The Crab-eating
Macaque (Macaca fascicularis) is a primarily arboreal macaque native to
Southeast Asia. It is also called the Cynomolgus Monkey, Philippine
Monkey and the Long-tailed Macaque.The scientific name of the
Crab-eating Macaque is Macaca fascicularis. Macaca comes from the
Portuguese word macaco, which was picked up from makaku, a Fiot (West
African language) word (kaku means 'monkey' in Fiot). Fascicularis is
Latin for 'a small band'. Sir Thomas Raffles, who gave the animal its
scientific name in 1821, did not specify what he meant by the use of
this word although it is presumed it had something to do with his
observation of the animal's colour.
The common name of this animal varies. It is commonly referred to as
the Long-tailed Macaque because the tail of this macaque is usually
about the same length as its body and because its long tail
distinguishes it from most other macaques. The species is also commonly
known as the Crab-eating Macaque. Another common name for M.
fascicularis is the Cynomolgous Monkey, which literally means "dog-milker"
monkey, which is the name most commonly used for these animals in
laboratory settings. In Indonesia, M. fascicularis and other macaque
species are generically known as kera, possibly because of the
high-pitched alarm calls they give when in danger ("krra! krra!").
Subspecies
There is significant genetic diversity within the species and these
differences are classified into at least 10 subspecies:
* Crab-eating Macaque, Macaca fascicularis fascicularis
* Burmese Long-tailed Macaque, Macaca fascicularis aurea
* Nicobar Long-tailed Macaque, Macaca fascicularis umbrosa
* Dark-crowned Long-tailed Macaque, Macaca fascicularis atriceps
* Con Song Long-tailed Macaque, Macaca fascicularis condorensis
* Simeulue Long-tailed Macaque, Macaca fascicularis fusca
* Lasia Long-tailed Macaque, Macaca fascicularis lasiae
* Maratua Long-tailed Macaque, Macaca fascicularis tua
* Kemujan Long-tailed Macaque, Macaca fascicularis karimondjawae
* Philippine Long-tailed Macaque, Macaca fascicularis philippinensis
Physical characteristics
Depending on sub-species, the body length of the adult monkey is
38-55 centimetres (15-22 in) with comparably short arms and legs. The
tail is longer than the body, typically 40-65 cm (16-26 in). Males are
considerably larger than females, weighing 5-9 kilograms (11-20 lb)
compared to the 3-6 kg (7-13 lb) of female individuals.
Macaca fascicularis is a very social animal that lives in groups
anywhere from 5-60+ animals. These groups are multi-male groups,
normally containing 2-5 males and 2-3 times as many females. The number
of immature is usually comparative to the number of females. Their group
size often depends on the level of predation and availability of food.
Their groups are female-centred, as the females are philopatric (i.e.
remain in one place across generations) and the males move in and out of
these female-based groups. Males generally first emigrate from their
natal group at the age of 4-6. They will remain in a group up to four or
five years and thus will emigrate several times throughout their life.
These monkeys are highly despotic and have a strict dominance hierarchy.
Adult males rank higher than females. Female ranks are more stable than
males, as males from time-to-time will be defeated and lose rank.
High-ranked males generally are more successful at reproduction and
high-ranked females generally fare better at raising surviving
offspring. The females are organized into matrilines, which are the
female-based families consisting of the resident females and their
offspring. Matrilines are ranked and some families have greater social
power than others and this difference in rank is maintained over several
generations. Matrilineal overthrows rarely occur and when they do they
have severe consequences to the reproductive success of the defeated
matriline in the following year.
After a gestation period of 167-193 days, the female gives birth to
one infant. The infant's weight at birth is approximately 350 grams (12
oz). Infants are born with black fur and this fur will begin to turn to
a yellow-green, grey-green, or reddish-brown shade (depending on the
sub-species) after about three months of age. It is suggested this natal
coat indicates to others the status of the infant and other group
members treat infants with care and rush to their defence when
distressed. Newly immigrated males will sometimes commit infanticide on
infants not their own, and high-ranked females sometimes kidnap the
infants of lower-rank females. These kidnapping usually result in the
fatality of the infants, as the other female usually is not lactating.
Young juveniles stay with the mother and relatives mainly, and as male
juveniles get older they become more peripheral to the group. Here they
play together forming crucial bonds that may help them when the emigrate
from their natal group. Males that emigrate with a partner seems to be
more successful than those that move off alone. Young females on the
other hand stay in the centre of the group and become incorporated into
the matriline they were born into.
Results of a research shows that male Crab-eating Macaques will groom
females in order to get sex. The study found that a female has a greater
likelihood to engage in sexual activity with a male if he had recently
groomed her, compared to males who had not groomed her.
Diet
Although members of this species are often referred to as Crab-eating
Macaques, this name is something of a misnomer, since their diet is by
no means limited to crabs. Other food items are in fact far more common.
They are opportunistic omnivores, meaning they can and will eat a wide
variety of animals, plants, and other materials. Although fruits and
seeds make up 60 - 90% of the dietary intake, they also eat leaves,
flowers, roots and bark, and also prey on vertebrates (including bird
chicks and nesting female birds, lizards, frogs, fishes, et al.),
invertebrates, and bird eggs. Although the species is ecologically
well-adapted in its native range and poses no particular threat to the
overall populations of prey species, in areas where the Crab-eating
Macaque is non-native it can pose a substantial threat to biodiversity.
The Crab-eating Macaque is sometimes known as a "crop-raider",
feeding in cultivated fields on such items as young dry rice, cassava
leaves, rubber fruit, taro plants, coconuts, mangos, and other crops,
thus often causing significant losses to the cash incomes of local
farmers. It also takes food from graveyards, garbage cans, and garbage
pits. The species is often unafraid of humans, and is found in many
cities and villages. It has been involved in aggressive interactions
with people.
Distribution and habitat
Being "ecologically diverse", the Crab-eating Macaque is found in a
wide variety of habitats, including primary lowland rainforests,
disturbed and secondary rainforests, and riverine and coastal forests of
nipa palm and mangrove. They also easily adjust to human settlements and
are considered sacred at some Hindu temples and on some small islands,
while a pest when around farms and villages. Typically it prefers
disturbed habitats and forest periphery. The native range of this
species includes most of mainland Southeast Asia, including the Malay
Archipelago islands of Sumatra, Java, and Borneo, the islands of the
Philippines, and the Nicobar Islands in the Bay of Bengal.
Macaca fascicularis is an introduced alien species in several
locations, including Hong Kong, western New Guinea, Anggaur Island in
Palau, and Mauritius. Where they are non-native species -- particularly
on island ecosystems whose species often evolved in isolation from large
predators -- M. fascicularis is a documented threat to many native
species. This fact has led the World Conservation Union (IUCN) to list
M. fascicularis as one of the "100 Worst Alien Invasive Species".[5]
Insofar as they are present as an alien invasive on several islands,
they have been labelled a "weed" species and are yet another significant
ecological threat to those ecosystems and the species within them. It is
important to note, however, that M. fascicularis is not a biodiversity
threat in their native range, as other species therein have adapted to
their presence through evolutionary time.
Relationship with humans
Macaca fascicularis has been used extensively in medical experiments,
in particular those connected with neuroscience. It has also been
identified as a possible vector for Ebola virus and monkeypox, and is a
known carrier of B-virus (Herpesvirus simiae). Nafovanny is the largest
captive-breeding non-human primate facility in the world, and houses
30,000 macaques. The Crab-eating Macaque is one of the types of monkeys
that have been used as space test flight animals. It has been discovered
recently that Plasmodium knowlesi, which causes malaria in M.
fascicularis also can infect humans.
Conservation status
The Crab-eating Macaque has the third largest range of any primate
species, behind only humans and the Rhesus Macaque. Since the wild
harvest of the species for animal testing has been reduced by
captive-breeding programs, the total population of M. fascicularis is
not under significant threat. The IUCN Red List categorizes the species
as "Lower Risk"; and CITES lists it as Appendix II ("not necessarily
threatened with extinction, but in which trade must be controlled in
order to avoid utilization incompatible with their survival"). The
umbrosa subspecies is argued to be of important biological significance.
It has been recommended as a candidate for protection in the Nicobar
islands, where its small, native population has been seriously
fragmented (Umapathy et al., 2003). One main conservation concern is
that in areas where M. fascicularis is non-native, their populations
need to be monitored, managed, or eradicated where they have a negative
impact on native flora/fauna |
