Gee's golden langur

Discovery and etymology

The earliest record of the golden langur is in Pemberton's 1838 paper which states that "Griffith observed these monkeys near Tongso in Central Bhutan." However, Pemberton's work was lost and not rediscovered until the 1970s, the scientific discovery of the golden langur unfolded differently. In 1907, E. O. Shebbeare—who was out with some hunters and forest rangers—reported seeing a "cream coloured langur" in the vicinity of the Jamduar. However, neither a photograph nor a live or dead specimen was presented at that time. The first reference to the golden langur in print, as an animal of unidentified taxonomic status, was in a 1919 publication that stated: "Pithecus sp? – A pale yellow coloured langur is common in the adjoining district of Goalpara (Assam). Jerdon reported one from Terai, the adjacent district on the (west) side, which Blanford suggested might be P. entellus."

At around the time of India's independence in 1947 a number of other sightings were reported. In February 1947, in the Forest Rest House visitor's book in Raimona, a few miles south of Jamduar, C. G. Baron reported seeing some langurs whose "whole body and tail is one colour – a light silvery-gold, somewhat like the hair of a blonde." A year later, back in Jamduar, H. E. Tyndale, a tea planter, reported seeing "Sankosh cream langurs." However, it wasn't until a few years later that a focused effort to identify the golden langur was mounted by E. P. Gee, who traveled to Jamduar in November 1953. His team were able to observe three groups of golden langurs, all on the east bank of the Sankosh river. The first group was observed on the Bhutan side of the border; the second group, a large one of 30 to 40 individuals, a mile north of Jamduar on the Indian side; and a third group four to five miles (6.44 km to 8.05 km) south near Raimona. Colour movies of the second group were made by Gee.

In August 1954, Gee reported his findings to an expert at the Zoological Society of London, who advised that the golden langur might be a new species. In January 1955, Gee also reported his results to the Zoological Survey of India (ZSI) and, after showing his movies of the golden langurs, suggested that Jamduar be included in the then-upcoming ZSI-survey of that region. The suggestion received the support of Dr. Sunder Lal Hora, then Director of ZSI, and later that year six specimens of the golden langur were collected by the survey party. The following year, Dr. H. Khajuria, a taxonomist who studied the specimens, described the new species naming it Presbystis geei in honour of Gee.

Taxonomy

There are two subspecies of this species:

• Trachypithecus geei geei Khajuria, 1956
• Trachypithecus geei bhutanensis Wangchuk, 2003

Physical description

The coat of the adult golden langur ranges from cream to golden; on its flanks and chest the hairs are darker and often rust coloured; the coats of the juveniles and females are lighter, silvery white to light buff. The golden langur has a black face and a very long tail measuring up to 50 cm (19.69 in) in length. It has been noted that their fur changes colors according to the seasons.

Distribution

The regions of its distribution are very small; the main region is limited to an area approximately 60 miles square bounded on the south by the Brahmaputra River, on the east by the Manas River, on the west by the Sankosh River, all in Assam, India, and on the north by the Black Mountains of Bhutan, and the secondary region, 200 miles to the south-southeast, is in a small portion of the northwestern part of Tripura state. These biogeographical barriers are believed to have led to the radiation of species from the closely related capped langur (Trachypithecus pileatus). The best range maps so far are Choudhury (2002) and Choudhury (2008)

Behavior and ecology

For the most part, the langur is confined to high trees where its long tail serves as a balancer when it leaps across branches. During the rainy season it obtains water from dew and rain drenched leaves. Its diet is herbivorous, consisting of ripe and unripe fruits, mature and young leaves, seeds, buds and flowers.

It generally lives in troops of about 8 (but sometimes up to 50) with a ratio of several females to each adult male. The smallest golden langur troop was composed of four individuals, while the largest had 22, giving an average value of 8.2 individuals per troop. The adult gender ratio was 2.3 females to every male, although the majority of groups had only one adult male.

Conservation

They are listed in Appendix I of CITES and Schedule I of Wildlife Protection Act, 1972 (Indian law). Gee's golden langur is currently endangered with the current population trend as decreasing; its total Indian population is 1500 individuals. Bhutan has 4000 individuals. 93% of the population is found in contiguous forest, while the remaining 7% is found in several small isolated reserves. The population has declined by more than 30% in the last 30 years, and is expected to decline further in the near future. The scattering of golden langurs in small groups is not a good sign. The primate needs to be concentrated in viable areas.

On 5 June 2019, the district authorities of Bongaigaon district in Assam launched a project under the MGNREGA to plant guava, mango, blackberry and other fruit trees to ensure that the resident golden langurs of the Kakoijana reserved forest do not have to risk their lives to find food. Several golden langurs have died due to electrocution and in road accidents while looking for food beyond the reserve forests.

In 1988, two captive groups of golden langurs were released into two protected areas of the western region of the state of Tripura, India. As of 2000, one of these groups, consisting of six (and possibly eight) individuals in the Sepahijala Wildlife Sanctuary, had survived.

The relative death of infants and juveniles indicate a declining population with the habitat being degraded by human activity. A fragmented but protected population in a rubber plantation in the Nayakgaon, Kokrajhar, district of Assam increased in population from 38 individuals in 1997 to 52 in 2002. The population has also adapted to feeding on dry rubber seeds.