Ring-tailed lemur
The ring-tailed lemur is a medium- to larger-sized strepsirrhine primate and the most internationally recognized lemur species, owing to its long, black-and-white, ringed tail. It belongs to Lemuridae, one of five lemur families, and is the only member of the Lemur genus. Like all lemurs, it is endemic to the island of Madagascar, where it is endangered. Known locally in Malagasy as maky or hira, it ranges from gallery forests to spiny scrub in the southern regions of the island. It is omnivorous, as well as the most adapted to living terrestrially of the extant lemurs.
The ring-tailed lemur is highly social, living in groups—known as "troops"—of up to 30 individuals. It is also a female-dominant species, a commonality among lemurs. To keep warm and reaffirm social bonds, groups will huddle together. Mutual grooming is another vital aspect of lemur socialization, reaffirming social and familial connections, while also helping rid each other of any potential insects. Ring-tailed lemurs are strictly diurnal, being active exclusively during daylight hours. Due to this lifestyle, they also sunbathe; the lemurs can be observed sitting upright on their tails, exposing their soft, white belly fur towards the sun. They will often also have their palms open and eyes gently closed. Like other lemurs, this species relies strongly on their sense of smell, and territorial marking, with scent glands, provides communication signals throughout a group's home range. The glands are located near the eyes, as well as near the anus. The males perform a unique scent-marking behavior called spur-marking and will participate in stink fights by dousing their tails with their pheromones and "wafting" them at opponents. Additionally, lemurs of both sexes will scent-mark trees, logs, rocks or other objects by simply rubbing their faces and bodies onto it, not unlike a domestic cat.
As one of the most vocal primates, the ring-tailed lemur uses numerous vocalizations, including calling for group cohesion and predator alarm calls. Experiments have shown that the ring-tailed lemur, despite the lack of a large brain, can organize sequences, understand basic arithmetic operations, and preferentially select tools based on functional qualities.
Despite adapting to and breeding easily under captive care, the wild population of ring-tailed lemur is listed as endangered by the IUCN Red List, due to habitat destruction, local hunting for bushmeat and the exotic pet trade. As of early 2017, the population in the wild is believed to have lowered to as few as 2,000 individuals due to these reasons, making them far more critically endangered. Local Malagasy farmers and logging industries frequently make use of slash and burn deforestation techniques, with smoke being visible on the horizon on most days in Madagascar, in an effort to accommodate livestock and to cultivate larger fields of crops.
Etymology
Although the term "lemur" was first intended for slender lorises, it was soon limited to the endemic Malagasy primates, which have been known as "lemurs" ever since. The name derives from the Latin term lemures, which refers to specters or ghosts that were exorcised during the Lemuria festival of ancient Rome. According to Carl Linnaeus's own explanation, the name was selected because of the nocturnal activity and slow movements of the slender loris. Being familiar with the works of Virgil and Ovid and seeing an analogy that fit with his naming scheme, Linnaeus adapted the term "lemur" for these nocturnal primates. However, it has been commonly and falsely assumed that Linnaeus was referring to the ghost-like appearance, reflective eyes, and ghostly cries of lemurs. It has also been speculated that Linnaeus may also have known that some Malagasy people have held legends that lemurs are the souls of their ancestors, but this is unlikely given that the name was selected for slender lorises from India. The species name, catta, refers to the ring-tailed lemur's cat-like appearance. Its purring vocalization is similar to that of the domestic cat.Following Linnaeus's species description, the common name "ring-tailed maucauco" was first penned in 1771 by Welsh naturalist Thomas Pennant, who noted its characteristic long, banded tail. The now universal English name "ring-tailed lemur" was first used by George Shaw in his illustrated scientific publication covering the Leverian collection, which was published between 1792 and 1796.
Evolutionary history
All mammalian fossils from Madagascar come from recent times. Thus, little is known about the evolution of the ring-tailed lemur, let alone the rest of the lemur clade, which comprises the entire endemic primate population of the island. However, chromosomal and molecular evidence suggest that lemurs are more closely related to each other than to other strepsirrhine primates. For this to have happened, it is thought that a very small ancestral population came to Madagascar via a single rafting event between 50 and 80 million years ago. Subsequent evolutionary radiation and speciation has created the diversity of Malagasy lemurs seen today.According to analysis of amino acid sequences, the branching of the family Lemuridae has been dated to 26.1 ±3.3 mya while rRNA sequences of mtDNA place the split at 24.9 ±3.6 mya. The ruffed lemurs are the first genus to split away in the family, a view that is further supported by analysis of DNA sequences and karyotypes. Additionally, Molecular data suggests a deep genetic divergence and sister group relationship between the true lemurs and the other two genera: Lemur and Hapalemur.
The ring-tailed lemur is thought to share closer affinities to the bamboo lemurs of the genus Hapalemur than to the other two genera in its family. This has been supported by comparisons in communication, chromosomes, genetics, and several morphological traits, such as scent gland similarities. However, other data concerning immunology and other morphological traits fail to support this close relationship. For example, Hapalemur species have short snouts, while the ring-tailed lemur and the rest of Lemuridae have long snouts. However, differences in the relationship between the orbit and the muzzle suggest that the ring-tailed lemur and the true lemurs evolved their elongated faces independently.
The relationship between the ring-tailed lemur and bamboo lemurs is the least understood. Molecular analysis suggests that either the bamboo lemurs diverged from the ring-tailed lemur, making the group monophyletic and supporting the current two-genera taxonomy, or that the ring-tailed lemur is nested in with the bamboo lemurs, requiring Hapalemur simus to be split off into its own genus, Prolemur.
The karyotype of the ring-tailed lemur has 56 chromosomes, of which four are metacentric, four are submetacentric, and 46 are acrocentric. The X chromosome is metacentric and the Y chromosome is acrocentric.
Taxonomic classification
Linnaeus first used the genus name Lemur to describe "Lemur tardigradus" in his 1754 catalog of the Museum of King Adolf Frederick. In 1758, his 10th edition of Systema Naturae listed the genus Lemur with three included species, only one of which is still considered to be a lemur while another is no longer considered to be a primate. These species include: Lemur tardigradus, Lemur catta, and Lemur volans. In 1911, Oldfield Thomas made Lemur catta the type species for the genus, despite the term initially being used to describe lorises. On January 10, 1929, the International Commission on Zoological Nomenclature formalized this decision in its publication of Opinion 122.The ring-tailed lemur shares many similarities with ruffed lemurs and true lemurs, and its skeleton is nearly indistinguishable from that of the true lemurs. Consequently, the three genera were once grouped together in the genus Lemur and more recently are sometimes referred to as subfamily Lemurinae. However, ruffed lemurs were reassigned to the genus Varecia in 1962, and due to similarities between the ring-tailed lemur and the bamboo lemurs, particularly in regards to molecular evidence and scent glands similarities, the true lemurs were moved to the genus Eulemur by Yves Rumpler and Elwyn L. Simons as well as Colin Groves and Robert H. Eaglen. In 1991, Ian Tattersall and Jeffrey H. Schwartz reviewed the evidence and came to a different conclusion, instead favoring to return the members of Eulemur and Varecia to the genus Lemur. However, this view was not widely accepted and the genus Lemur remained monotypic, containing only the ring-tailed lemur. Because the differences in molecular data are so minute between the ring-tailed lemur and both genera of bamboo lemurs, it has been suggested that all three genera be merged.
Because of the difficulty in discerning the relationships within family Lemuridae, not all authorities agree on the taxonomy, although the majority of the primatological community favors the current classification.
| Taxonomy of family Lemuridae | Phylogeny of family Lemuridae |
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In 1996, researchers Steven Goodman and Olivier Langrand suggested that the ring-tailed lemur may demonstrate regional variations, particularly a high mountain population at Andringitra Massif that has a thicker coat, lighter coloration, and variations in its tail rings. In 2001, primatologist Colin Groves concluded that this does not represent a locally occurring subspecies. This decision was later supported by further fieldwork that showed that the differences fell within the normal range of variation for the species. The thicker coat was considered a local adaptation to extreme low temperatures in the region, and the fading of the fur was attributed to increased exposure to solar radiation. Additional genetic studies in 2000 further supported the conclusion that population did not vary significantly from the other ring-tailed lemur populations on the island.