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Why is the Red Uakari Population Declining in the Peruvian Amazon?
A study on the Peruvian uakari ecology in the larger Amazonian conservation context
Quyen Nguyen
Image Source: Arkive.org
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Abstract:
The bald uakari (Cacajao calvus) is a type of New World monkey found in flooded or
wooded forests in Amazonian Brazil and Peru whose population is being threatened by
various adverse human activities in Peru’s rainforests. This paper explores a few of what
those detrimental human activities are and examines the role of local communities in
protecting bald uakaris and preserving the larger Amazonian biodiversity.
Introduction/Background:
The Amazonian Ecosystem
Amazonia, especially the western portions at the foothills of the Andes, “stands out
as the largest and richest of the wilderness areas” (MacQuarrie 2001: 18), which means
good and bad news. The good news is that Amazonia still as the lungs of the earth with at
least “40,000 plants, of which 30,000 are endemic” (MacQuarrie 2001: 18), and it is home
to at least “1,120 birds (141 endemic), 356 mammals (210 endemic), 338 reptiles (at least
66 endemic), and 410 amphibians (326 endemic)” (MacQuarrie 2001: 19) which
concentrate particularly in the western edges of the massive forest. Unfortunately, this
incredibly biodiverse area has become one of the last remaining major tropical wilderness
areas due to human activity. By transforming Amazonian habitats from forests to cow
pastures, grasslands to croplands and swamps into cities (MacQuarrie 2001: 825), humans
are threatening the Amazon to the verge of extinction. In the tropical rainforests, it is
estimated that “a minimum of 3 to 4 animal or plant species are being lost each and every
day, which means that at least 1,000 to 1,500 species of plants & animals are being
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permanently removed from our planet each year” (MacQuarrie 2001: 326). This destructive
rate means that many of these endangered species are speedily dying out before we even
have the chance to find and study them, not to mention protect them.
Nguyen, Quyen. Amazonian biodiversity: white-lipped peccaries. 2013. Tambopata Research Center,
Peru.
Nguyen, Quyen. Amazonian biodiversity: Red & Blue Macaws. 2013. Tambopata Research Center,
Peru.
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Nguyen, Quyen. Amazonian biodiversity: Jaguar. 2013. Tambopata River, Peru.
Nguyen, Quyen. Amazonian biodiversity: Giant Otters. 2013. Tambopata River, Peru.
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Peruvian Uakari
The bald-headed uakari has a signature bright crimson bald face and “a short and
bushy tail which is less than half to only one third of the head and body length of the
animal” according to various studies done from 1981 to 2007 (Gron 2008). According to
Hershkovitz (1987) and Barnett (2005), the presence of blood vessels near the surface of
the skin results in a reddish appearance of the face and head in red-faced uakaris. (Gron
2008) The pelage of the Peruvian uakaris is reddish-orange but other uakaris’ color may
vary widely from “reddish to orange and buffy to whitish or pale yellow” (Gron 2008).
Taxonomy & Distribution
The scientific name of the red or bald-headed uakaris in Peru is Cacajao calvus
ucayalii, a reddish-orange New World monkey found only in Peru. The genus Cacajao has
quite limited distribution in Amazonian western forests, and Cacajao calvus, the bald-
headed uakari, is found in “regions of whitewater rivers, south of the Amazon, in Brazil and
Peru” (Kinzey 1997: 208-209). Besides the C. c. ucayalii, there are three other Cacajao
subspecies found in limited areas in Brazil and Colombia e.g. the C. c. calvus (white pelage)
is confined between the Rios Japura and Solimoes in Brazil. C. calvus ucayalii, the
subspecies we are examining, is only found in northeastern Peru, confined to the south by
the Sheshea River, to the north and west by the Amazon River and Ucayali River
respectively, and in the east by the Yavari River. (Gron 2008)
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IUCN (International Union for Conservation of Nature) 2008. Range of the Cacajao calvus ucayalli in northeastern Peru. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1 <http://maps.iucnredlist.org/map.html?id=3416>
Habitat & Ecology
Generally uakaris are commonly found in or close to flooded or riparian forests. As
opposed to Cacajao melanocephalus (whose face is black with plenty of dark, blackish hair)
which is found in habitats associated with "black-water rivers,” Cacajao calvus is found in
varzea forests, which is a type of Amazonian flooded forest “drained by white-water rivers
where flooding occurs up to six months of the year, depositing new sediments and
renewing the soil.” (Gron 2008) However there has been debate about whether bald
uakaris’ habitat is fixed since they can be found in several types of habitat, including both
flooded and unflooded várzea, swamp forest, white sand soil forests, floodplains and terra
firme forest near várzea (Gron 2008). This switching in terms of habitat is a result of
seasonal migration in the dry season when uakaris are said to move from previously
flooded areas to terra firme. (Kinzey 1997: 210) They often stay within flooded areas to
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enjoy periods of fruit abundance and move to “terra firme or other habitat types when
more fruit is available outside of flooded forest” (Gron 2008).
According to Leonard & Bennett (1996), Aquino (1988) and Boubli (2002), uakaris
have been found in association with “other primates including spider monkeys (Ateles sp.),
wooly monkeys (Lagothrix sp.), sakis (Chiropotes sp.& Pithecia sp.), capuchins (Cebus sp.),
and squirrel monkeys (Saimiri sp.)” (Gron 2008). Such associations might provide predator
protection (from harpy eagles, for example) and foraging benefits (Gron 2008).
Food competition occurs among uakaris and other species with a dietary overlap such as
“macaws (Ara sp.), squirrels and sympatric primates such as squirrel monkeys and
capuchins” (Gron 2008). However the level of potential competition, according to Barnett
(2005), Barnett et al. (2005) and Barnett (2008), requires additional quantitative
assessment and is predicted to be quite low (Gron 2008).
Diet
C. calvus’ diet consists predominantly of seeds of unripe fruits (67%) followed by
other parts of fruit (10%), flowers (6%), nectar, insects (5%) and unidentified foods (4%)
(Gron 2008). “Aquino & Encarnación (1999) noted C. c. ucayaliieating 53 plant species from
20 families, of which 46% were consumed for their seeds. Of these, 67% had thick heavy
husks and were consumed in the immature state” (Gron 2008). In the dry season, Peruvian
red uakaris also move to unflooded forest to feed on palm fruit (Gron 2008).
Conservation Status and Hypotheses:
According to the IUCN Red List of Threatened Species (2008), the bald uakaris,
Cacajao Calvus, are categorized as Vulnerable. Here is a history of the IUCN’s assessment of
the C. calvus over the years (Veiga et al. 2008):
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2003 – Near Threatened (IUCN 2003)
2003 – Near Threatened
2000 – Vulnerable
1996 – Vulnerable (Baillie and Groombridge 1996)
1996 – Vulnerable
1994 – Endangered (Groombridge 1994)
1990 – Vulnerable (IUCN 1990)
1988 – Vulnerable (IUCN Conservation Monitoring Centre 1988)
1986 – Vulnerable (IUCN Conservation Monitoring Centre 1986)
1982 – Vulnerable (Thornback and Jenkins 1982)
Compared to the assessment in 1994 which put bald uakaris into the pool of endangered
animals (only two steps away from completely extinction), the 2008 status of ‘vulnerable’
is somewhat more hopeful, indicating that conservation work had been done to rectify the
dangerous drop in uakaris’ population in 1994. However, if we look at the 2003
assessment, uakaris’ have shifted closer to the extinction side of the spectrum by moving
from Near Threatened in 2003 to Vulnerable in 2008. The IUCN’s justification for this
change is that “there is reason to believe the species has declined by at least 30% over the
past 30 years (three generations) due primarily to hunting and habitat loss” (Veiga et al.
2008).
This paper explores those reasons that contribute to the uakari population decline
for the past three decades with two main hypotheses:
1. Hunters preying on uakaris for bush meat are causing their population to
decline.
2. Loggers who destroy uakaris’ arboreal habitat are depriving them of their
home and food source.
Hunting and logging are two main causes of Amazonia’s biodiversity and my hypotheses
propose that they are the dominant actors causing uakaris’ population to decrease over the
years. Biological factors such as the uakaris’ low reproductive rate (Barton 2006: 4) or
their high rate of malaria infection (Gron 2008) might contribute to their slow recovery but
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the external, human-induced effects are the more detrimental forces against uakaris’
population growth. After all, it is humans who have caused current extinction rates to
skyrocket from 100 to 1000 times the normal extinction rate in the past, making the past
two hundred years an “extinction spasm” (MacQuarrie 326) as catastrophic as the mass-
extinction of all dinosaurs 65 million years ago. While the Mesozoic period came to a close
due to an impact of a meteor collision, homo sapiens have managed to speed up our own
destructive process entirely through man-made exploitative activities (MacQuarrie 326).
Findings:
HUNTING
Uakaris are susceptible to hunting due to its primary range close to rivers (varzea
forests). Aquino (1988) has suggested that uakari populations “close to the Ucayali and
Amazon Rivers have been greatly reduced and in some areas exterminated, caused by
hunting and habitat disturbance” (Veiga et al. 2008). Due to their riparian habitat, uakaris
are prone to hunters, either preferentially hunted or taken when other primates are
unavailable (Barnett and Brandon-Jones 1997).
Hunted for Meat
Sightings in 2003 of C. c. ucayalii on the Quebradas Tangarana and Tahuaillo in Peru
show that the local C. c. ucayalii populations were frequently hunted. “On the Quebrada
Blanco, we met a local hunter carrying a dead female that he had shot an hour’s walk from
our camp,” Ward and Chism (2003) report. “Later, two tourists informed us that they met a
hunter carrying two dead red uakaris at the same campsite. […] A Jivaro Indian at Neuvo
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Jerusalem [told] us he had shot three (a male and two females, one with an infant) while
hunting the previous week.” (Ward and Chism 2013: 21)
In Amazonia, according to Peres (1990), subsistence hunting has always played an
important role in indigenous peoples’ lifestyle (Ward and Chism 2003: 21). The locals
strongly prefer larger cebids to smaller New World monkeys for their higher quantity and
quality of meat, making them cost-effective to hunt (Ward and Chism 2003: 21). During the
later half of the twentieth century, as the Peruvian population increased as urbanization
took place, dried or smoked monkey meat became a common food source for the protein
hungry frontier village and town dwellers. (Soini 1972: 26) Attractive to local hunters as
they are, large cebids’ populations are therefore prone to becoming locally extirpated.
Their slow reproductive rates also lowers recovery chances. Populations of the larger
primates in the Río Tapiche basin and the Quebrada Blanco-Río Yavari corridor are
reported to have declined dramatically (Ward and Chism 2003: 21).
As soon as the once stable stocks of larger monkeys have been depleted, the flesh of
smaller monkeys will automatically enter the market. (Soini 1972: 26) Ward and Chism
also came to a similar prediction that red uakaris will experience the same fate as larger
primates due to “being ‘next in line’” in terms of body mass after the woolly (Lagothrix
sp.), spider (Ateles sp.), and howler (Alouatta sp.) monkeys. At least around the
Reserva Comunal Tamshiyacu-area in northearstern Peru, sightings of only one troop of
woolly monkeys and no howler or spider monkeys have convinced researchers that the C.
c. ucayalii are the next potential victims of local hunters (Ward and Chism 2003: 21).
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Non-human primate species of Manu; for more information see Pacheco et al. (1993). Neotropical Primates. 13(2): 31–36. 2005. doi: http://dx.doi.org/10.1896/1413-4705.13.2.31
Harvested for other purposes
Since the time of pre-Columbian Indians, Amazonian monkeys were already much
exploited by man for not just food but also household pets (Soini 1972: 26). Red uakaris in
Peru to this day still suffer from this irrational human demand for monkey pets. At Jaldar
Village on the Rio Yarapa, an area in Peru where high density of uakaris are found, an
employee at Tahuayo Lodge and a villager each possessed a female infant as pets, as
observed by a group of researchers (Ward and Chism 2013: 21). “Four male C. C. ucayalii,
two subadults and two juveniles housed at a lodge on the Rio Yarapa, were all obtained as
infants when their mothers were killed by Jivaro Indian hunters on the Rio Tahuayo”
(Ward and Chism 2013: 21).
LOGGING
Deforestation
The reduced region of uakari habitat can be seen in Conservation International’s
map (below) displaying the original range of Peruvian uakaris in and how it had shrunken
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by 1986. According to Bowler (2007), logging concessions designated in 2004 in
northeastern Peru cover around one-third of the geographic range of Cacajao c. ucayalii,
furthering the extension of human activity and reducing uakaris’ intact habitat even more
dramatically. While the selective removal of low-density, high-value timber species may
not have a great impact on populations of Cacajao c. ucayalii, Bowler proposes that the
logging operations increase human populations and bushmeat hunting in remote parts of
the range (Veiga et al. 2008).
(Bowler et al. 2009: 36)
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Bowler, Mark. Lago Preto Map. 2008. <http://www.mbowler.mistral.co.uk/lagopreto/images/Lago%20Preto%20location%20map%20(from%20Bowler%20et%20al.%202008).jpg>
Mongabay News. Deforestation in Peru. 2013. <http://news.mongabay.com/2013/0613-peru-deforestation-tracking-system.html>
Looking at Peru’s deforestation rate in the graph above, we see that since 2009 it
has reduced in terms of intensity, yet the deforestation rate in Loreto (northeastern Peru
where uakaris are found) has stayed consistently high in proportion to other areas. No
Deforesta on&Non-TimberForestExtrac on
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tests have been performed to show the direct causal effects of deforestation to uakari
population decline but it is undeniable that the process of deforestation enables human
activity, especially hunting, to occur more easily.
Aguaje extraction
As mentioned above, uakaris’ diet consists of mostly seeds from immature fruits,
especially from aguaje (Mauritia flexuosa) palm fruits. Barton (2006) has done a study to
show that aguaje seeds account for 22.4% of uakaris’ entire diet list (see below.)
However, as aguaje fruits become more in demand, unsustainable extraction practices
threaten to deplete Peru’s aguaje resource and deprive the animals that feed on aguaje of
their food source. According to the National Geographic, aguaje fruits generate $4.6 million
every year in the markets of Iquitos, “more than any other indigenous fruit from the
Peruvian Amazon” (Rutger 2008). Not only consumed as a local fruit, aguaje fruits are also
used in “ice cream, popsicles and cold drinks, and is the richest natural source of vitamin A
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yet known (Pacheco Santos, 2005)” (Manzi 2009: 510). Recent advertisements of aguaje as
the new “superfruit” for women as it contains Phytoestrogens, a “natural estrogen,” are
being widely distributed online through commercial websites such as curvyfruit.com are
also boosting the demand for aguaje even though the information advertised is by no
means endorsed by the FDA or any legitimate organizations.
Nguyen, Quyen. Aguaje palm trees in swamp forests. 2013. Tambopata Research Center, Peru.
“Recent estimates suggest that residents of Iquitos, the largest city in the region,
consume approximately 148.8 metric tons of aguaje fruit per month, the vast majority of
which is harvested by felling and killing adult female trees” (Gilmore et al. 2013). Although
aguaje has brought in in a significant amount of income for rural families (see graph below),
how it is traditionally extracted threatens to considerably reduce aguaje availability for future
extraction. Since the aguaje palms are naturally tall – it could get over 30m high (Manzi 2009:
510) – locals tend to “fell the female palm to secure the fruit” (Manzi 2009: 510) since it is
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difficult and dangerous to climb the trees. This practice makes aguaje extraction in Peru doubly
unsustainable because people are not only cutting down an entire tree to extract short-term
fruits but also killing off a disproportionate amount of female trees which might result in
genetic erosion among the aguaje trees. To resolve this issue, in 2001 a palm-climbing device
was developed by two brothers from the community of Parinari in order to introduce an
alternative method of extracting aguaje fruits (Manzi 2009: 512). This proved to be a great
device for aguaje extraction and easy to use. The price of the device, however was $75, which
was too expensive for an average household. Communities end up having to share these
devices and reserving them for the most advanced climbers (Manzi 2009: 513). The use of the
climbing device did lead to the protection of 40ha of aguaje in Roca Fuerte (Manzi 2009: 513)
but had the devices been designed to be cheaper, even more hectares of aguaje might have
been saved.
Mean household total income by source, January–December 2002, Roca Fuerte, Peru. Notes: mean household total income measures household total annual production (i.e., consumption and market income). ‘Other Extraction’ measures income from all other aquatic and terrestrial extractive activities besides aguaje palm fruit extraction (i.e., paiche fishing, aquarium fish collection, timber, firewood, and heart of palm extraction, chonta, etc.). Gini coefficient measures income distribution across households. A low Gini coefficient indicates more equal income distribution, whereas a high Gini coefficient indicates more unequal distribution. (Manzi 2009: 510)
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Climbing of aguaje palm and harvesting of fruit, Roca Fuerte, 2003. Note: aguaje harvesting comprises the following steps: (a) using the stirrup to ascend; (b) sliding the upper strap upward and tightly clutching the strap around the palm; (c) sliding the lower strap upward while sitting in the harness and tightly clutching the strap around the palm; (d) locating one foot in the stirrup and repeating steps (a)–(d) until reaching the crown; (e) cutting down the racemes with the machete or saw; (f) stripping the fruit from each raceme (desgranar) and filling the sacks; (g) transporting the sacks. (Manzi 2009: 512)
To return to the connection between Peruvian uakaris and aguaje palms, we have
seen uakaris’ clear dependency on aguaje as a food source and how the unsustainable
extraction of aguaje will lead to the depletion of aguaje trees and hence, a reduction in
uakaris’ favorite seeds. In 2006 Bowler took notice of this striking connection between
uakaris and aguaje trees and predicted that “in certain parts of the red uakaris range the
removal of this non-timber resource will have a more serious impact on uakari populations
than logging. A paper discussing these findings is currently in preparation” (Bowler 2006:
1). The promised paper has not been published and we still do not have a concrete
argument that excessive aguaje extraction is responsible for the uakaris’ population
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decline. However, considering that the aguaje palm is a keystone species that not only
offers food for various animals but also provides “food, fiber, oil, medicinals, materials for
construction and fishing equipment” for humans (Manzi 2009: 510), sustainable
approaches to aguaje extraction should be developed and implemented as soon as possible.
Conclusion & Recommendation:
In conclusion, we have established that uakaris are susceptible to hunting for its
meat and also as pets. They are the next-in-line target for bushmeat hunters to prey upon
once the larger primates in the area have been depleted. In order to stop the bushmeat
trade from thriving, more research needs to done to find out what other affordable protein-
rich food can be cultivated to replace bushmeat for local communities. Also the lack of
knowledge about Amazonian ecosystems also perpetuates the locals’ indiscriminate
hunting without considering their action’s long-term consequences. This is where non-
profits and the government need to step in to increase the locals’ awareness of how
important uakaris (or any other species) is to an ecosystem like the Amazon, which
Vandermeer and Perfecto have compared to a highly connected web of multiple strong
connections (Vandermeer and Perfecto 2005: 18). A simple example of the interconnected
nature of an ecosystem is how the uakaris’ search for aguaje seeds leads to a cascade of
aguaje fruits down to the forest floor, which then become food for other animals like tapirs,
76% of whose diet comes from aguaje fruits (Torres 2013: 8).
In terms of logging and non-timber extraction, we predict that deforestation may
not directly harm uakaris’ arboreal habitat but it certainly opens doors to hunters and
other human activities such as mining or highway construction to occur closer to the
uakaris’ range. Similarly, the extraction of aguaje fruits has not been shown to explicitly
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hurt uakaris’ population but since we know uakaris rely majorly on aguaje fruits for their
seeds, it is recommended that aguaje trees should be extracted sustainably so as to keep its
number growing. Besides making palm-climbing devices more affordable to local climbers,
integrating aguaje cultivation into local communities’ agroforestry agenda has also yielded
positive results, an example of which is the “dwarf” aguaje recently cultivated in Peru: Due
to the trunk’s shorter height, this type of aguaje fruit can be extracted without felling or
even climbing the trees (Torres 2013: 49). Sustainable agroforestry such as the aguaje
cultivation in northeastern Peru not only provides low-income families with a more steady
income but also contributes to the positive reconciliation of the tension between
conserving Amazonian biodiversity (uakari population, in this case) and acknowledging
local communities’ dire economic needs.
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Works Cited Barnett, Adrian, and Douglas Brandon-Jones. "The Ecology, Biogeography and Conservation of the Uakaris, Cacajao (Pitheciinae)." Folia Primatol 68 (1997): 223-235. Print. Barton, Christopher. The Behavior, Ecology and Population Viability of the Red Uakari Monkey, Cacajao calvus ucayalii, in the Lago Preto Conservation Concession, Peru (Paper). Peru: Wildlife Conservation Society (WCS) Peru, 2006. Print. Bowler, Mark. "The Red Uakari Monkey Project – End of Year Report." The Rufford Foundation. N.p., 22 May 2006. Web. 4 Oct. 2013. <www.rufford.org/files/2-120.01.05%20Detailed%20Final%20Report.doc>. Bowler, Mark, Javier Murrieta, Maribel Recharte, Pablo Puertas, and Richard Bodmer. "Peruvian Red Uakari Monkeys in he Pacaya-Samiria National Reserve."Bioone 16 (2009): 34-37. Print. Gilmore et al., Michael. "The socio-cultural importance of Mauritia flexuosa palm swamps (aguajales) and implications for multi-use management in two Maijuna communities of the Peruvian Amazon." J Ethnobiol Ethnomed. 9 (2012): 1. Print. Gron, Kurt. "Primate Factsheets: Uakari (Cacajao) Conservation." National Primate Research Center. University of WIsconsin-Madison, 21 July 2008. Web. 1 Oct. 2013. <pin.primate.wisc.edu/factsheets/entry/uakari/cons>. Kinzey, Warren G.. New World primates: ecology, evolution, and behavior. New York: Aldine de Gruyter, 1997. Print. MacQuarrie, Kim, Andre Ba rtschi, and ussell A. Mittermeier. Where the Andes meet the Amazon: Peru and Bolivia's Bahuaja-Sonene and Madidi National Parks. Spain: Jordi Blassi, 2001. Print. Manzi, Maya. "Managing Amazonian palms for community use: A case of aguaje palm in Peru." Forest Ecology & Management 257 (2009): 510-517. Print. Rutger, Hayley. "After Acai, What Is Amazon's Next "Cinderella Fruit"?." Daily Nature and Science News and Headlines | National Geographic News . N.p., 14 Oct. 2008. Web. 14 Oct. 2013. <http://news.nationalgeographic.com/news/2008/10/081014-amazon-fruit-missions.html>. Soini, P. (1972), The capture and commerce of live monkeys in the Amazonian region of Peru. International Zoo Yearbook, 12: 26–36. doi: 10.1111/j.1748-1090.1972.tb02260.x Torres, D Castillo . "Aguaje - The Amazing Palm Tree of the Amazon." Instituto de Investigaciones de la Amazonía Peruana. N.p., n.d. Web. 9 Sept. 2013. <www.iiap.org.pe/Upload/Publicacion/L028.pdf>.
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Vandermeer, John H., and Ivette Perfecto. Breakfast of biodiversity: the political ecology of rain forest destruction. 2nd ed. Oakland, Calif.: Food First Books ;, 2005. Print. Veiga, L.M., Bowler, M., Silva Jr., J.S., Queiroz, H.L., Boubli, J.-P. & Rylands, A.B. 2008.Cacajao calvus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>. Downloaded on 14 October 2013. Ward, Nancy, and Janice Chism. "A Report on a New Geographic Location of Red Uakaris (C. c. ucayalii) on the Quebrada Tahuaillo in Northeastern Peru." NEOTROPICAL PRIMATES 11 (2003): 19-22. Print.
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