THE HIMALAYAN GRAY LANGURS

 

Gray langurs, also called Hanuman langurs and Hanuman monkeys, are Old World monkeys native to the Indian subcontinent constituting the genus Semnopithecus.^[1] Traditionally only one species Semnopithecus entellus was recognized, but since about 2001, additional species have been recognized. The taxonomy has been in flux, but currently eight species are recognized.

 

 

Gray langurs are terrestrial, inhabiting forest, open lightly wooded habitats, and urban areas on the Indian subcontinent. Most species are found at low to moderate altitudes, but the Nepal gray langur and Kashmir gray langur occur up to 4,000 m (13,000 ft) in the Himalayas.^[2][3]

 

These langurs are largely gray (some more yellowish), with a black face and ears. Externally, the various species mainly differ in the 

 

darkness of the hands and feet, the overall color and the presence or absence of a crest.

Langurs mostly walk quadrupedally and spend half of their time on the ground and the other half in trees. They will also make bipedal hops, climbing and descending supports with the body upright, and leaps. Langurs can leap 3.6–4.7 m (12–15 ft) horizontally and 10.7–12.2 m (35–40 ft) in descending.^[8]

 

Traditionally, only Semnopithecus entellus was recognized as a species, the remainder all being treated as subspecies. In 2001, it was proposed that seven species should be recognized.^[4] This was 

 followed in Mammal Species of the World in 2005,^[1] though several of the seven species intergrade, and alternative treatments exist where only two species (a northern and a southern) are 

 recognized.^[5]Phylogenetic evidence supports at least three species: a north Indian, a south Indian and a Sri Lankan one.^[9][10]

 

It has been suggested that the Semnopithecus priam thersites is worthy of treatment as a species rather than a subspecies, but at present this is based on limited evidence.^[11] During a study based on external morphology and ecological niche modelling in Peninsular India six main types were found, but continued to label all as subspecies. Coat color is highly variable, possible due to phenotypic plasticity and therefore of questionable value in species delimitation.^[12][13]

 

It has been suggested that Trachypithecus should be considered only a subgenus of Semnopithecus.^[5] If maintaining the two as separate monophyletic genera, the purple-faced langur and Nilgiri langur belong in Semnopithecus instead of their former genus Trachypithecus. At present it is unclear where the T. pileatus species group (consisting of the capped langur, Shortridge's langur and Gee's golden langur) belongs, as 

 

available mtDNA data place it in Semnopithecus, while Y chromosome data place it in Trachypithecus.^[9] A possible explanation for this is that the T. pileatus species group is the result of fairly recent hybridization between Semnopithecus and Trachypithecus.^[10]

Results of analysis of mitochondrial cytochrome b gene and two nuclear DNA-encoded genes of several colobine species revealed that Nilgiri and purple-faced langurs cluster with gray langur, while  

Trachypithecus species form a distinct clade.^[14] Since then, two other species have been moved from Trachypithecus to Semnopithecus:^[15][16]

 

 In addition, Semnopithecus dussumieri has been determined to be invalid.^{[12][16][17][18]} Most of the range that had been considered S. dussumieri is now considered S. entellus.^[15][16]

 

 

A 2013 genetic study indicated that while S. entellus, S. hypoleucos, S. priam and S. johnii are all valid taxa, there has been hybridization between S. priam and S. johnii.^[19] It also indicated that there has been 

 

some hybridization between S. entellus and S. hypoleucos where their ranges overlap, and a small amount of hybridization between S. hypoleucos and S. priam.^[19] It also suggested that S. priam and S. johnii diverged from each other fairly recently.^[19]

 

The entire distribution of all gray langur species stretches from the Himalayas in the north to Sri Lanka in the south, and from Bangladesh in the east to Pakistan in the west.^[20] They possibly 

 

occur in Afghanistan.^[5] The bulk of the gray langur distribution is within India, and all seven currently recognized species have at least a part of their range in this country.^[4

 

 Gray langurs can adapt to a variety of habitats.^[21] They inhabit arid habitats like deserts, tropical habitats like tropical rainforests and temperate habitats like coniferous forests, deciduous habitats and mountains habitats. They are found at sea level to altitudes up to 4,000 m (13,000 ft).^[2][3] They can adapt well to human settlements, and are found in villages, towns and areas with housing or agriculture.^[22] They live in densely populated cities like Jodhpur, which has a population numbering up to a million.^[23]

 

Gray langurs are diurnal. They sleep during the night in trees but also on man-made structures like towers and electric poles when in human settlements.^[24] When resting in trees, they generally prefer the highest branches.^[25]

 

 

Ungulates like bovine and deer will eat food dropped by foraging langurs.^[26] Langurs are preyed upon by leopards, dholes and tigers.^[27] Wolves, jackals, Asian black bears and pythons may also prey on langurs.

 

Gray langurs are primarily herbivores. However, unlike some other colobines they do not depend on leaves and leaf buds of herbs, but will also eat coniferous needles and cones, fruits and fruit buds, evergreen petioles, shoots and roots, seeds, grass, bamboo, fern rhizomes, mosses, and lichens. Leaves of trees and shrubs rank at the top of preferred food, followed by herbs and grasses. Non-plant material consumed include spider webs, termite mounds and insect larvae.^[28] They forage on agricultural crops and other human foods, and even accept handouts.^[29] Although they occasionally drink, langurs get most of their water from the moisture in their food.^[30]

 All-male groups tend to be the smallest of the groups and can consist of adults, subadults, and juveniles. Some populations have only multiple-male groups as mixed sex groups, while others have only one-male groups as mixed sexed groups.^[31]

 

 Some evidence suggests multiple-male groups are temporary and exist only after a takeover, and subsequently split into one-male and all-male groups.^[33]

 

 

Social hierarchies exist for all group types.^[34][35] In all-male groups, dominance is attained through aggression and mating success.^[36] With sexually mature females, rank is based on physical condition and age.^[37][38] The younger the female, the higher the rank. Dominance rituals are most common among 

 

high-ranking langurs.^[35] Most changes in social rank in males take place during changes in group members. An adult male may remain in a one-male group for 45 months.^[39] The rate of male replacement can occur quickly or slowly depending on the group.^[40]

 

 

Females within a group are matrilineally related. Female memberships are also stable, but less so in larger groups.^[32][37] Relationships between the females tend to be friendly. They will do various activities with each together, such as foraging, traveling and resting. They will also groom each other regardless of their 

 

rank. However, higher-ranking females give out and receive grooming the most.^[41] In addition, females groom males more often than the other way around.^[42] Male and female relationships are usually positive. Relationships between males can range from peaceful to violent. While females remain in their natal groups, males will leave when they reach adulthood.^[32] Relationships between groups tend to be hostile. High-ranking males from different groups will display, vocalize, and fight among themselves.

 

 In one-male groups, the resident male is usually the sole breeder of the females and sires all the young. In multiple-male groups, the highest-ranking male fathers most of the offspring, followed by the next-ranking males and even outside males will father young.

 

 

Female gray langurs do not make it obvious that they are in estrous. However, males are still somehow able to deduce the reproduction state of females.^[44] Females signal that they are ready to mate by shuddering the head, lowering the tail, and presenting their anogenital regions.^[45] Such solicitations do not always lead to copulation. When langurs mate, they are sometimes disrupted by other group members.^[39] Females have even been recorded mounting other females.^[46]

 

 

The gestation period of gray langur lasts around 200 days, at least at Jodhpur, India. In some areas, reproduction is year-around.^[45] Year-round reproduction appears to occur in populations that capitalize on human-made foods. Other populations have seasonal reproduction.^[39] Infanticide is common among gray 

langurs. Most infanticidal langurs are males that have recently immigrated to a group and driven out the prior male. These males only kill infants that are not their own.^[47] Infanticide is more commonly reported in one-male groups, perhaps because one male monopolizing matings drives the evolution of this trait. In multiple-male groups, the costs for infanticidal males are likely to be high as the other males may protect the infants and they can't ensure that they'll sire young with other males around. Nevertheless, infanticide does occur in these groups, and is suggested that such practices serve to return a female to estrous and gain the opportunity to mate.^[48]

 

 

Females usually give birth to a single infant, although twins do occur. Most births occur during the night.^[49] Infants are born with thin, dark brown or black hair and pale skin. Infants spend their first week attached to their mothers' chests and mostly just suckle or sleep.^[50] They do not move much in terms of 

 

 

locomotion for the first two weeks of their life. As they approach their sixth week of life, infants vocalize more.^[51] They use squeaks and shrieks to communicate stress. In the following months, the infants are capable of quadrupedal locomotion and can walk, run and jump by the second and third months. Alloparenting occurs among langurs, starting when the infants reach two years of age. The infant will be given to the other females of the group. However, if the mother dies, the infant usually follows.^[50] Langurs are weaned by 13 months.

 

 Gray langurs are recorded to make a number of vocalizations:

 

 Gray langurs have stable populations in some areas and declining ones in others.^[54] Both the black-footed gray langur and Kashmir gray langur are considered threatened.^[3][55] The latter is the rarest species of gray langur, with less than 250 mature individuals remaining.^[3]

 

In India, gray langurs number at around 300,000.^[56] India has laws prohibiting the capturing or killing of langurs, but they are still hunted in some parts of the country.^[12] Enforcement of these laws has proven to be difficult and it seems most people are unaware of their protection.^[57] Populations are also threatened by mining, forest fires and deforestation for wood.^[58]

Langurs can be found near roads and can become victims of automobile accidents. This happens even in protected areas, with deaths by automobile collisions making nearly a quarter of mortality in Kumbhalgarh Wildlife Sanctuary in Rajasthan, India.^[59] Langurs are considered sacred in the Hindu religion and are 

 

sometimes kept for religious purposes by Hindu priests and for roadside performances. However, some religious groups use langurs as food and medicine, and parts of gray langurs are sometimes kept as amulets for good luck.^[60]

 

 

Because of their sacred status and their less aggressive behavior compared to other primates, langurs are generally not considered pests in many parts of India. Despite this, research in some areas show high levels of support for the removal of langurs from villages, their sacred status no longer important.^[61] 

Langurs will raid crops and steal food from houses, and this causes people to persecute them.^[61] While people may feed them in temples, they do not extend such care to monkeys at their homes.^[62] Langurs stealing and biting people to get food in urban areas may also contribute to more persecutions.^[63]

 

 

 

 

 

 

 

 

 

 

 

 

THE SOUTH AMERICAN SEA LION

 

The South American sea lion (Otaria flavescens, formerly Otaria byronia), also called the southern sea lion and the Patagonian sea lion, is a sea lion found on the western and southeastern coasts of South America. It is the only member of the genus Otaria. The species is highly sexually dimorphic. Males have a large head and prominent mane. They mainly feed on fish and cephalopods and haul out on sand, gravel, rocky, or pebble beaches. In most populations, breeding males are both territorial and harem holding; they establish territories first and then try to herd females into them. The overall population of the species is considered stable, estimated at 265,000 animals.

The South American sea lion was classified as Otaria flavescens by George Shaw in 1800 and as Otaria byronia by Henri Marie Ducrotay de Blainville in 1820. The two nomenclatures were historically used interchangeably, but O. flavescens has become the preferred name.^[3][4] The species is also known by the common name "southern sea lion", although it is not preferred since the Australian sea lion and New Zealand sea lion also range in the Southern Hemisphere. Locally, it is known by several names, including león marino (sea lion) and lobo marino (sea wolf).^[3]

 

The South American sea lion is among the largest of and most sexually dimorphic of the eared seals. Males measure up to 3 m (9.8 ft) in length with a weight of 350 kg (770 lb) while females 

 reach a length 2 m (6 ft 7 in) and reach 150 kg (330 lb) in weight. Pups are born 0.86 m (2 ft 10 in) long and weigh 12–15 kg (26–

 

33 lb). Size differences between the sexes exists in both newborns and juveniles.^[3]

 

Adult males have large heads with short, upturned snouts and long manes which reach the shoulders.^[5] The fur is mainly brownish with adult males being dark brown and females being nearly yellowish. Pups are born black but become reddish-brown after their first molt.^[3]

 

 

The South American sea lion is found along the coasts and offshore islands of South America, from Peru south to Cape Horn and then north to southern Brazil.^[5][3] Notable breeding colonies include Lobos Island, Uruguay; Peninsula Valdes, Argentina; Beagle Channel, and the Falkland Islands. Some 

 

individuals wander as far north as southern Ecuador, although apparently they never bred there.^[5] However, the movement ecology of South American sea lions remains poorly understood, although biologging studies in recent years have advanced our understanding of their at-sea movements at some breeding locations.^[6][7][8][9] There is no evidence of a winter migration of sea lions from the Falkland Islands.^[10]

 

South American sea lions breed on beaches made of sand, gravel, rocky, or pebble. They can also be seen on flat, rocky cliffs with tidepools. Sea lion colonies tend to be small and scattered, especially on rocky beaches. The colonies make spaces between each individual when the weather is warm and sunny.^[5]

 

 

South American sea lions consume numerous species of fishes, including Argentine hake and anchovies. They also eat cephalopods, such as shortfin squid, Patagonian squid, and octopus.^[5] They have even been observed preying on penguins, pelicans, and young South American fur seals.^[11] South American sea 

 

lions may forage at the ocean floor for slow-moving prey or hunt schooling prey in groups, depending on the area. When captured, the prey is shaken violently and torn apart.^[5] South American sea lions have been recorded to take advantage of the hunting efforts of dusky dolphins.^[12] The sea lions themselves are preyed on by orcas and sharks; at Peninsula Valdes, orcas will beach themselves and grab sea lions near shore.^[3]

 

Mating occurs between December and February. Males arrive first to establish and defend territories, but then switch to defending females when they arrive. Estrus in females usually begins 6 days after the birth of a pup and soon after the copulations start with a peak in 

 

 

 

January. A male aggressively herds females in his territory and defends from both neighbors and intruders. On rocky beaches, males establish territories where females go to cool off, 

 

 keeping them until estrous. On cobble or sandy beaches, males have territories near the surf and monopolize females trying to get access to the sea. The number of actual fights between males depends on the number of females in heat. The earlier a male arrives at the site, the longer his tenure will be and the more copulations he will achieve. Males are usually able to keep around three females in their harems, but some have as many as 18.^[13][5]

During the breeding season, males that fail to secure territories and harems, most often subadults, will cause group raids in an attempt to change the status quo and gain access to the females. Group raids are more common on sandy beaches than rocky ones. These raids cause chaos in the breeding harems, often 

 

 splitting mothers from their young. The resident males try to fight off the raiders and keep all the females in their territorial boundaries. Raiders are often unsuccessful in securing a female, but some are able to capture some females or even stay in the breeding area with one or more females. Sometimes, an invading 

 

male abducts pups, possibly as an attempt to control the females. They also take pups as substitutes for mature females. Subadults herd their captured pups and prevent them from escaping, much like adult 

 

 males do to females. A pup may be mounted by its abductor, but intromission does not occur. While abducting pups does not give males immediate reproductive benefits, these males may gain experience in controlling females. Pups are sometimes severely injured or killed during abductions.^[14][15]

 

 

Despite being mostly a harem-territorial species, one population in Peru has been recorded having a lek-like breeding system. Here, with its longer ratio of males in comparison to females, the males cluster together and display and try to attract females while allowing then to move freely. The warmer climate also makes the females move constantly to the water, further making the traditional mating system difficult to maintain. The group raids that exist in temperate populations are virtually non-existent here.^[16]

Female sea lion and pup

Sea lion mothers remain with their newborn pups for nearly a week before making a routine of taking three-day foraging trips and coming back to nurse the pups.^[13][5] They act aggressively to other females 

 that come close to their pups, as well as alien pups that try to get milk from them.^[17] Pups first enter the water at about four weeks and are weaned at about 12 months. This is normally when the mother gives birth to a new pup. Pups gradually spend more time in the nearshore surf and develop swimming skills.^[5]

South American sea lions are observed to make various vocalizations and calls which differ between sexes and ages. Adult males make high-pitched calls during aggressive interactions, barks and growls when establishing territories, growls when interacting with females, and exhalations after antagonistic 

 

 encounters. Females with pups make a mother primary call when interacting with their pups, and grunts during aggressive encounters with other females. Pups make pup primary calls. Some of those vocalizations and acoustic features may support individuality.^[18]

 

The Moche people of ancient Peru worshipped the sea and its animals. They often depicted South American sea lions in their 

 

art.^[19] Two statues of this species are the symbol of the city of Mar del Plata.^[20]

Indigenous peoples of South America exploited this species for millennia and by Europeans around the 16th century.^[21] The hunting has since gone down and the species is no longer threatened. The species is 

 

protected in most of its range. Numerous reserves and protected areas at rookeries and haul-out sites exist for the sea lions. Despite this, protection regulations are not effectively enforced in much of animals' range.^[1]

 

 

The overall population of sea lions is considered stable; the estimate is 265,000 animals. They are declining in the Falkland Islands, and in Argentina Patagonia, but are increasing in Chile and Uruguay.^[1] Many sea lions of the Peruvian population died in the 1997/1998 el Niño.^[1][22] They still are killed due to their habits of stealing fish and damaging fishing nets.^[1]

 

 

 

 

 South American sea lion range