Abstract
In Colombia, there are approximately 27–31 primate species, including at least five endemic ones and a high proportion of threatened species. Differences in these primates' distribution, abundance, ecology, and charisma, among many other things, have led to large variation in the amount and nature of investigations performed on the different species. Basic information on each native primate species is necessary to build adequate conservation plans; therefore, knowledge of the quantity and type of information available on each species can be helpful to identify possible research gaps. Based on publications from 1900 to 2008 on 25 primate species present in Colombia, we evaluated primate research in this country in terms of quantity, type, and topics of investigation. Additionally, we comparatively assessed the role of Colombian primatology within all scientific production on primate species present in this country. Our analyses indicate that in Colombia, primate research has developed mainly in the field-work area, with studies focused primarily on ecology and behavior. Investigations of topics such as karyology, anatomy, and physiology are very limited, and molecular biology is understudied compared to research on this subject in other countries. Captive studies are also comparatively scarce. Our analyses also suggest that those species distributed in areas where research stations are located have been the focus of a greater proportion of investigations. A few study sites (PNN La Macarena, Rio Peneya Station, PNN Tinigua, and Caparu Biological Station) stand out as primate research “hot-spots” within Colombia; however, field work in these stations is frequently jeopardized by the constant threat imposed by revolutionary armed forces in the rural and forested parts of Colombia.
Introduction
Colombia is a mega-diverse country, ranking within the top 12 countries in terms of species diversity [1, 2]. Colombia has been reported to be the country with the highest number of bird and amphibian species, the second of plants, third of reptiles and fifth of mammals [2]. For many groups of organisms, this diversity has been associated with ecosystem diversity and topographic variability [3], as well as the confluence of several bio-geographical units, allowing the presence of Central American, Amazonian, and Andean biota. Regarding neotropical primates, Colombian forests are inhabited by a large number of species as well [4]. In the third edition of
Factors such as species distribution, population size, species ecology and behavior, researcher accessibility to locations within species distribution, and availability of research centers, among many others, can influence in different ways the numbers, types, and topics of studies performed on the different primate species. For instance, it is expected that abundant and more widely distributed species will tend to be more studied due to practical reasons. Species attractiveness and charisma can also influence a researcher's interests, while differences in species' ecology and behavior can encourage research on certain topics over others. On the other hand, the type of studies carried out is expected to vary according to the accessibility to field stations, laboratories, and/or captive centers; and it may be also influenced by the continuity of established lines of investigation that focus on certain types and topics of study, and on particular locations or research centers (e.g., major projects within specific study sites). In Colombia, in particular, there is an additional and determinant factor that greatly alters research activity: the presence of revolutionary armed forces and intense drug-trafficking activities in several rural areas, which impose several limitations on field studies. All these factors relating to the amount and kind of information available on the different primate species present leads to fragmented knowledge, and in many cases it also leads to misconceptions of the conservation status of species and populations. Critically endangered or endemic species such as
In this paper we evaluate primate research in Colombia in terms of number, type, and topics of study, based on publications from 1900 to 2008 on 25 native primate species. Our principal aim was to assess generally the patterns and tendencies that have driven the development of primate research in Colombia, by examining how many and what type of studies have been undertaken on each species; and by establishing which have been the central topics of these investigations. Finally, we evaluate the relative contribution of Colombian research to the information available on the different primate species found in Colombia, compared to the contribution of foreign publications.
Methods
Database
We generated a bibliographic database composed of a sample of publications (n=3149) from 1900 to 2008, on 25 primate species occurring in Colombia. The compilation of publications was composed of articles, books and book chapters (official publications), and theses, reports, and abstracts (“gray” literature) obtained from different sources including: (1) international online databases such as Web of Science and Google Scholar, (2) open journal web sites, (3) personal archives, and (4) specialized databases (i.e., Primate Lit, University of Wisconsin: http://primatelit.library.wisc.edu/). Complete bibliographic information is available from the authors upon request. We also gathered information on the dates and locations (political and geographical regions) where field studies were carried out in Colombia.
Publications reporting research on more than one species were assigned to all the Colombian native species included in the document.
Classification
Each publication was assigned to one of four types of research: review, laboratory, captivity, and field studies. Review studies were defined as research based mainly on previously published information; laboratory studies were defined as any type of research with an approach carried out in laboratory settings or requiring special equipment during data gathering in captivity; captive studies were defined as research carried out in zoos, research centers, or confinement facilities; and field studies were defined as any type of research carried out at field locations within the natural distribution area of the studied species. We encountered a few cases where the primary type of research was not evident (e.g., a laboratory phase and a field phase of similar proportions within a single investigation), therefore these publications were classified as mixed-type study.
Each publication was assigned to one of seven possible research topics: (1) anatomy and physiology, (2) behavior and social organization, (3) conservation and monkey-human interactions, (4) ecology and natural history, (5) evolution and systematic, (6) geographic distribution, and (7) parasitology and veterinary (including studies when primates are study subjects in medical tests). Publications addressing different topics were assigned to each of the corresponding topics. Additionally, each publication was assigned a country of origin according to (1) the country in which the field work was carried out in the case of field studies, or (2) the author(s) affiliations at the time of the study, in the case if laboratory, captivity, or review papers.
Analyses
Publications were organized based on the four different types of research (review, captivity, laboratory, and field studies), and in order to compare the relative proportion of each of the different types of publications, we used association G tests. Since a single publication could be assigned to several species and more than one research topic, these were treated as several records according to the different number of included species and assigned topics (n=4396). A record was therefore defined as a single entry for a particular publication. A single publication could thus generate many entries depending on the number of species and topics included. For example, a publication titled “Activity patterns and diet of woolly and spider monkeys” would be assigned to four records (two topics: behavior and ecology, for each species).
In order to compare the number of field study records between Colombia and other countries we generated an expected number of studies for each primate species. This number was calculated assuming that the proportion of studies in the country should be proportional to the percentage of the species' geographic range corresponding to Colombian territory. Maps for the distribution of the 25 primate species were obtained online form the IUCN Red List web page [7]. For each species, the percentage of the species' total area of distribution within Colombian territory was calculated as a proportion of total distribution area using the image processing software ImageJ (2008) (
Results
General description
Overall, a total of 4,396 records were registered out of 3,157 primate publications. For Colombia 833 records were obtained from 409 publications, compared to 3,563 records out of 2,748 publications for other countries. The most common type of research in Colombia is field studies, which represent almost 80% of the total research carried out in this country. Even though we found a higher number of field studies in other countries, the percentage represented by this type of research in Colombia almost doubles its percentage for other countries. In contrast, very few captivity and laboratory studies were found for Colombia compared to other countries, with more than four and three times fewer publications in these areas respectively (Fig. 1).

Comparison between the percentages of review, laboratory, captivity, field and mixed-type of publications on 25 primate species found (A) in Colombia (N=409) and (B) other countries (N=2,748).
A significant association was found between Colombia and other countries in terms of types of publications (official publications = articles, book chapters and books; and “gray” literature, which includes abstracts, theses, and reports) (n=3157, G=35.2, 1df, p<0.0001). From the 409 registered publications for Colombia, 169 corresponded to “gray” literature and 240 to official publications, compared to 733 and 2,016 respectively for other countries out of a total of 2,749. This means that primate research in Colombia has less tendency to be formally published (1.4 publications per registered “gray” literature research project) compared to foreign research (2.8 publications per registered “gray” literature research project) (Table 1). When considering officially published records only for Colombia, we found that
Types of literature registered for Colombia and other countries. Comparison between the number of studies and records in the form of articles, book chapters, books, theses, abstracts and reports on 25 primate species found in Colombia.

Comparison of the published study topics for different primate species in Colombia.
Our evaluation on the topics addressed by primate studies in Colombia indicates that ecology and natural history (200 records) has been the preferred topic, while parasitology and veterinary (8) appears as the least explored topic in national research. In contrast, foreign research shows a tendency towards behavioral and social organization-oriented studies (870), whereas geographical distribution and conservation and monkey-human interaction studies (113 and 116 records, respectively) have been addressed less often (
Review studies
Altogether, reviews added up to a total of 173 publications and 766 records. Of the 729 officially published records, 247 corresponded to publications from authors affiliated to Colombian institutions, while 482 were from authors affiliated to institutions elsewhere. The number of records out of foreign publications corresponded mainly to American (273), followed by Brazilian (71), and British (51) affiliations. Reviews have been focused primarily on primate ecology and natural history (231), followed by conservation and monkey-human interactions (153) as the second preferred topic of study. Parasitology and veterinary was the least reviewed topic with less than 10 registered records. Even though review studies usually include several species,
Laboratory and captive studies
The laboratory and captive research sample consisted of a total of 1,687 records obtained from 1,471 publications. Of these, 1,304 were from official publications and the majority was found to be focused on behavior and social organization (426 records), followed by anatomy and physiology (325), evolution and systematics (245), and parasitology and veterinary (192).
Field studies
Overall, 323 publications were listed for field studies in Colombia, resulting in a total of 489 records. For other countries we found total of 1,466 records representing 1,194 publications. Official publications for Colombia generated up to 310 records, while records from official foreign publications summed up to 1,004.
Our analysis of official publications shows that ecology and natural history was the most examined topic among field studies both in Colombia and other countries (200 and 522 records, respectively), with behavior and social organization as the second most studied topic (122 and 382. respectively). Our results also reveal
We found a high number of records corresponding to field studies in Colombia (310), compared to the expected number (247). Taking into account total distribution ranges and the proportion of total area within Colombian territory for each of the 25 primate species considered in the analysis, it is clear that

Comparison between the number of published-records for primate field research carried out in Colombia and the expected number, according to proportion of total geographic range in Colombian territory.
In relation to the regions in Colombia where the highest number of studies has been carried out, we found that Meta department represents more than half of all the field studies performed in the country. Meta, Vaupés, and Caquetá appear as the next preferred locations for primate research studies (Fig. 4). However, when looking into the timeline of field study research in Colombia, our results show a pulsing tendency with several research peaks across the years. These peaks appear to be associated with periods of major field projects that are in turn related to particular research stations and generally include several primate species (Fig. 5). However, our results also show a recent decrease in the number of field studies carried out in Colombia compared to other countries (Fig. 5). This decline is clearly associated with the civil conflict affecting the regions where key stations are located, some of which have been closed (e.g., CIEM station in Tinigua National Park in Meta, closed in 2002; Estación Investigaciones Primatológicas del INDERENA in Sucre, closed in the early 1990s).

Frequency of study records from field stud carried out in different regions of Colombia (state departments) between 1900 and 2008.

Number of field study records generated through time from primate studies in Colombia. It is important to note that the year represents the time when field work was done and not the year of publication. The peaks in field work can be associated with particular projects: (1) Klein & Klein in PNN La Macarena, Meta, (2) Izawa & Nishimura's studies in Rio Peneya, Caquetá, (3) First studies at CIEM, PNN Tinigua, Meta; and some studies by Defler in Caparu, Vaupés, (4) Stevenson, Quiñones & Ahumada studies with four species in Tinigua NP. 5. Stevenson's final year for his PhD thesis in Tinigua NP, Meta). The line showing information from other countries was based on publication years.
Discussion
Our evaluation of primate research in Colombia indicates that field studies constitute the main type of research in the country, while laboratory and captivity studies are quite uncommon. However, even though numerous publications have been produced through this type of research, there appears to be a bias for particular species, disregarding many others. One potential explanation for these differences may relate to researchers' and students' preferences. In general, in Colombia there is the possibility of carrying out observations in natural conditions on a wide variety of ecosystems; therefore, this type of research may be chosen over captive or laboratory studies since it allows the possibility to study the species in their natural habitat. Publications based on field studies may also be the most important sources of information when looking for the most relevant aspects of a species' biology for the design of conservation plans.
Species biases among field studies are also generated by the availability of suitable study sites. For instance, the three most studied species in Colombia, woolly monkeys, brown capuchins, and red howler monkeys, were all subject to investigations at the CIEM (Centro de Investigaciones Ecológicas La Macarena) and Caparú research stations, the most productive sites in terms of ecological and behavioral publications. In contrast, the paucity of studies on mantled howler monkeys (
Our analyses make evident the lack of information from captive and laboratory studies in Colombian primate research. We believe that, in the short term, primatologists in Colombia should regard some of the available zoos in the country as possible sites for captive studies, but in the long term construction of more specialized captive research centers should be considered to promote knowledge of primates. More importantly, this would also contribute to relieving the urgent need to have holding stations for confiscated wildlife in the country. On the other hand, laboratory studies (focused mainly on phylogenetic relationships and systematics) are now more common in Colombia than they were several years ago [11]. However, from our analyses it is evident that, in Latin America, Brazil is leading the research in this area. Laboratory studies, particularly the ones resulting from the recent implementation and diffusion of molecular techniques, are crucial in the determination of a population's taxonomic status, and are also relevant for conservation plans. Some populations may need extreme protection if it is confirmed that they belong to independent evolutionary units, such as of
Regarding the potential to produce official scientific literature, the country exhibits a low proportion of successful official publications originated from “gray” literature [11]. This also seems to be the case in other Latin-American countries, such as Mexico (Serio-Silva, pers. comm.). Attempts to achieve publications of high-quality research in journals and books must therefore be encouraged among Colombian researchers and students in order to make a real contribution to primate knowledge. The understudied
Our review identifies a set of species that remains greatly understudied both in Colombia and other countries, including
Implications for conservation
It is clear that the conservation of Colombian primates depends in part on scientific knowledge that is the basis for management plans. Despite the efforts of many primatologists, we are far from generating accurate models that can predict the viability of populations inhabiting complex tropical forests, even for the most studied species. Given the variable ecological and behavioral knowledge available for primates in the country, we recommend studies of species with the least available information (see above) and for species with the highest risk of extinction. According to the international IUCN conservation rankings (

Pictures of four highly endangered primate species in Colombia. Pictures were taken by (A) Pablo Tovar, (B) Andres Link, (C) Sergio Vargas, (E) Juan Diego Garay-Hoyos, (D and F) Diego Alejandro Zárate.
Concomitantly, there are specific projects focusing on the conservation of some of the most vulnerable species. Proyecto Titi, is a long term project led by A. Savage focusing on the conservation of
Based on our experience, we believe that to ensure the conservation of Colombian primates it is not only necessary to acquire integral scientific knowledge on each species, but also essential to protect the forests and ecosystems inhabited by the monkeys. In Colombia, about 9.65% of the terrestrial area corresponds to parks within the national system of protected areas [2], and this area has been increasing through the years, but primate protection is not guaranteed in protected areas. For example, annual deforestation rates of 1.5–4.1% have been reported in the National Parks including the critically endangered cotton-top tamarin in Northern Colombia [18]. Increasing deforestation rates have been reported for Tinigua National Park [19], where the highest population densities of the endangered Colombian woolly monkeys have been reported [6]. In 7 out of 51 national protected areas, more than half the territory has been transformed by man. In 29 of them, the percentage disrupted area lays between 1% and 50%. The remaining protected areas show natural habitats in fairly good conditions [2]. Therefore, since habitat loss is the single most critical factor affecting diversity throughout the country, additional efforts are needed to prevent forest destruction within and outside national parks.
Apart from forest destruction, endangered populations suffer from hunting, especially large-bodied monkeys such as
Footnotes
Aknowledgments
Part of this review was based on a previous search and we thank all the students from the Laboratorio de Ecología de Bosques Tropicales y Primatología, who kindly helped: Ana María Aldana, Juliana Agudelo, Marta Beltrán, Marcos González, Adriana Guzmán, Ana Cristina Palma, Johana Torres, and Ivonne Vargas. We dedicate this study to all the researchers who have contributed to the advance of Colombian Primatology.
Appendix 1. Approximated values for total geographic distribution area,distribution area in Colombia,and percentage of total distribution belonging to Colombian territory,for 25 primate species. Maps were taken from http://www.iucnredlist.org/ (IUCN 2008) and analyzed with ImageJ 1.41 (2008).
| SPECIES | TOTAL AREA (km2) | AREA IN COLOMBIA (km2) | PERCENTAGE OF AREA IN COLOMBIA |
|---|---|---|---|
|
|
346,260 | 49,410 | 14.3% |
|
|
3′672,610 | 596,170 | 16.2% |
|
|
Endemic | 72,050 | 100% |
|
|
336,750 | 246,290 | 73.1% |
|
|
612,170 | 218,720 | 35.7% |
|
|
2′546,710 | 217,430 | 8.5% |
|
|
696,040 | 60,490 | 8.7% |
|
|
102,740 | 75,320 | 73.3% |
|
|
303,170 | 106,530 | 35.1% |
|
|
154,620 | 17,090 | 11.1% |
|
|
995,390 | 254,430 | 25.6% |
|
|
320,660 | 50,960 | 15.9% |
|
|
1′029,100 | 97,200 | 9.4% |
|
|
2′247,760 | 114,240 | 5.1% |
|
|
5′895,900 | 376,080 | 6.4% |
|
|
296,960 | 94,240 | 31.7% |
|
|
1′743,140 | 369,200 | 21.2% |
|
|
428,930 | 71,840 | 16.7% |
|
|
1′080,220 | 79,480 | 7.4% |
|
|
46,260 | 26,360 | 57.0% |
|
|
233,320 | 112,470 | 48.2% |
|
|
Endemic | 35,550 | 100% |
|
|
132,740 | 65,250 | 49.2% |
|
|
Endemic | 24,590 | 100% |
|
|
2′694,930 | 328,990 | 12.2% |
Appendix 2. Published study-records in different topics for the primate species found in Colombia. Numbers in parenthesis represent the number of records in other countries.
| Species | Anatomy and physiology | Behavior and social organization | Conservation and monkey-human interactions | Ecology and natural history | Evolution and systematics | Geographic distribution | Parasitology and veterinary |
|---|---|---|---|---|---|---|---|
|
|
1 (26) | 1 (89) | 5 (18) | 4 (124) | 2 (9) | 3 (10) | 0 (7) |
|
|
1 (14) | 17 (37) | 5 (12) | 37 (76) | 5 (21) | 3 (12) | 0 (4) |
|
|
1 (0) | 1 (0) | 4 (1) | 2 (1) | 3 (8) | 1 (0) | 0 (0) |
|
|
1 (5) | 1 (12) | 5 (1) | 4 (5) | 3 (11) | 2 (1) | 7 (24) |
|
|
1 (2) | 3 (4) | 4 (2) | 3 (15) | 7 (8) | 2 (1) | 0 (18) |
|
|
1 (4) | 8 (14) | 6 (4) | 23 (45) | 2 (10) | 3 (5) | 0 (2) |
|
|
1 (34) | 1 (59) | 4 (9) | 2 (52) | 2 (17) | 2 (9) | 0 (3) |
|
|
1 (1) | 1 (0) | 6 (2) | 3 (1) | 1 (6) | 2 (3) | 0 (1) |
|
|
1 (2) | 2 (2) | 4 (0) | 6 (11) | 1 (9) | 2 (7) | 0 (0) |
|
|
1 (3) | 11 (20) | 5 (1) | 6 (14) | 2 (8) | 3 (3) | 0 (0) |
|
|
1 (3) | 2 (5) | 4 (1) | 6 (21) | 2 (9) | 3 (5) | 0 (1) |
|
|
1 (41) | 1 (32) | 3 (4) | 2 (33) | 1 (27) | 3 (4) | 0 (7) |
|
|
1 (15) | 4 (32) | 4 (3) | 3 (32) | 1 (21) | 2 (5) | 0 (2) |
|
|
1 (5) | 5 (8) | 5 (4) | 4 (16) | 4 (11) | 3 (5) | 1 (0) |
|
|
1 (24) | 26 (161) | 8 (13) | 14 (71) | 3 (10) | 3 (12) | 0 (8) |
|
|
1 (6) | 1 (83) | 4 (3) | 2 (51) | 1 (8) | 3 (4) | 0 (1) |
|
|
1 (16) | 20 (18) | 7 (4) | 41 (36) | 6 (22) | 3 (4) | 0 (16) |
|
|
1 (2) | 2 (1) | 5 (1) | 3 (15) | 1 (3) | 2 (2) | 0 (0) |
|
|
1 (60) | 2 (82) | 5 (3) | 2 (74) | 1 (18) | 2 (6) | 0 (9) |
|
|
1 (6) | 1 (10) | 4 (4) | 2 (14) | 1 (7) | 2 (1) | 0 (3) |
|
|
1 (2) | 1 (3) | 4 (0) | 5 (5) | 1 (3) | 2 (1) | 0 (0) |
|
|
1 (1) | 1 (0) | 6 (2) | 4 (1) | 1 (3) | 3 (1) | 0 (0) |
|
|
1 (5) | 2 (2) | 5 (2) | 3 (12) | 1 (3) | 2 (5) | 0 (1) |
|
|
2 (69) | 2 (131) | 14 (14) | 8 (27) | 1 (31) | 2 (1) | 0 (63) |
|
|
1 (27) | 6 (65) | 5 (8) | 11 (35) | 5 (8) | 2 (6) | 0 (14) |
|
|
|
|
|
|
|
|
|
|
|
6.5 | 12.3 | 53.0 | 20.3 | 16.6 | 34.7 | 4.1 |
Appendix 3. Conservation status history for 31 primate species occurring in Colombia,according to data taken from IUCN Red List of Endangered Species (IUCN 2008). Taxonomic notes for this classification are available in each species report at http://www.iucnredlist.org .
| SPECIES | CONSERVATION STATUS HISTORY | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 19821 | 19862 | 19882 | 19903 | 19944 | 19955* | 19966 | 20007 | 20033 | 20083 | ||
|
|
− | − | − | − | − | LR | LC | LC | LC |
|
|
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
|
|
− | − | − | − | VU | VU | VU | VU | − | ||
|
|
|
− | − | − | − | VU | EN | EN | EN | − | |
|
|
− | − | − | − | − | VU | VU | VU | − | ||
|
|
− | − | − | − | − | − | − | DD | − |
|
|
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
|
|
VU | VU | VU | VU | VU | EN | VU | VU | VU | ||
|
|
|
− | − | − | − | − | VU | − | − | − | |
|
|
− | − | − | − | − | EN | − | EN | CR | ||
|
|
VU | VU | VU | VU | EN | LR | LC | LC | LC |
|
|
|
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
|
− | − | − | − | VU | VU | VU | VU | VU | ||
|
|
|
− | − | − | − | VU | LR | LC | LC | LC |
|
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
|
|
− | − | − | − | − | VU | VU | VU | LC | ||
|
|
Rare | Rare | Rare | Rare | Rare | VU | VU | VU | NT | ||
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
|
|
− | − | − | − | − | LR | − | LC | LC |
|
|
|
|
|
− | − | − | − | − | LR | − | − | LC |
|
|
|
− | − | − | − | − | LR | − | LC | LC |
|
|
|
|
|
VU | VU | VU | VU | VU | LR | LC | LC | − | |
|
|
− | − | − | − | EN | CR | CR | VU | VU | ||
|
|
− | − | − | − | − | LR | LC | LC | LC |
|
|
|
|
− | − | − | − | − | LR | − | LC | LC |
|
|
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
|
|
VU | VU | VU | EN | EN | VU | VU | VU | VU | ||
|
|
− | − | − | − | − | LR | − | LC | LC |
|
|
|
|
EN | EN | EN | EN | EN | EN | EN | EN | . | ||
|
|
− | − | − | − | − | LR | LC | − | LC |
|
|
Thornback & Jenkins
IUCN Conservation Monitoring Centre
IUCN
Groombridge
Rylands
Baillie &Groombridge
Hilton-Taylor.
Rylands conservation status classification is established according to the Mace-Lande System and is not included in the information available online.
