibbons are a potential source of ecotourism dollars, as well as being important parts of a healthy ecosystem from which humans benefit.

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Nancy Shefferly, Animal Diversity Web
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Associations

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Kloss' gibbons act as important seed dispersers in their forest ecosystems.

Ecosystem Impact: disperses seeds

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Nancy Shefferly, Animal Diversity Web
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Trophic Strategy

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Kloss' gibbons are primarily frugivorous, preferring to eat fruits with high sugar content, such as figs, 72 percent of the time. They will also consume flowers, eggs, small vertebrates, and insects 25 percent of the time. This species tends to spend time apart from members of its own group while feeding -- up to 50 meters at times. In the wild, Kloss' gibbons have been observed to spend a large amount of feeding time searching for arthropods.

Animal Foods: birds; mammals; amphibians; reptiles; eggs; insects

Plant Foods: leaves; fruit; flowers

Primary Diet: herbivore (Frugivore )

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Nancy Shefferly, Animal Diversity Web
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Reproduction

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Kloss' gibbons are monogamous. Mated pairs of males and females, with their young, form the basic social unit.

Mating System: monogamous

The gestation period of H. klossii lasts 7 to 8 months, with one infant born every 2 to 3 years. Weaning occurs early in the second year of life. Kloss' gibbons reach sexual maturity at 6 to 7 years of age. Young do not usually disperse from their family unit until they reach late adolescence. The testicular sac in males is covered by short, sparse hairs. In females, the labia majora is prominent, making it difficult to distinguish males from females in the field.

Breeding interval: One infant is born every 2 to 3 years to an individual female.

Breeding season: These animals breed throughout the year.

Average number of offspring: 1.

Range gestation period: 7 to 8 months.

Range weaning age: 24 (high) months.

Range age at sexual or reproductive maturity (female): 6 to 7 years.

Range age at sexual or reproductive maturity (male): 6 to 7 years.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous

Average number of offspring: 1.

Males and females participate in caring for the young. Around the time of adolescence, males and females will disperse from their parent's group. Often parents will assist dispersing adolescents in obtaining territory by accompanying the young into new territory and threatening those occupying the new area.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning

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Marcoux, A. 2004. "Hylobates klossii" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_klossii.html
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Alix Marcoux, Michigan State University
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Barbara Lundrigan, Michigan State University
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Nancy Shefferly, Animal Diversity Web
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Biology

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Kloss's gibbon is an arboreal species, spending most of its time in the canopy. They are active in the day (2) and get around by swinging from branch-to-branch, their long hands forming perfect hooks for grasping the branches (5). They live in groups, consisting of a breeding pair and their offspring, with social grooming helping to maintain bonds (5). These groups defend a territory, with loud bouts of singing serving to proclaim ownership (2). Neighboroughing males chorus before dawn and females after dawn with a 50 second great call (6). As young males and females reach sexual maturity they will leave the family group, with the aim of finding a mate and establishing a new group (5). These gibbons feed mainly on fruit, but will also take flowers and some invertebrates to supplement the diet (5). Males and females form monogamous pairs. A single young is produced after a gestation period of seven to eight months. There is typically a gap of two to three years between each birth (2).
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Conservation

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Kloss's gibbon is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), which prohibits international trade in this species (3).
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Description

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Both male and female Kloss's gibbons have short, black hair throughout their lives. The chest is broad and the limbs are long (4), which aids in swinging from branch-to-branch, a form of locomotion known as 'brachiation' (5). The thumbs and big toes are also very long, and there is webbing between the digits of the hands and feet (4). There is a sac below the throat which is used to produce calls (5). The muzzle is relatively short, and the hair on the crown lies flat; in infants, however, this hair is erect (4).
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Habitat

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Inhabits tropical rainforest (2) and monsoon forest (5).
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Range

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Found on North and South Pagi, Sipora and Siberut, islands in the Mentawai group, West Sumatra in Indonesia (2).
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Status

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Classified as Vulnerable (VU A1c+2c, B1+2ac) on the IUCN Red List 2004 (1). Listed in Appendix I of CITES (3).
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Threats

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The main threat facing these gibbons is habitat destruction and degradation caused by human activities in the area (1). Hunting is also a problem, which worsens as habitat destruction continues, as it allows greater access into the forest (2).
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Kloss's gibbon

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Kloss's Gibbon
The Mentawai Islands

Kloss's gibbon (Hylobates klossii), also known as the Mentawai gibbon, the bilou or dwarf siamang, is an endangered primate in the gibbon family, Hylobatidae. It is identifiable in that it is all black,[4] resembling the siamang with its black fur, but is considerably smaller and lacks the siamang's distinctive throat pouch. Kloss's gibbon reaches a size 17 to 25 inches (44 to 63 cm) and weigh at most 13 pounds (6 kg). As is the case for all gibbons, they have long arms and no tail. Males and females are difficult to distinguish.[5]

Habitat

Kloss's gibbon exclusively lives on the Mentawai Islands that lie to the west of Sumatra.[1] The Mentawai Islands consist four main islands that are part of an island archipelago.[6] These islands are hearths of biodiversity, and are the homes of many endemic species.[6] It is a diurnal inhabitant of the rain forest that hangs in the trees from its long arms and rarely comes to the ground. Because Kloss's gibbon rarely comes out of the canopy, these gibbons use tree limbs to cross obstacles like bodies of water.[7] Like all species of gibbons it lives together in pairs that stake out a territory from approximately 49 to 74 acres (20 to 30 hectares) of size. This area is defended vehemently against other gibbons. Its diet consists mainly of fruits, occasionally also eating different plant parts, bird eggs, insects and small vertebrates.

Communication

Kloss's gibbon are unique gibbons because the two sexes do not vocalize songs in unison.[8] Male Kloss's gibbon sing before the sun rises and female Kloss's gibbon vocalize songs once the sun has risen.[8] Female Kloss's gibbon calls are unique and have slight variations in the different stages of the call.[9] The calls emitted by the females could offer other members of the species information about their position in the canopy.[9]

Reproduction

The reproductive cycle of Kloss's gibbon is similar to that of other gibbons. Every two to three years the female may give birth to a single young (with a gestation period of seven months). The young is weaned in the middle of its second year, and is fully mature in about seven years. Their life expectancy is about 25 years in the wild, and up to 40 years in captivity. Kloss's gibbons are monogamous, and male Kloss's gibbons use territory to attract and court possible mates.[10] Territories are often contested and Kloss's gibbons defend their territories with aggression and threats.[10] During courtship, males and females defend territory together, and mating only occurs after the females deems the male capable of defending a suitable territory.[10]

Diet

Kloss's gibbon are picky eaters, and never consume over-ripened fruit.[5] Kloss's gibbons diet consists of fruit, leaves, shoots, and insects.[5] Kloss's gibbons favorite fruit is figs, but these gibbons do not spend a lot of time eating figs because figs are scarce on the Mentawai Islands.[5]

Behavior

When Kloss's gibbons are observed by human researchers, they adapt and become less afraid, a process called habituation. Kloss's gibbons can become habituated to humans and will not flee when they are observed.[11] Unhabituated Kloss's gibbons sometimes exhibit a warning behavior in which they act as a lure toward people.[11] One male gibbon will produce warning calls and attract attention to himself while other members of his group make their escape.[11] Kloss's gibbons behavior help it stay cryptic, possibly to help them avoid hunting pressure.[11] Female Kloss's gibbons sing less frequently than males, and males only sing in the predawn when visibility isn't optimal for hunting.[11] Kloss's gibbons also exhibit less aggregate behavior like grooming and playing, possibly to reduce their visibility and stay hidden from hunters.[11]

Conservation

Kloss's gibbon is in jeopardy of going extinct.[8] Kloss's gibbon is classified as endangered by the IUCN (2021).[2] Recent estimates conclude that there are around 20,000 to 25,000 Kloss's gibbons alive in the wild, and its numbers are declining.[12] Over the last two and a half decades, the population size of Kloss's gibbon has fallen by 50%.[12] There are several threats that pose significant risk to Kloss's gibbon. Kloss's gibbon has no natural predators, and humans are the main threat to the existence of this primate.[7] Native peoples of the Mentawai Islands kill Kloss's gibbon and other endemic primates for subsistence, and also participate in poaching activities.[6] Globalization and industrialization in the Mentawai Islands are contributing toward the degradation of high quality habitat needed by Kloss's gibbon.[13] Road development and the adoption of air rifles are allowing natives to kill Kloss's gibbon easier and at higher rates.[13] Kloss's gibbon spends the majority of its time in the tree canopy, and as a result, this species requires undisturbed, old-growth forest habitats to sustain itself.[6] Kloss's gibbon is at risk due to habitat loss, as its homeland islands are suffering from deforestation.[6] Conservationists focused on improving Kloss's gibbons endangered status need to protect and preserve the high quality habitat needed by these gibbons.[6] Fragments of habitat need to be connected to allow movement without risk of exposure in highly modified areas.[6] Local government has been cooperating with global organizations such as UNESCO to raise awareness as well as increase the amount of protected land in the Mentawai Islands.[13]

References

  1. ^ a b Groves, C. P. (2005). "Order Primates". In Wilson, D. E.; Reeder, D. M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 179. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ a b Liswanto, D.; Whittaker, D.; Geissmann, T.; Whitten, T. (2020). "Hylobates klossii". IUCN Red List of Threatened Species. 2020: e.T10547A17967475. doi:10.2305/IUCN.UK.2020-2.RLTS.T10547A17967475.en. Retrieved 19 November 2021.
  3. ^ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  4. ^ Kloss Gibbon at the zoo
  5. ^ a b c d Whitten, Anthony J. (1982-02-08). "Diet and Feeding Behaviour of Kloss Gibbons on Siberut Island, Indonesia". Folia Primatologica. 37 (3–4): 177–208. doi:10.1159/000156032. ISSN 0015-5713. PMID 7076055.
  6. ^ a b c d e f g Yanuar, Ahmad (2018). "The Status of Primates in the Southern Mentawai Islands, Indonesia". Primate Conservation. Issue 32: 193–203 – via EBSCOhost.
  7. ^ a b Tenaza, R.R. (1975). "Territory and Monogamy Among Kloss' Gibbons (Hylobates klossii) in Siberut Island, Indonesia". Folia Primatologica. 24 (1): 60–80. doi:10.1159/000155685. ISSN 1421-9980. PMID 1140755.
  8. ^ a b c Höing, Andrea; Quinten, Marcel C.; Indrawati, Yohana Maria; Cheyne, Susan M.; Waltert, Matthias (February 2013). "Line Transect and Triangulation Surveys Provide Reliable Estimates of the Density of Kloss' Gibbons (Hylobates klossii) on Siberut Island, Indonesia". International Journal of Primatology. 34 (1): 148–156. doi:10.1007/s10764-012-9655-7. ISSN 0164-0291. PMC 3605491. PMID 23538477.
  9. ^ a b Haimoff, E.H.; Tilson, R.L. (1985-02-14). "Individuality in the Female Songs of Wild Kloss' Gibbons (Hylobates klossii) on Siberut Island, Indonesia". Folia Primatologica. 44 (3–4): 129–137. doi:10.1159/000156207. ISSN 0015-5713.
  10. ^ a b c Tilson, R. L. (1981-01-31). "Family Formation Strategies of Kloss's Gibbons". Folia Primatologica. 35 (4): 259–287. doi:10.1159/000155979. ISSN 0015-5713. PMID 7196868.
  11. ^ a b c d e f Dooley, Helen M.; Judge, Debra S. (2014-10-08). "Kloss gibbon (Hylobates klossii) behavior facilitates the avoidance of human predation in the Peleonan forest, Siberut Island, Indonesia". American Journal of Primatology. 77 (3): 296–308. doi:10.1002/ajp.22345. ISSN 0275-2565. PMID 25296898. S2CID 1616932.
  12. ^ a b Whittaker, Danielle J. (2005-10-19). "New population estimates for the endemic Kloss's gibbon Hylobates klossii on the Mentawai Islands, Indonesia". Oryx. 39 (4): 458. doi:10.1017/s0030605305001134. ISSN 0030-6053. S2CID 84629632.
  13. ^ a b c Whittaker, Danielle J. (May 2006). "A Conservation Action Plan for the Mentawai Primates". Primate Conservation. 20: 95–105. doi:10.1896/0898-6207.20.1.95. ISSN 0898-6207. S2CID 85765480.

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Kloss's gibbon: Brief Summary

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Kloss's Gibbon The Mentawai Islands

Kloss's gibbon (Hylobates klossii), also known as the Mentawai gibbon, the bilou or dwarf siamang, is an endangered primate in the gibbon family, Hylobatidae. It is identifiable in that it is all black, resembling the siamang with its black fur, but is considerably smaller and lacks the siamang's distinctive throat pouch. Kloss's gibbon reaches a size 17 to 25 inches (44 to 63 cm) and weigh at most 13 pounds (6 kg). As is the case for all gibbons, they have long arms and no tail. Males and females are difficult to distinguish.

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