These langurs are not known to have any particular benefit to humans.
A characteristic shared among most of P. thomasi's predators is the ability to climb trees. Predators such as reticulated pythons, clouded leopards, tigers, and golden cats are often successful in capturing Thomas’s langurs. Because these langurs are able to move swiftly through branches, their predators have been found to attack only when the distance between them and their prey is very short. Predators are more effective when attacking P. thomasi on the ground rather than in trees. Because of this, the most dangerous area for these monkeys is in the lower strata of the forest, which is 0 to 10m.
Thomas' langurs rely on two valuable forms of protection: their arboreal habits and the alarm calls that are produced when groups are around. Thomas’s langurs climb down from trees more often when they are surrounded by neighbors.
Females are more prone to predation due to their preference for snails and their smaller canines. Males are often found nearby in trees looking out for predators when females venture down to the ground by themselves.
Known Predators:
Presbytis thomasi has a very distinct appearance. Due to their unique facial coloration, it is easy to distinguish North Sumatran leaf monkeys from other primates. The white fur on the underside and arms (which contrasts with the black fur surrounding the rest of the body) continues up around the neck. Two other white stripes, starting from the top of the head, run down the sides, come together in a V-shape at the eyes and encircle them. A purple-silver colored inner layer forms rings around the orange-brown eyes. Inside of the dark tint, one can see the pinkish skin of Thomas's langur. This same pinkish skin covers the muzzle.
The average size of Thomas's langur is 6.69 kilograms for adult females and 6.67 kilograms for adult males. The tail length is between 500 and 850 mm, and the head and body length ranges between a mere 420 and 620 mm.
Range mass: 5 to 8.1 kg.
Range length: 92 to 147 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
The average lifespan of P. thomasi is 20 years. In captivity, the average lifespan is 29 years. The nine-year difference may be due to numerous factors such as the destruction of habitat, hunting by humans, the presence of natural predators, and attacks between neighboring groups.
Average lifespan
Status: wild: 20 years.
Average lifespan
Status: captivity: 29 years.
When searching through tropical rainforests, rubber plantations, and both primary and secondary forests, one is able to encounter Thomas’s langur. Since it is arboreal, one usually needs to search high in the trees to find this unique species. However, its positioning in the trees depends on what time of day it is. While it is taking a nap during the day, it selects a tree that tends to have lots of twigs and leaves for protection from the harsh sunlight. However, when it is sleeping at night, it sleeps in the top of a tall tree that faces the open areas.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
Presbytis thomasi is one of several langurs found in the Oriental islands. However, its geographic range is fairly limited. Its native home consists of North Sumatra of Indonesia—more specifically, north of Sungai Wampu and Sungai Simpang Kiri.
Biogeographic Regions: oriental (Native )
Other Geographic Terms: island endemic
This leaf-monkey’s diet is primarily centered around fruits, leaves, and seeds. However, it will eat other things such as flowers, bark, twigs, stalks of coconuts, leaf stalks, birds, bird eggs, algae, and some insects. Water is made available in tree holes. Occasional visits to the ground are made in order to obtain ants, toadstools, soil, and snails. Large peaks in foraging occur three times per day, accompanied by resting in the lower portions of trees. Foraging behavior is highly influenced by the risk of predation.
Animal Foods: birds; eggs; insects; mollusks
Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; fruit; flowers; algae
Other Foods: fungus
Primary Diet: herbivore (Folivore , Frugivore , Granivore )
Because of its preference for fruits, flowers, and seeds, one can infer that P. thomasi may disperse seeds and help pollinate plants while feeding. Like many primates, P. thomasi may also be a host to parasites such as fleas and ticks. To the extent that these monkeys serve as prey for other animals, they may impact predator populations.
Ecosystem Impact: disperses seeds; pollinates
Due to their primary diet of fruits, leaves, and seeds, Thomas's langurs are known to disrupt the crops of neighboring humans.
Negative Impacts: crop pest
Due to an increase in the availability of firearms and the destruction of forests in Sumatra, P. thomasi has to face losing its habitat and being hunted by neighboring humans. Another factor which may be responsible for declining populations is habitual infanticide that persists in this species. This behavior has been known to have increased in recent years; however, an increase in awareness has indicated that this behavior is very important to the species.
US Federal List: no special status
CITES: appendix ii
IUCN Red List of Threatened Species: vulnerable
Vocal communication is at its most intense and frequent at dawn. It is utilized in a variety of situations such as relocation, attacking, establishing sleeping positions, defending territory and mates. Vocalizations are accompanied by olfactory communication when mating is intitiated.
Thomas' langurs use numerous types of vocal calls. For example, an alpha male tends to make a series of “choom” sounds when he is excited; however, when he is involved in an inter-troop or group-troop encounter, he makes a series of “kak” and “ngkung” sounds. Similarly, when threatened, juveniles make an alternating series of “kek”s and “wek”s. Aggressive females make “kuk” sounds.
Vocal and visual communication develop as these monkeys mature. In infant P. thomasi, communication is restricted to whining and squealing. Once an individual becomes a juvenile, its abilities have broadened to screaming, grimacing, slapping the ground, present, alarm barking, staring, and threat bobbing. Finally, as an adult, it no longer squeals or screams, but barks and partakes in dominance fighting.
As in all primates, tactile communication, between mates, rivals, as well as between mothers and their offspring is important. Tactile communication includes grooming, reassurance, and aggression.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: choruses ; pheromones
Perception Channels: visual ; tactile ; acoustic ; chemical
The mating system of P. thomasi is debated. In the Encyclopedia of Mammals, it is noted that the species is a monogamous primate. The female initiates the mating by performing various acts to persuade her male counterpart, such as releasing certain smells and displaying genitalia.
However, others dispute the monogamy of the species. Steenbeck, et al. (1999) states that within groups, there are often several females and one breeding male. A possible resolution between the two observations is that only one of the females in the group breeds with the male while the other females help raise the young.
Mating System: monogamous ; cooperative breeder
There is no specified breeding interval for Thomas’s langurs. However, even though the breeding season is not restricted, there tends to be an increase in mating when the following weaning period is expected to correspond with an abundance of food. The gestation period lasts 5 to 6 months. At the end of gestation, female P. thomasi produce one young one young at a time. Females rarely produce more than one offsrping at a time, and never more than two. Weaning occurs at 12 to 15 months, after which an offspring is supposed to become independent. Although they are fully independent, juveniles do not reach sexual maturity until 4 or 5 years of age.
Breeding interval: Breeding can occur every 1.5 to 2 years.
Breeding season: The breeding season of these monkeys is not restricted.
Range number of offspring: 1 (low) .
Average number of offspring: 1.
Range gestation period: 5 to 6 months.
Range weaning age: 12 to 15 months.
Range time to independence: 15 to 18 months.
Average age at sexual or reproductive maturity (female): 4 years.
Range age at sexual or reproductive maturity (male): 4 to 5 years.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
When caring for her young, the mother removes herself from the dominance structure. Other females of the group are often attracted to the young due to the distinct coloring, and so they care for and protect the young whenever possible. As soon as the infant becomes upset or distraught, another female quickly tries to comfort it. The male infant has no contact with a male adult until he is 10 months old. During pre-weaning, the young has to learn what to eat, what to avoid, and other behavioral tactics in order to survive.
The male infant has no contact with a male adult until he is 10 months old. A female infant, however, has no contact with an adult male until she is 3.5 to 4 years old. Often during weaning, a male within the group or an outside group commits infanticide, killing an infant so that the mother can regain her normal cycle of fertility faster than she would if her child were still alive. This may explain the delay in contact between young and adult males.
Parental Investment: precocial ; pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); extended period of juvenile learning
El langur de Thomas (Presbytis thomasi) és una espècie de primat de la família dels cercopitècids. És endèmic d'Indonèsia. El seu hàbitat natural són els boscos secs tropicals o subtropicals. Està amenaçat per la pèrdua d'hàbitat.[1]
El langur de Thomas (Presbytis thomasi) és una espècie de primat de la família dels cercopitècids. És endèmic d'Indonèsia. El seu hàbitat natural són els boscos secs tropicals o subtropicals. Està amenaçat per la pèrdua d'hàbitat.
Der Thomas-Langur (Presbytis thomasi) ist eine Primatenart aus der Gruppe der Schlankaffen (Presbytini).
Thomas-Languren sind wie alle Mützenlanguren relativ kleine, schlanke Primaten mit langen Hinterbeinen und einem Schwanz, der länger als der Körper ist. Das Durchschnittsgewicht beträgt 6,7 Kilogramm, ein Geschlechtsdimorphismus ist kaum vorhanden. Ihr Fell ist am Rücken und an der Außenseite der Gliedmaßen grauschwarz und am Bauch und an der Innenseite der Gliedmaßen weißlich gefärbt. Auffällig ist der Kopf: Von der Spitze des Haarschopfes erstrecken sich zwei weiße Streifen V-förmig bis zu den Augen. Die orangebraunen Augen sind von silberfarbenen, weißgeränderten Kreisen umgeben.
Thomas-Languren leben in der Provinz Aceh im Norden der indonesischen Insel Sumatra. Ihr Lebensraum sind Wälder, sie sind aber auch in Kautschuk-Plantagen zu finden.
Diese Primaten sind vorwiegend in den Bäumen zu finden, manchmal kommen sie aber auch zur Nahrungssuche auf den Boden. Sie sind tagaktiv, haben aber ihre Aktivitätshöhepunkte am Morgen und am Nachmittag und halten mittags eine Rast. In den Bäumen bewegen sie sich entweder vierbeinig oder mittels Springen fort.
Sie leben in Gruppen von 3 bis 21 Tieren. Dies sind Haremsgruppen, das heißt eine Gruppe besteht üblicherweise aus einem Männchen, mehreren Weibchen und dem dazugehörigen Nachwuchs; die übriggebliebenen Männchen bilden oft Junggesellengruppen. Die Weibchen etablieren eine Rangordnung, die vor allem bei geringem Nahrungsangebot zum Vorschein kommt. Übernimmt ein neues Männchen eine Haremsgruppe, kommt es oft zum Infantizid, das heißt, dass das Männchen die von seinem Vorgänger gezeugten Kinder tötet, um selbst mit den Weibchen Nachwuchs zeugen zu können. Manchmal gehen die Weibchen dem aus dem Weg, indem sie im Fall einer Übernahme ihre Gruppe verlassen. Überhaupt scheint es relativ häufig zu sein, dass Weibchen ihre Gruppe verlassen, auch um Gruppen nicht zu groß werden zu lassen.
Die Gruppen sind territorial, die Streifgebiete der Gruppen überlappen sich aber. Begegnungen zweier Gruppen verlaufen oft aggressiv, mit lautem Geschrei und nötigenfalls mit Handgreiflichkeiten versuchen sie die Gegner zu vertreiben.
Thomas-Languren sind vorwiegend Pflanzenfresser, wobei junge Blätter und Früchte den Hauptanteil ausmachen. Daneben verzehren sie auch Blüten, Samen und andere Pflanzenteile. Auf den Boden kommen sie, um Pilze, hinuntergefallene Früchte, Kleintiere wie Insekten und Schnecken und manchmal auch Erde zu fressen.
Es gibt keine feste Paarungszeit. Nach einer fünf- bis sechsmonatigen Tragzeit bringt das Weibchen ein einzelnes Jungtier zur Welt. Dieses hat zunächst ein weißes Fell. Es wird nach 12 bis 15 Monaten entwöhnt und mit 4 bis 5 Jahren geschlechtsreif. Die Männchen und oft auch die Weibchen verlassen zu diesem Zeitpunkt ihre Geburtsgruppe.
Die Hauptbedrohungen für den Thomas-Languren stellen die Lebensraumzerstörung und die Bejagung dar. Verglichen mit anderen südostasiatischen Primaten ist er aber noch relativ häufig, die IUCN listet ihn als gering gefährdet.
Der Thomas-Langur (Presbytis thomasi) ist eine Primatenart aus der Gruppe der Schlankaffen (Presbytini).
Thomas's langur (Presbytis thomasi), also known as the North Sumatran leaf monkey or Thomas's leaf monkey, is a species of primate in the family Cercopithecidae. It is endemic to northern Sumatra, Indonesia. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss.[2] Its native names are reungkah in Acehnese and kedih in Alas.[3]
Thomas's langur (Presbytis thomasi), also known as the North Sumatran leaf monkey or Thomas's leaf monkey, is a species of primate in the family Cercopithecidae. It is endemic to northern Sumatra, Indonesia. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss. Its native names are reungkah in Acehnese and kedih in Alas.
Thomas's langur (Presbytis thomasi) from Bukit Lawang, North SumatraEl langur de Thomas (Presbytis thomasi) es una especie de primate catarrino de la familia Cercopithecidae.[2]
Es endémico de Sumatra (Indonesia). Su hábitat natural es el bosque tropical y subtropical. Se encuentra amenazado por la pérdida de hábitat.[1]
El langur de Thomas (Presbytis thomasi) es una especie de primate catarrino de la familia Cercopithecidae.
Cría de langur de Thomas.Es endémico de Sumatra (Indonesia). Su hábitat natural es el bosque tropical y subtropical. Se encuentra amenazado por la pérdida de hábitat.
Presbytis thomasi Presbytis generoko animalia da. Primateen barruko Colobinae azpifamilia eta Cercopithecidae familian sailkatuta dago
Presbytis thomasi
Le Semnopithèque de Thomas[1] (Presbytis thomasi) est une espèce qui fait partie des mammifères Primates. C’est un singe de la famille des Cercopithecidae dont les populations sont vulnérables.
Synonyme : Presbytis nubilus Miller, 1942.
Presbytis thomasi est présent sur l'île de Sumatra, en Indonésie. Cependant, sa zone géographie d'habitation est relativement limitée. L'espèce se situe plus précisément au nord du Sungai Wampu[2]. Cette dernière a été déclarée vulnérable en 2008[3].
Cette espèce recherche davantage la hauteur et aime grimper en haut des arbres. Mais leur position dans la forêt dépend de l'heure de la journée. Lorsqu'il se repose durant la journée, il cherche des arbres feuillus pour se protéger du soleil tapant. Cependant, le soir venu, ce dernier recherche la cime des arbres de manière à observer le panorama qui s'offre à lui[2].
Presbytis thomasi
Le Semnopithèque de Thomas (Presbytis thomasi) est une espèce qui fait partie des mammifères Primates. C’est un singe de la famille des Cercopithecidae dont les populations sont vulnérables.
Synonyme : Presbytis nubilus Miller, 1942.
Kedih (Presbytis thomasi) adalah spesies primata yang tergolong dalam famili Cercopithecidae. Hewan ini merupakan hewan endemik di utara Sumatra, Indonesia. Habitat alaminya adalah hutan tropis kering atau subtropis. Hewan ini terancam oleh pengrusakan habitat. Nama aslinya adalah reungkah di Aceh dan kedih di Alas.[1]
Kedih (Presbytis thomasi) adalah spesies primata yang tergolong dalam famili Cercopithecidae. Hewan ini merupakan hewan endemik di utara Sumatra, Indonesia. Habitat alaminya adalah hutan tropis kering atau subtropis. Hewan ini terancam oleh pengrusakan habitat. Nama aslinya adalah reungkah di Aceh dan kedih di Alas.
Il presbite di Thomas (Presbytis thomasi (Collett, 1893)) è una specie di primate della tribù dei Presbytini.
Il presbite di Thomas, come tutti i presbiti, è un primate relativamente piccolo e snello con zampe posteriori lunghe e una coda più lunga del corpo. Il peso medio si aggira sui 6,7 chilogrammi e il dimorfismo sessuale è quasi inesistente. La pelliccia è grigio-nera sul dorso e sulla parte esterna degli arti e biancastra sul ventre e sulla parte interna degli arti. L'aspetto della testa è caratteristico: dalla sommità della testa si estendono due strisce bianche a forma di V fino agli occhi. Gli occhi, di colore marrone-arancio, sono circondati da cerchi argentei bordati di bianco.
Il presbite di Thomas vive nella provincia di Aceh, nella parte settentrionale dell'isola indonesiana di Sumatra. Abita nelle foreste, ma si può trovare anche nelle piantagioni di caucciù.
Questi primati vivono principalmente sugli alberi, ma a volte scendono a terra per nutrirsi. Sono diurni, ma il loro picco di attività si riscontra al mattino e al pomeriggio, mentre durante le ore centrali della giornata si fermano per riposare. Sugli alberi si muovono a quattro zampe o saltando.
Vivono in gruppi composti da 3 a 21 esemplari. Tali gruppi in realtà sono degli harem costituiti da un maschio e da diverse femmine con la prole; i maschi rimanenti spesso formano gruppi di scapoli. Le femmine stabiliscono una gerarchia che è particolarmente evidente quando c'è poco cibo a disposizione. Se un nuovo maschio prende il controllo di un harem, spesso si verificano casi di infanticidio, il che significa che il maschio uccide i piccoli concepiti dal suo predecessore per poter concepire la propria prole con le femmine. A volte le femmine evitano questo lasciando il gruppo nel caso arrivi un nuovo maschio dominante. In linea generale, sembra relativamente comune che le femmine abbandonino il proprio gruppo, anche per non far diventare i gruppi troppo numerosi.
I gruppi sono territoriali, ma i confini dei vari territori si sovrappongono. Gli incontri tra due gruppi sono spesso aggressivi: i vari membri, infatti, cercano di scacciare gli avversari con urla e, se necessario, con scontri fisici.
I presbiti di Thomas sono principalmente vegetariani: foglie giovani e frutti costituiscono la parte principale della dieta. Inoltre, consumano anche fiori, semi e altre parti di piante. Scendono a terra per mangiare funghi, frutti caduti, piccoli animali come insetti e lumache e, talvolta, terra.
Non esiste una stagione degli amori vera e propria. Dopo un periodo di gestazione di cinque o sei mesi, la femmina partorisce un solo piccolo. Questo inizialmente è ricoperto da una pelliccia bianca. Viene svezzato dopo 12-15 mesi e raggiunge la maturità sessuale tra 4 e 5 anni. A questo punto, i maschi, e spesso anche le femmine, lasciano il gruppo dove sono nati.
Le principali minacce per il presbite di Thomas sono la distruzione dell'habitat e la caccia, ma rispetto ad altri primati del Sud-est asiatico è ancora relativamente comune e la IUCN lo classifica come specie vulnerabile.
Il presbite di Thomas (Presbytis thomasi (Collett, 1893)) è una specie di primate della tribù dei Presbytini.
De thomaslangoer (Presbytis thomasi) is een zoogdier uit de familie van de apen van de Oude Wereld (Cercopithecidae). De wetenschappelijke naam van de soort werd voor het eerst geldig gepubliceerd door Collett in 1892.
De soort komt voor in Indonesië.
Bronnen, noten en/of referentiesDe thomaslangoer (Presbytis thomasi) is een zoogdier uit de familie van de apen van de Oude Wereld (Cercopithecidae). De wetenschappelijke naam van de soort werd voor het eerst geldig gepubliceerd door Collett in 1892.
Presbytis thomasi[2][3][4] är en däggdjursart som först beskrevs av Robert Collett 1893. Presbytis thomasi ingår i släktet bladapor och familjen markattartade apor.[5][6] IUCN kategoriserar arten globalt som sårbar.[1] Inga underarter finns listade.[5]
Arten har på ryggen, kroppssidan och extremiteternas utsida en mörkgrå till svart päls. Buken, extremiteternas insida och halsen är vita. Kännetecknande är huvudets färgsättning. Kring det nästan nakna ansiktet med främst mörk lila till svart hud finns en smal krans av vit päls. Kring ögonen och vid munnen är huden mörk rosa. På hjässan bildar den vita pälsen ett V. Övriga delar av huvudet är täckta med svart päls som bildar vid kinderna ett tjockt skägg.[7]
Individerna når en kroppslängd (huvud och bål) av 42 till 62 cm, en svanslängd av 50 till 85 cm och en vikt mellan 5 och 8,1 kg (genomsnitt 6,7 kg).[7]
Denna primat förekommer på norra Sumatra. Den vistas där i låglandet och i låga bergstrakter upp till 1500 meter över havet. Habitatet utgörs av regnskogar och arten uppsöker även odlade regioner.[1]
Individerna är aktiva på dagen och de klättrar främst i växtligheten. Ibland kommer de ner till marken.[7]
Presbytis thomasi äter huvudsakligen blad och frukter som kompletteras med blommor, andra växtdelar och några ryggradslösa djur. Honor blir efter cirka fem år könsmogna men de får vanligen ett år senare sin första unge.[1]
En vanlig flock bildas av en hane, fem honor och deras ungar. Bland honorna etableras en hierarki. Dessutom finns ungkarlsflockar och ensamlevande hanar. När en främmande hane vill överta alfahanens position dödar den ofta flockens ungdjur. Honor försvarar ibland sin unge eller de flyttar till en annan flock. Honor lämnar sin ursprungliga flock även när den blivit för stor eller för att undvika inavel.[7]
För arten finns ingen särskild parningstid. Det är omstritt om bara den dominanta honan får para sig. Allmänt parar sig ingen annan hona när en hona är dräktig eller när den ger di åt sin unge. Mellan två kullar ligger 1,5 till 2 år. Efter 5 till 6 månaders dräktighet föds ett ungdjur eller i sällsynta fall tvillingar. Ungen diar sin mor 12 till 15 månader och den uppfostras även av flockens andra honor.[7]
Presbytis thomasi lever i naturen cirka 20 år och med människans vård kan den bli 29 år gammal.[7]
Presbytis thomasi är en däggdjursart som först beskrevs av Robert Collett 1893. Presbytis thomasi ingår i släktet bladapor och familjen markattartade apor. IUCN kategoriserar arten globalt som sårbar. Inga underarter finns listade.
Довжина голови й тіла: 42-61 см. Довжина хвоста: 50-85 см. Вага: 8 кг. Це відносно невеликі, тонкі примати з довгими задніми ногами і хвостом, який більший, ніж тіло. Статевий диморфізм не спостерігається. Хутро сіро-чорного кольору на спині і на зовнішніх сторонах кінцівок і білувате на животі і внутрішніх сторонах кінцівок. Помаранчеві-карі очі оточені сріблястого кольору, бахромчастими білими колами.
Цей вид зустрічається в північній частині Суматри (Індонезія). Цей вид був записаний у непорушеному первинному тропічному лісу поблизу дослідницької станції на Суматрі й, крім того, у мозаїці первинного та вторинного лісу з каучуковими плантаціями, і на гумових плантаціях на висотах від 0 до приблизно 1500 м.
Ці тварини в першу чергу листоїдні, й також харчуються фруктами і квітами, а іноді й стеблами кокосів, а також черевоногими, такими як наземні равлики. Ці примати в основному зустрічаються на деревах, іноді вони шукають їжу на землі. Вони є денними, але найбільш активні вранці і в другій половині дня. Вони живуть в групах 3-21 тварин. Це гаремні групи. Групи є територіальними.
Немає фіксованого шлюбного сезону. Після п'яти-шести місяців вагітності, самиця народжує одне дитинча, яке спочатку біле. Лактація триває 12—15 місяців, статева зрілість настає в 4-5 років.
Полювання, здається, не є серйозною загрозою, але втрата первинного середовища проживання через вирубку і перетворення в пальмові плантації на нафту, ймовірно, витісняють деякі групи населення. Занесений в Додаток II СІТЕС і охороняється індонезійським законодавством. Зустрічається, як відомо, принаймні в одному великому національному парку, Гунунг Лесер.
Presbytis thomasi là một loài động vật có vú trong họ Cercopithecidae, bộ Linh trưởng. Loài này được Collett mô tả năm 1892.[2]
Presbytis thomasi là một loài động vật có vú trong họ Cercopithecidae, bộ Linh trưởng. Loài này được Collett mô tả năm 1892.
Presbytis thomasi (Collett, 1893)
СинонимыPresbytis thomasi (лат.) — вид приматов из семейства мартышковых. Видовое латинское название дано в честь английского зоолога Олдфилда Томаса (1858—1929)[1].
Шерсть на нижней поверхности тела белая, на остальной части тела тёмно-серая. Две белых полосы на лбу соединяются книзу, образуя подобие буквы «V». Глаза оранжево-карие, кожа розовая. Средний вес этих приматов составляет 6,67 кг для самцов и 6,69 кг для самок. Длина тела от 420 до 620 мм, длина хвоста от 500 до 850 мм. Пищеварительная система приспособлена к перевариванию целлюлозы, которой богат рацион мартышек. Клыки самцов больше, чем клыки самок. Резцы длинные и узкие. Морда короткая и широкая. Большой палец редуцирован. Задние конечности длиннее передних.[2][3]
Встречаются на севере Суматры в Индонезии в провинции Ачех к северу от рек Симпангкири и Вампу.[4]
Дневные животные, часто спускающиеся на землю с деревьев в поисках пищи. Образуют группы размером от 3 до 20 особей. Группа обычно состоит из одного самца, нескольких самок и их потомства. В рационе фрукты, семена, листья, цветы, кора, ростки, а также мелкие животные, такие как насекомые, ящерицы, яйца птиц. Выраженного сезона размножения нет. Беременность длится от 5 до 6 месяцев. В помёте обычно один детёныш. До возраста 12 или 15 месяцев молодняк питается молоком матери. Половая зрелость наступает в возрасте от 4 до 5 лет.[3]
Международный союз охраны природы присвоил этому виду охранный статус «Уязвимый», поскольку, по оценкам 2008 года, численность популяции сократилась более чем на 30 % за 40 лет (3 поколения). Основная угроза популяции — разрушение среды обитания.[5]
Presbytis thomasi (лат.) — вид приматов из семейства мартышковых. Видовое латинское название дано в честь английского зоолога Олдфилда Томаса (1858—1929).
토마스잎원숭이, 북수마트라잎원숭이, 수마트라회색랑구르 또는 토마스랑구르(Presbytis thomasi)는 긴꼬리원숭이과에 속하는 영장류의 일종이다. 인도네시아가 원산지이다. 자연 서식지는 아열대 또는 열대 건조 기후의 숲이다. 서식지 감소로 인해 멸종될 위기에 처해 있다.[2]