Primatology.net

On April 13, 2011, The Maryland Zoo in Baltimore announced the birth of an Endangered Coquerel’s Sifaka (Propithecus coquereli) making it one of only 50 individuals found in accredited institutions in the United States.

Coquerel-Sifaka at the Maryland Zoo in Baltimore, Photo: Kristin Abt

Read the press release for more information!

The Duke Lemur Center manages the United States’ Coquerel’s Sifaka population and provides more information about the species: Coquerel’s Sifaka

By: Kristin Abt

A recent article in the journal, Zoo Biology, discusses the current lack of gum enrichment for certain primate species in a captive setting that is in contrast to their wild behavior. Huber and Lewis (2011) surveyed zoos at an international scale to assess the occurrence and methods of “gum-based enrichment.”

Patas Monkey at Woodland Park Zoo (Photo: Kristin Abt)

Golden Lion Tamarin at National Zoo (Photo: Kristin Abt)

They identify numerous primates that feed on gums in varying amounts in the wild, including galagos and lorises, marmosets and tamarins, and members of Cercopithecinae.  Because enrichment aims to promote species-typical behaviors in a non-natural environment, the items that are offered should be primarily selected based on whether or not they contribute to this aim.

This study obtained responses from 46 zoos, 27 of which feed gum to at least some of their primates. The greatest disparity between wild gum-feeding and captive gum-provisioning was for cercopithecines. They identify patas monkeys as obligate gumnivores; therefore, they specifically highlight the need for the development of enrichment programs utilizing gum for this species. Also, they highlight the need to provide enrichment devices that simulate how primates feed on gum in the wild as opposed to free-feeding in dishes.

Patas Monkey Exhibit (Photo: Kristin Abt)

Huber and Lewis (2011) take a focused approach to assessing an area of enrichment within zoos that can have a marked management impact. This study shows the value of applied research to enhance the ability of zoos and other facilities to care for their collections in a manner more representative of the wild experience.

Reference:

Huber, H. F. & Lewis, K. P. (2011). “An assessment of gum-based environmental enrichment for captive gumnivorous primates.” Zoo Biology 30: 71-78.

Orangutan at Sepilok (Photo: Kristin Abt)

A recent article “Fostering Appropriate Behavior in Rehabilitant Orangutans (Pongo pygmaeus)” published online in the International Journal of Primatology discusses research on the behavior of rehabilitant orangutans (Pongo pygmaeus and P. abelii) at the Orangutan Care and Quarantine Centre in Pangkalan Bun, Kalimantan (Indonesian Borneo). Much past research has focused on postrelease behavior of rehabilitated orangutans and on the behavior of wild individuals; therefore, this research is especially timely and useful for the number of centers currently attempting to rehabilitate the ever-increasing number of displaced great apes and other fauna (Descovich et al., 2011).

Orangutans (n=40) in this study included males and females, mass classes ranging from 5 to 25 kg, and good, moderate, and poor health distinctions. Individuals were observed continuously for a period of 5 hours during 3 separate forest excursions each.  A number of behaviors relevant to postrelease success in the forest habitat were recorded (type of locomotion, social behavior, such as play, human caretaker interaction, point of height in tree or on ground, feeding and food choice, grooming, etc.).

Results from this study showed that rehabilitant individuals’ masses were associated with the amount of time spent at the centre. Authors note this finding as a result of the early age of admittance to the centre for most individuals. Further, orangutans in better health spent an increased amount of time consuming food and less time resting than other categories. In terms of locomotion (>30% of overall time), quadrupedal movement in trees was the dominant method (again, with orangutans in better health doing so more often). Individuals who had been at the Care Centre longer spent more time on the ground rather than swinging or other locomotion. As the day in which focal individuals were observed continued, human interaction increased.

As rehabilitation of orphaned individuals is a component of the long-term species survival of orangutans, research regarding the behavior of these individuals is important for increasing the chance of postrelease survival and success. Additionally, as their habitat is lost as a result of a number of conservation threats, land protection is necessary to provide habitat in which the released individuals and their wild conspecifics can live.

Reference

Descovich, K. A., Galdikas, B. M., Tribe, A., Lisle, A., & Phillips, C. J. 2011. Fostering appropriate behavior in rehabilitant orangutans (Pongo pygmaeus). International Journal of Primatology. doi:10.1007/s10764-011-9491-1

Orangutan Foundation International (a 501(c)3 nonprofit organization) supports the work of the Orangutan Care and Quarantine Centre and other crucial efforts to promote orangutan conservation, including land protection, research, and education. Visit www.orangutan.org to donate directly to OFI. If you would like to donate items specifically to enhance the lives of individuals at the Care Centre, visit this wishlist to select items that orangutans, such as those in this study, will greatly benefit from. If you would like to learn more, look for the upcoming IMAX© movie Born to Be Wild to be released in theaters April 8, 2011.

Woodland Park Zoo Lion-tailed Macaque (Photo: Kristin Abt)

By: Kristin Abt

The Lion-tailed Macaque (Macaca silenus) is an endangered cercopithecine primate native to the Western Ghats region of India, described as one of the primary hotspots of biodiversity in the world (Kumara & Singh, 2004).  IUCN (2010) estimates a mere 2,500 mature individuals with a total population size of 4,000 individuals.  Furthermore, these monkeys (LTMs) exist in an estimated 47 subpopulations in 7 locations.  Their serious status merits continuing intense and collaborative research on their demographics, current pressures, and the effects of habitat fragmentation, which appears to be the primary concern for their long-term survival in the wild.

Ecology and Distribution

These Old World monkeys have cheek pouches with simple stomachs, long, non-prehensile tails, an opposable hallux and pollex, hardened ischial callosities, and close, downward facing nostrils.  They are diurnal with complex, matrilineal social systems normally with one adult male and one subadult male to multiple females and their offspring.  Males disperse and females display estrus swellings to advertise their reproductive status.  They have an average group size of 18 with a range of 7 to 40 individuals (Umapathy & Kumar, 2000b).  Compared to other macaque species, Umapathy and Kumar point out that they have a slower life history with females reproducing first at 6.6 years and having a birth rate of 0.31 infants/female/year thereafter.  This overall low prolificacy with delayed sexual maturity, long interbirth interval, and low population turnover presents an additional challenge when groups must respond to external survival pressures.

The LTM differs from other macaque species additionally through its primarily arboreal nature.  Menon and Poirier (1996) emphasize this characteristic through the documentation of 3 falls and one subsequent death from tree gaps.  In places with incontiguous canopy cover, individuals exhibited a strong preference to exert considerable effort to cross large holes in the canopy without descending to the ground.  Ramachandran and Joseph (2000) discuss the conservation and sustainability implications of this in that LTMs failed to range into adjacent areas disrupted by fire or eucalypt and teak plantations in order to exhaust nearby resources in neighboring forest fragments.

Individuals are found only in the Western Ghats region in the three states of Kerala, Karnataka, and Tamil Nadu and have been studied extensively in such national and private evergreen forests as Silent Valley in the Palghat district (Ramachandran & Joseph, 2000), the Indira Gandhi Wildlife Sanctuary in Anamalai Hills (Umapathy & Kumar, 2000a & b), Brahmagiri-Makut and Sirsi-Honnovara (Kumara and Singh 2004), the Puthuthotam Cardamom Forest (Menon & Poirier, 1996), and the Kudremukh Forest Complex (Kumara & Singh, 2008).  Within these locations, it has been found that the LTMs prefer habitat primarily between 300m asl – 900m asl (Kumara & Singh, 2008).  It is estimated that almost 40% of the remaining population exist as small groups found in isolated, highly fragmented forests in these areas (Umapathy & Kumar, 2000a).  As one goes from South to North within their range, group size has been shown to increase (Kumara & Singh, 2004).

Woodland Park Zoo Exhibit for Lion-tailed Macaques (Photo:Kristin Abt)

Within their habitat, LTMs serve as “one of the most important habitat specialist primates in India” (Ramachandran & Joseph, 2000).  Sushma and Singh (2006) found that compared to other arboreal mammals, such as bonnet macaques (Macaca radiata), Nilgiri langurs (Semnopithecus johnii), and the Indian giant squirrel (Ratufa indica), LTMs have the narrowest niche breadth with some overlap with bonnet macaques, which indicates a degree of competition where these animals must coexist.  Ramachandran and Joseph (2000) point out that they seldom range outside of their evergreen forest even into the deciduous areas.  They also reported that LTMs feed primarily (91%) on plant matter with the remainder consisting of invertebrates, which is a higher amount than other macaque species (Sushma & Singh, 2006).  Ramachandran & Joseph (2000) found that they formed significant associations with 6 major tree species, especially Cullenia.  These are needed in the proper abundance in order to sustain the primates; however, some flexibility is present.  Menon and Poirier (1996) note that, in times of food scarcity, individuals supplement their diet with Artocarpus and Coffea trees in nearby forested plantations. Because they are highly frugivorous and consume large amounts of figs (Sushma & Singh, 2006), they must range significant distances in order to find sufficient food for the group.  Fruit, as a seasonal and patchy resource, offers a lot of carbohydrates, but not a good amount of protein.  As a result, invertebrates comprise a relatively large amount of their diet in order to provide the necessary nutrition for successful reproduction (Umapathy & Kumar, 2000a). Juveniles spend a significantly larger amount of time feeding on these, suggesting their importance for proper growth and development, as well.

Western Ghats, India Map from cepf.net

Conservation Threats due to Habitat Fragmentation

When primate groups are found in highly fragmented habitat, this presents serious survival pressures for themselves and for those individuals in neighboring forests without the opportunity for gene flow.  McGarigal and Cushman (2002) define habitat fragmentation as a “landscape level process in which a specific habitat is progressively subdivided into smaller and more isolated fragments.”  They further discuss how it encompasses a change in landscape composition, structure, and function.  Because habitat fragmentation, along with habitat loss, is considered to be one of the main influences causing the incredible mass extinction of species that is currently occurring, studying the effects of this in order to produce urgent and important management strategies is paramount.

Thus far, a number of studies of the LTM have discovered relevant consequences to the habitat fragmentation continually occurring within their range.  In reference to the demographics of social groups, the effects of habitat fragmentation have been to significantly change the composition naturally found in contiguous and undisturbed sections of forest.  Specifically, Umapathy and Kumar (2000b) found near significance with smaller fragments containing larger group sizes compared to larger fragments.  Also, it appears that there is more likely to be two adult males in a social group of a small fragment than the typical one male: multiple females found in larger fragment sizes.  Significantly, there is a positive correlation between fragment size and the number of immatures and birth rate.  The authors cite possible factors for this as increased predation pressures and resource shortages.  Kumara and Singh (2004) classified health of a population by a high overall presence of groups with the modal group size, favorable sex ratio, and a large percentage of immature individuals; therefore, the findings from the previous study provide further support to their criteria as valid to use when investigating the demographics of LTMs in fragmented areas.

Studies have also investigated how vegetation status in relation to level of fragmentation affects these primates.  Umapathy and Kumar (2000a) found that individuals spent significantly less time feeding on invertebrates, a key component to their diet, in smaller fragments.  Additionally, the least disturbed fragments contained the highest plant abundance.  In areas with colonized species, such as mangos and guava, the macaques added these to their diet, which might slightly compensate for the loss in space and flora diversity; however, it could also contribute to human-wildlife conflict.  Furthermore, these researchers (2000b) also demonstrated a positive correlation between the quality of vegetation and the amount of fragmentation.

Along with demographic and dietary changes, significant changes occur in disturbed populations with respect to the groups’ overall behaviors and activity patterns.  Menon and Poirier (1996) studied individuals in a private forest that experienced selective logging and clearing for planting on the floor and found that the primates used the ground often for ranging and foraging out of necessity, but still much preferred the trees – even when travelling in such a manner presented serious and mortal danger due to the lack of sufficient canopy continuity.  They were also forced to cross roads and raid fruit in neighboring plantations, which resulted in human-wildlife conflict and deterrence measures implemented.  Furthermore, the individuals needed to increase their time ranging, which seriously impacted their ability to feed and engage in necessary social behaviors.  Especially relevant to small, isolated populations is the inability to disperse naturally, which Debinski and Holt (2000) discuss and, consequently, suggest corridors for landscape connectivity, especially for highly mobile animals.  Without proper gene flow and the opportunities for appropriate social groups to form, the long-term survival of this species is severely threatened, which is already evidenced by the results of lower numbers of juveniles in these fragmented groups.

In addition to the restriction of available habitat and isolation of existing groups, human-wildlife conflict has placed significant pressure on their survival.  Along with plantations cultivated for teak and eucalypt and areas that are clear felled for tea and coffee, humans also use the forest areas for wood gathering, logging, and hunting of the LTMs and other fauna (Kumara & Singh, 2000b; Menon & Poirier, 1996).  Fragments also increase the likelihood of the macaques coming into human contact and the likelihood that humans will disturb the forest.

Conclusions

As with so many conservation stories, this one can greatly benefit from increased attention, education, and priority at numerous levels. Over recent years, the LTM has featured less prominently in North American zoo collections despite its endangered status, declining populations, charismatic appearance, and active nature (Association of Zoos and Aquariums, 1998). Additionally, few conservation and education efforts are currently in place to support its population (AZA, 1998). While research into its populations and its behavioral ecology are important to further understand the species, additional efforts to increase gene flow between populations, protect its forest habitat, and address conflicts with agriculture are needed for this macaque species to persist.

References

Association of Zoos and Aquariums. 1998. Lion-tailed macaque 98 fact sheet. Retrieved February 8, 2011, from Web site: http://www.nagonline.net/Fact%20Sheet%20pdf/AZA%20-%20Lion-Tailed%20Macaque%20 Species%20Survival%20Plan.pdf

Debinski, D. M. and R. D. Holt. 2000. A survey and overview of habitat fragmentation experiments. Conservation Biology 14: 342–355.

IUCN.  2010 IUCN Red List of Threatened Species.  Retrieved February 8, 2011, from Web site: http://www.iucnredlist.org/details/12559

Kumara, H. N. and M. Singh. 2004. Distribution and abundance of primates in rain forests of the Western Ghats, Karnataka, India and the conservation of Macaca silenus. International Journal of Primatology 25: 1001–1018.

Kumara, H. N. and V. R. Singh. 2008. Status of Macaca silenus in the Kudremukh Forest Complex, Karnataka, India. International Journal of Primatology 29: 773–781.

McGarigal, K. and S. A. Cushman. 2002. Comparative evaluation of experimental approaches to the study of habitat fragmentation effects. Ecological Applications 12: 335–345.

Menon, S. and F. E. Poirier. 1996. Lion-tailed Macaques (Macaca silenus) in a disturbed forest fragment: Activity patterns and time budget. International Journal of Primatology 17: 969–985.

Ramachandran, K. K. and G. K. Joseph. 2000. Habitat utilization of lion-tailed macaque (Macaca silenus) in Silent Valley National Park, Kerala, India. Primate Report 58: 17–25.

Sushma, H. S. and M. Singh. 2006. Resource partitioning and interspecific interactions among sympatric rain forest arboreal mammals of the Western Ghats, India. Behavioral Ecology 17: 479–490.

Umapathy, G. and A. Kumar. 2000a. Impacts of the habitat fragmentation on time budget and feeding ecology of lion-tailed macaque (Macaca silenus) in rain forest fragments of Anamalai Hills, South India. Primate Report 58: 67–82.

Umapathy, G. and A. Kumar. 2000b. The demography of the Lion-tailed Macaque (Macaca silenus) in rain forest fragments in the Anamalai Hills, South India. Primates 41: 119–126.

By: Kristin Abt

Recently published online in the International Journal of Primatology, an article by Humle, Colin, Laurans, and Raballand (2010) discusses the release of a group of 12 chimpanzeees into the High Niger National Park in Guinea, West Africa. Through the efforts of the Chimpanzee Conservation Center, 9 chimpanzees remain in natural habitat at the time of publication. The conservation benefits of this substantial undertaking are numerous:

• While the park already has a viable population of chimpanzees, this effort adds reproductively mature individuals and genetic material to the endangered wild population.
• Additionally, with over 1000 chimpanzees in sanctuaries and other facilities rather than in the wild, the need to address their long-term management is acute. Not only is the individual welfare of the released chimpanzees enhanced, this scientific study of the release process will also aid conservation practitioners in the implementation of future chimpanzee rehabilitation.
• As the authors point out, the conservation status and role of the release area is promoted to the government and general public, which will hopefully bolster its future capacity to serve as suitable habitat for many species.

Previous reintroduction efforts have led to the adoption of an overall chimpanzee reintroduction plan that emphasizes adequate rehabilitation training for individuals and substantial monitoring following release. In order to determine an appropriate area for release, the authors cite numerous components, including habitat suitability (food, other resources, terrain, etc.), level of and proximity to human pressures, and the overall ability of chimpanzees to thrive in the absence of human involvement. Further, in order to monitor the activities of the chimpanzees, researchers used radiotracking collars on released individuals.

Chimpanzee (Photo: Kristin Abt)

The release site was chosen in part due to its strict protection as a core area within the park and its minimal roads. The demographics of the released individuals were 6 males and 6 females ranging from 8 to 20 years of age. Information included in the article details the social familiarity of the group, survival skills possessed by the individuals, and the number of years each had access to formative “bush-outings” with caretakers and expansive, naturalistic enclosures. Additionally, the researchers verified the genetic appropriateness of the subspecies (Pan troglodytes verus) and the overall health of each chimpanzee. The article also provides a 20 month timeline of events relevant to the release process including group dynamics, deaths, births, and sightings with wild chimpanzees.

Humle et al (2010) discusses the ranging patterns and habitat use of the released chimpanzees to obtain an overall picture of their behavior compared to typical wild chimpanzees in the area. Released males traveled significantly further than released females as measured by maximum mean distance travelled. They also remained significantly further from the release site than the females. Overall, the chimpanzees preferred forested areas over open space. Within the mixed forest-savanna habitat where the chimpanzees were released, the individuals remain independent of human provisioning. Additionally, two chimpanzees have been born to released females. Humle et al (2010) suggests that part of the success of the released chimpanzees could be due to the lower population densities of wild chimpanzees in the mixed habitat type along with their relatively larger ranges.

A number of agencies and professionals will ultimately contribute to the conservation efforts of a given species, as noted by the authors. This paper attempted to combine data on behavior, ecology, conservation, and wildlife management in order to approach the multi-faceted undertaking of chimpanzee rehabilitation. As with many conservation projects, communication and an interdisciplinary approach are needed to successfully achieve targeted goals.

The Chimpanzee Conservation Centre (CCC) is a member of the Pan African Sanctuary Alliance (PASA) that aims to promote the welfare and conservation of primates in African countries. It unites sanctuaries together to train professionals at the facilities about animal management, veterinary care, and education. PASA accepts donations at its website to continue its primate care and conservation efforts.

Reference

Humle, T., Colin, C., Laurans, M., & Raballand, E. (2010). Group release of sanctuary chimpanzees (Pan troglodytes) in the Haut Niger National Park, Guinea, West Africa: Ranging patterns and lessons so far. International Journal of Primatology. doi: 10.1007/s10764-010-9482-7

The study of conservation biology, and its oft-times competitor – urbanization, is increasingly relevant to the study of primatology. As a species, long-tailed macaques demonstrate a number of conflicts and potential implications of the urbanization occurring in primate-habitat countries. The long-tailed macaque (Macaca fascicularis) is the third-most common primate in the world with an extensive range across Southeast Asia covering Timor and the Philippines to the Southeast of Bangladesh (Richard, Goldstein, & Dewar, 1989). Although they are common relative to other primate species and listed as least concern by the IUCN, scientists recognize that their range and population status is declining due to habitat loss and degradation and exportation for the biomedical industry (Eudey, 2008). Whole groups are cultivated in Cambodia for trapping and sale for pharmaceutical testing based on demand from China and the United States while other anthropogenic factors, such as shipbuilding and shrimp farming negatively impact populations in Bangladesh (Eudey, 2008). They have also been introduced to areas outside their native range, including to the island of Mauritius and to China for use in medicine and consumption (Eudey, 2008; Richard, Goldstein, & Dewar, 1989).

Macaque (Photo: Kristin Abt)

While macaques are able to utilize a variety of human habitats, Malaivijitnond and Hamada (2008) suggest that anthropogenic land-use change has forced these animals to coexist in human-dominated landscapes. Long-tailed macaques are naturally found in low elevation habitats, including, seashores, swamp and mangrove forests, and river banks (Eudey, 2008). Studies have found, however, that long-tailed macaques prefer secondary, disturbed forests to the primary forests that most other primate species prefer (Richard, Goldstein, & Dewar, 1989). Macaques are commonly seen and encouraged in monkey parks, temples, monasteries, city and forest parks, and restaurants, often with individuals released as pets incorporated into the urban troops (Malaivijitnond & Hamada, 2008). This study based in Thailand found that groups averaged two-hundred monkeys per location with five locations containing upwards of one thousand individuals in a single group, including numerous subspecies and hybridized animals. These groups are locally overcrowded, which exacerbates human-wildlife conflict, especially in dry seasons and limited food supply (Malaivijitnond & Hamada, 2008). An extreme example of such conflict possible in an urban environment occurred in Malaysia where a suspected long-tailed macaque approached a house, potentially attracted by the female pet monkey, and grabbed a baby that it later dropped to the ground when it became alarmed. The child did not survive the incident and the monkey was found and shot (“Monkey snatches,” 2010).

Aggressive encounters with macaques are common in urban areas and some countries hire guards in public places to chase the animals away (Richard, Goldstein, & Dewar, 1989). Unintentionally, humans contribute to the problem by leaving garbage for them to raid (Eudey, 2008). In many cases, humans actively promote their presence for spiritual and entertainment purposes by provisioning food for the macaques, including banana, papaya, watermelon, mango, rambutan, pineapple, and coconut (Malaivijitnond & Hamada, 2008). These authors noted that local villagers in Thailand will hold “feeding parties” for the macaques and stop their cars to allow troops to cross roads, yet need to protect their buildings and houses with metal and protective guarding from the damage caused by macaques. There is also the potential for zoonotic disease transmission, including the potentially fatal herpes B simplex virus, from macaques to people. Long-tailed macaques will also commonly raid human crops, including rubber fruits, rice shoots, corn, and beans, causing some to label them as pest or “weed” species (Richard, Goldstein, & Dewar, 1989). The monkeys have been seen raiding palm oil plantations in Borneo, as well (personal observation).

Long-tailed macaques exist in the absence of humans on forest edges with suitable access to fruits and crustaceans; however, the urban environment facilitates their feeding and reproduction potential by increasing group sizes and decreasing their need to forage and seek wild habitat. Humans both promote macaque populations through provisioning and protection in some habitats and hinder through habitat fragmentation, exportation for research, human consumption, and the pet-trade.

References

Eudey, A. A. (2008). “The crab-eating macaque (Macaca fascicularis): Widespread and rapidly declining.” Primate Conservation, 23, 129-132.

Malaivijitnond, S., & Hamada, Y. (2008). Current situation and status of long-tailed macaques (Macaca fascicularis) in Thailand. The Natural History Journal of Chulalongkorn University, 8(2), 185-204.

“Monkey snatches, kills baby in Malaysia.” October 7, 2010. My Fox DC. Retrieved from www.myfoxdc.com.

Richard, A. F., Goldstein, S. J., & Dewar, R. E. (1989). “Weed macaques: The evolutionary implications of macaque feeding ecology.” International Journal of Primatology, 10(6), 569-594.