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Tibetan Macaque - Macaca thibetana
Tibetan Macaque - Macaca thibetana

[Image: Tibetan-macaque-feeding-on-bamboo.jpg]

Scientific classification
Kingdom:  Animalia
Phylum:  Chordata
Class:  Mammalia
Order:  Primates
Suborder:  Haplorhini
Infraorder:  Simiiformes
Family:  Cercopithecidae
Genus:  Macaca
Species:  Macaca thibetana  (Milne-Edwards, 1870)

The Tibetan macaque (Macaca thibetana), also known as the Chinese stump-tailed macaque or Milne-Edwards' macaque, is found from eastern Tibet east to Guangdong and north to Shaanxi in China. It has also been reported from northeastern India. This species lives in subtropical forests (mixed deciduous to evergreen) at altitudes from 800 to 2,500 m (2,600 to 8,200 ft) above sea level.

[Image: 220px-Tibetan_Macaque_area.png]

Tibetan macaque range

There are four recognized subspecies:
  • M. t. thibetana
  • M. t. esau
  • M. t. guiahouensis
  • M. t. huangshanensis
Physical description
The Tibetan macaque is the largest species of macaque and one of the largest monkeys found in Asia. Only the Proboscis Monkey and the larger species of gray langur come close to match their size among Asian monkeys. Males are the larger sex, commonly attain a weight of 13 to 19.5 kg (29 to 43 lb) and length of 61 to 71 cm (24 to 28 in) long, with a maximum record weight of 30 kg (66 lb). Females, in contrast, weigh 9 to 13 kg (20 to 29 lb) and measure 49 to 63 cm (19 to 25 in) long. The stump-like tail adds only 4 to 14 cm (1.6 to 5.5 in), with females having a considerably shorter tail. The fur is well-suited to the species' cold environments being long, dense and brown on the back with creamy-buff to grey coloration on the underparts. Some adults are quite dark brown on the back, while others are basically a sandy yellowish-brown color. They have a prominent, pale-buff beard and long whiskers, but have a hairless face. The face is pale pinkish in males but is a more vivid, reddish-pink in females. The infants have silver-and-black fur that changes to its adult color at the age of two.

[Image: Tibetan-macaque-walking-across-grass.jpg]

The Tibetan macaque lives in mixed sex groups. In their complex social system, females remain for life in their natal group, but males disperse shortly after their adolescence (at about 8 years old). Macaque societies are hierarchical, with higher-ranking males getting better access to the resources, namely food and sexually-receptive females. Alpha males dominate the group, being those that are typically large, strong and newly mature. As they age, males tend to gradually lose their social standing and are frequently subject to challenges for dominance from other males. Such conflicts are frequently quite violent and males may kill each other in battle. Studies of Tibetan macaques at Mount Emei and Huangshan Mountains, China, found the average tenure for an alpha male only lasted about one year. When troop size becomes quite large (in the 40 to 50 range) and competition grows over increasingly stretched resources, some individuals (males, females and juveniles) split from the main group to form a new, smaller group, known as 'fissioning', and move on to a different home range. Usually, it is the lowest-ranking individuals that will split from the main group.

Females first breed at around five years of age. The gestation period is six months with a single offspring being produced at each pregnancy. Most infants being born in January and February. Young macaques are nursed for a year and may continue to do so longer if the female does not give birth again the following year. Males of the group may also be involved in alloparenting care.
This diurnal species spends most of its time on the ground, where it forages for leaves, fruit, grass and, to a lesser extent, flowers, seeds, roots and insects. When available, bamboo shoots, fruits and leaves are particularly favoured.

[Image: Tibetan-macaque-in-tree.jpg]


This species is classified as Near Threatened by the IUCN and is listed on Appendix II of the CITES list. Its main threats are all human-related. Principally, they are sensitive to habitat destruction, as they are tied closely to the forest. They are occasionally poisoned by herbicides and pesticides while eating and may catch diseases transmitted from humans. Illegal poaching may occur, with the flesh and the fur of the macaque being used.

Turmoil behind primate power struggles often overlooked by researchers
Social life of chimpanzees, macaques more complicated than studies suggest

Date:  September 17, 2018
Source:  Washington University in St. Louis
Social interactions can be intricate -- and not just among humans. A new study suggests that researchers may be overlooking some of these same complexities in the social relations of our closest primate relatives, such as chimpanzees and macaques.

[Image: 180917153657_1_540x360.jpg]
YeHong, a 13-year-old wild female Tibetan macaque, with her two offspring (juvenile and infant siblings) at the Valley of the Wild Monkeys in Mt. Huangshan in the Anhui Province of China. Tibetan macaques form strong relationships with their female relatives to maintain strict matrilineal social order and compete for resources.
Credit: Jessica Mayhew

Anyone who peruses relationship settings on social media knows that our interactions with other humans can be intricate, but a new study in Nature: Scientific Reports suggests that researchers may be overlooking some of these same complexities in the social relations of our closest primate relatives, such as chimpanzees and macaques.
"Our study confirms that the social relationships of nonhuman primates are extremely complicated, nuanced and multi-faceted," said Jake Funkhouser, lead author of the study and an anthropology doctoral student in Arts & Sciences at Washington University in St. Louis.
"It also suggests that existing research techniques for observing and measuring dominance are missing components of complexity that are critical for understanding the layers of diverse social relationships we see in the animal kingdom, our own human societies included," Funkhouser said.
Primatologists, such as Jane Goodall, Biruté Galdikas and Dian Fossey, have been studying primate behavior for decades, so the idea that chimpanzees and other primates have complex social relationships is nothing new.
While Funkhouser and colleagues affirm the importance of understanding these relationships, they argue that many long-established methodologies for assessing primate power struggles -- observations of fighting over food or mates -- may be too one-dimensional to capture the very complex social dynamics of primate relationships.
"The social relationships humans share with others cannot be accurately represented in simply 'dominant' or 'subordinate' terms," Funkhouser said. "Nor do our relationships readily transfer between settings; the aggressive or confrontational interactions we engage in with some are much different than the prosocial interactions we share with our spouse and best friends.
"Primate social relationships also are highly individualized and dependent on the partners involved and the social setting in which the interaction takes place. As the primate species with the most complex sociality, we humans should understand this pretty well," he said.
Across the animal kingdom, the term "social dominance" has been widely used as a descriptive shorthand to convey the behavioral characteristics and power status of individual animals and simplify the overall structure of social relationships within groups. However, investigators often differ in their definitions of dominance, the methods used to derive dominance and the statistical techniques used to rank individuals in a group. "This is precisely the problem we set out to explore," Funkhouser said.
In this study, Funkhouser and colleagues captured detailed behavioral data from the observation of captive chimpanzees at Chimpanzee Sanctuary Northwest in Cle Elum, Wash., and of wild Tibetan macaques of Mt. Huangshan in the Anhui Province of China.
By running these same behavioral data sets through a series of 69 different statistical analyses, they were able to compare and contrast how various methodologies ranked individuals' status and how these structures of dominance predicted patterns of other social behavior within the groups.
"When distilled, this paper simply highlights something intuitive about what being dominant means for a social animal: that social context matters," said co-author Jessica A. Mayhew, director of the Primate Behavior and Ecology program and assistant professor of anthropology and museum studies at Central Washington University in Ellensburg, Wash.
"The perception that dominance is solely about aggression, in other words who 'wins' and who 'loses' a contest, is only one piece of the larger group social dynamics," Mayhew said. "It's critical that as researchers we continue to acknowledge the context in which we collect our data because it influences our interpretation."
To exemplify this, at Chimpanzee Sanctuary Northwest, this study found that Jamie, an adult female chimpanzee who was retired from biomedical research, directs a lot of aggression toward the other chimpanzees. Therefore, through a competitive lens, Jamie is calculated to be the most dominant.
However, Negra -- an older adult female chimpanzee who was captured in the wild as an infant, used in biomedical research and then retired -- rarely engages in aggressive interactions but is most frequently the recipient of the groups' grooming efforts.
In Negra's case, she was calculated to be most dominant via the occupation of a privileged, or "respected," role in the group. These different results correspond with observations of chimpanzees' extremely complex and fluid social systems in the wild.
On the other hand, wild Tibetan macaques are often observed to have much stricter social rules, and this study picked up on those trends as well. These macaques follow species-typical trends and maintain one, mostly generalizable, dominance hierarchy that is stable across social contexts.
For example, young adult males TouGui and YeRongBing along with GouShan, a much older male, occupy the top of the dominance hierarchy, while females YeZhen, TouRongYu and TouTai occupy the bottom of the hierarchy.
Funkhouser, who studied primate behavior under Mayhew while pursuing his undergraduate and master's degrees at Central Washington University, is conducting his doctoral research under the supervision of Crickette Sanz, an associate professor of physical anthropology at Washington University.
Sanz is a leading scholar of primate behavior and co-principal investigator of the Goualougo Triangle Ape Project in the northern Republic of Congo.
In Funkhouser's doctoral work, he and Sanz plan to continue asking questions of behavioral adaptations, comparative social behavior and individual welfare of chimpanzee populations living in the wild, zoos and sanctuaries.
"Power dynamics among primates can have life or death outcomes; being an alpha can mean that a primate has access to higher quality food or more mates. The study of animal social relationships has been transformed over the past decade by a suite of new methods and analytical tools," Sanz said. "This study shows how these tools can be used to better understand social relationships among chimpanzees and macaques, two species with reputations for being highly political."

Story Source: Washington University in St. Louis. "Turmoil behind primate power struggles often overlooked by researchers: Social life of chimpanzees, macaques more complicated than studies suggest." ScienceDaily. (accessed September 18, 2018).

Journal Reference:
  1. Jake A. Funkhouser, Jessica A. Mayhew, Lori K. Sheeran, John B. Mulcahy, Jin-Hua Li. Comparative Investigations of Social Context-Dependent Dominance in Captive Chimpanzees (Pan troglodytes) and Wild Tibetan Macaques (Macaca thibetana). Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-32243-2
Theoretical definitions of dominance, how dominance is structured and organized in nature, and how dominance is measured have varied as investigators seek to classify and organize social systems in gregarious species. Given the variability in behavioral measures and statistical methods used to derive dominance rankings, we conducted a comparative analysis of dominance using existing statistical techniques to analyze dominance ranks, social context-dependent dominance structures, the reliability of statistical analyses, and rank predictability of dominance structures on other social behaviors. We investigated these topics using behavioral data from captive chimpanzees (Pan troglodytes) and wild Tibetan macaques (Macaca thibetana). We used a combination of all-occurrence, focal-animal, and instantaneous scan sampling to collect social, agonistic, and associative data from both species. We analyzed our data to derive dominance ranks, test rank reliability, and assess cross-context predictability using various statistical analyses. Our results indicate context-dependent dominance and individual social roles in the captive chimpanzee group, one broadly defined dominance structure in the Tibetan macaque group, and high within-context analysis reliability but little cross-context predictability. Overall, we suggest this approach is preferable over investigations of dominance where only a few behavioral metrics and statistical analyses are utilized with little consideration of rank reliability or cross-context predictability.
[Image: wildcat10-CougarHuntingDeer.jpg]
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