
IUCN SSC APES DATABASE
An information service for ape conservation and research.
Introduction
The IUCN APES (Ape Populations, Environments, and Surveys) Database is a unique repository that stores all survey data on ape populations. Its goal is to support ape monitoring, research, and decision-making by compiling a wide range of information on the distribution and dynamics of apes over time. The Database has also begun to compile data on small apes and other primates.
The APES Database is an initiative of the Section on Great Apes (SGA) of the IUCN SSC Primate Specialist Group. It is supported by numerous funding organizations, non-governmental and governmental organizations, and research institutions.
Central to the mission of the APES Database are the following objectives:
-
Identification, compilation, and archival preservation of all existing data on ape population surveys.
-
Dissemination of this data to the ape conservation and research community.
-
Provide regular reports on the status and trends concerning ape populations, habitats, and the threats they encounter.
The APES Database stores a wealth of information detailing the distribution, abundance, and demographics of ape populations across their habitats. This offers a comprehensive understanding of population trends and challenges. By analyzing habitat information and conservation evidence, the Database plays a central role in storing, analyzing, and disseminating critical data. It enables conservationists to make informed decisions, prioritize efforts, and monitor the effectiveness of interventions, ultimately contributing to the survival of critically endangered species. It empowers researchers, conservationists, and policymakers with centralized data for making informed decisions regarding conservation priorities, strategies, and resource allocation. Moreover, the Database actively encourages data sharing and collaboration, fostering a global community dedicated to ape conservation.
The APES Database also serves as a knowledge hub by disseminating information to the public. It raises awareness about conservation challenges and inspires collective action for the preservation of apes.
The success of the APES Database depends on the participation and support of the ape conservation and research community. Researchers, conservation practitioners, and NGOs are invited to contribute their data to this community initiative and to visit the APES website to ensure that their own survey data are listed in the repository.
Archived information in the Database include field survey data (raw datasets including ape nest count data, nest decay data, behavioral data, presence/absence data, and camera trap data), various geospatial layers produced using data deposited in the APES Database or spatial layers produced as secondary products from the raw data archived in the Database, ape literature digital library, taxa range maps, taxa abundance tables, etc.
On the right side of this page, visitors can navigate through the APES Database and find information on data access and release policy, the process to request data from the Database and contribute data to the Database, and access the current report on the content of the APES repository.
For further information and general inquiries, please contact: apes(at)iucnapesportal.org

Database report
A large network of ape conservationists, donors, scientists and experts in this field have helped collect and compile the information you find on this platform. The following numbers give you a brief overview of this effort. A more detailed summary report on the information available through APES you find here. It is updated four times per year. The current numbers are from 2024 March 24.
171 different data providers and 129 participating organizations
time period covered 1989 - 2023
13 ape taxa
482 sites in 26 countries
801 surveys with a total transect length of 6,445,413 km
1,713,157 records
Total number of ape signs: 428,058
425 other species observed with more than 300,000 records
Number of created spatial layers: 14
With APES data published scientific articles: 21
The APES Atlas includes 358 sites with detailed information

Spatial layers
Welcome to the spatial data section of the APES Database.
Here, you can explore several spatial layers created by multiple users using raw survey data stored in our Database. These datasets provide valuable insights into great ape research, including ape range, density distribution, abundance, population genetics, behavioral traits, threats, habitat connectivity, and surveys.
Please contact the data manager for access to specific spatial layers of interest (apes(at)iucnapesportal.org).
Below you will find a map for a spatial overview (the map is currently being expanded). All existing layers are listed in the table below. The complete table including all metadata can be downloaded here.
# | Title | Year | Range | Species | Theme |
|---|---|---|---|---|---|
1 | African apes abundance polygon layers | 2020 | All ape range countries | All ape species | Abundance |
2 | Suitable Environmental Conditions for African great apes | 2012 | All African great ape range countries | Pan troglodytes verus
Pan troglodytes schweinfurthii
Pan troglodytes troglodytes
Gorilla gorilla beringei
Gorilla gorilla diehli
Pan paniscus
Pan troglodytes ellioti | Distribution (probability layer) |
3 | Liberia chimpanzee density | 2014 | Liberia | Pan troglodytes verus | Density distribution |
4 | Liberia biodiversity priority areas | 2015 | Liberia | Pan troglodytes verus | Other |
5 | Great ape species range layers | 2008 | All African great ape range countries | All great ape species | Range |
6 | Updated great ape species range layers | 2016 | All African great ape range countries | All great ape species | Range |
7 | African great ape abundance | 2021 | All African great ape range countries except for Central African Republic; Democratic Republic of the Congo; Liberia; and South Sudan | African great apes excluding bonobos and Grauer's gorillas | Abundance |
8 | Density distribution of western chimpanzees. | 2019 | Senegal
Guinea-Bissau
Mali
Republic of Guinea
Liberia
Sierra Leone
Ivory Coast
Ghana | Pan troglodytes verus | Density distribution |
9 | Occupancy probability of Grauer's gorillas and eastern chimpanzees in DRC. | 2016 | Democratic Republic of Congo | Gorilla beingei graueri | Distribution (probability layer) |
11 | Quantitative estimates of glacial refugia for chimpanzees since the Last Interglacial (120;000 BP) | 2021 | All chimpanzee range countries | Pan troglodytes verus
Pan troglodytes schweinfurthii
Pan troglodytes troglodytes | Distribution (probability layer) |
12 | Range shifts of African apes under global change scenarios | 2021 | All African great ape range countries | All African great ape species | Range |
13 | Threat of mining to African great apes | 2023 | All African great ape range countries except for Central African Republic; Democratic Republic of the Congo; and South Sudan | All African great ape species | Threats |

APES articles
Publications with data from or related to the IUCN SSC APES Database
Arcus Foundation (Ed.). (2018). Infrastructure Development and Ape Conservation (1st ed.). Cambridge University Press. doi: 10.1017/9781108436427
Arcus Foundation (Ed.). (2021a). Killing, Capture, Trade and Ape Conservation (1st ed.). Cambridge University Press. doi: 10.1017/9781108768351
Arcus Foundation (Ed.). (2021b). The Status of Apes: A Foundation for Systematic, Evidence-based Conservation. In Killing, Capture, Trade and Ape Conservation (1st ed., pp. 198–229). Cambridge University Press. doi: 10.1017/9781108768351.009
Barratt, C. D., Lester, J. D., Gratton, P., Onstein, R. E., Kalan, A. K., McCarthy, M. S., … Kühl, H. (2021). Quantitative estimates of glacial refugia for chimpanzees ( Pan troglodytes ) since the Last Interglacial (120,000 BP). American Journal of Primatology, 83(10), e23320. doi: 10.1002/ajp.23320
Carvalho, J. S., Graham, B., Bocksberger, G., Maisels, F., Williamson, E. A., Wich, S., … Kühl, H. S. (2021). Predicting range shifts of African apes under global change scenarios. Diversity and Distributions, 27(9), 1663–1679. doi: 10.1111/ddi.13358
Frazier, A. E., Honzák, M., Hudson, C., Perlin, R., Tohtsonie, A., Gaddis, K. D., … Trgovac, A. B. (2021). Connectivity and conservation of Western Chimpanzee ( Pan troglodytes verus ) habitat in Liberia. Diversity and Distributions, 27(7), 1235–1250. doi: 10.1111/ddi.13270
Freeman, B., Roehrdanz, P. R., & Peterson, A. T. (2019). Modeling endangered mammal species distributions and forest connectivity across the humid Upper Guinea lowland rainforest of West Africa. Biodiversity and Conservation, 28(3), 671–685. doi: 10.1007/s10531-018-01684-6
Ginath Yuh, Y., N’Goran, P. K., Dongmo, Z. N., Tracz, W., Tangwa, E., Agunbiade, M., … Fotang, C. (2020). Mapping suitable great ape habitat in and around the Lobéké National Park, South‐East Cameroon. Ecology and Evolution, 10(24), 14282–14299. doi: 10.1002/ece3.7027
GRASP & IUCN. (2018). GRASP and IUCN report to the CITES Standing Committee on the status of great apes. United Nations Environment Programme Great Apes Survival Partnership, Nairobi, and International Union for Conservation of Nature, Gland. (J. Refisch, S. Wich, & L. Williamson, Eds.). doi: 10.13140/RG.2.2.24454.22085/1
Heinicke, S., Mundry, R., Boesch, C., Amarasekaran, B., Barrie, A., Brncic, T., … Kühl, H. S. (2019). Advancing conservation planning for western chimpanzees using IUCN SSC A.P.E.S.—The case of a taxon-specific Database. Environmental Research Letters, 14(6), 064001. doi: 10.1088/1748-9326/ab1379
Heinicke, S., Ordaz‐Németh, I., Junker, J., Bachmann, M. E., Marrocoli, S., Wessling, E. G., … Kühl, H. S. (2021). Open‐access platform to synthesize knowledge of ape conservation across sites. American Journal of Primatology, 83(1), e23213. doi: 10.1002/ajp.23213
IUCN Species Survival Commission (SSC), Primate Specialist Group. (2020). Regional action plan for the conservation of western chimpanzees (Pan troglodytes verus) 2020–2030. IUCN. doi: 10.2305/IUCN.CH.2020.SSC-RAP.2.en
Kühl, H. S., Sop, T., Williamson, E. A., Mundry, R., Brugière, D., Campbell, G., … Boesch, C. (2017). The Critically Endangered western chimpanzee declines by 80%. American Journal of Primatology, 79(9), e22681. doi: 10.1002/ajp.22681
Ordaz‐Németh, I., Sop, T., Amarasekaran, B., Bachmann, M., Boesch, C., Brncic, T., … Kühl, H. S. (2021). Range‐wide indicators of African great ape density distribution. American Journal of Primatology, 83(12), e23338. doi: 10.1002/ajp.23338
Plumptre, A. J., Nixon, S., Kujirakwinja, D. K., Vieilledent, G., Critchlow, R., Williamson, E. A., … Hall, J. S. (2016). Catastrophic Decline of World’s Largest Primate: 80% Loss of Grauer’s Gorilla (Gorilla beringei graueri) Population Justifies Critically Endangered Status. PLOS ONE, 11(10), e0162697. doi: 10.1371/journal.pone.0162697
Sivaraman, M. R. (2019). State of the Apes: Infrastructure development and Ape conservation. International Journal of Environmental Studies, 76(6), 1050–1054. doi: 10.1080/00207233.2019.1612144
Sop, T., Boesch, C., & Kühl, H. (2019). Western chimpanzee (Pan troglodytes verus). In C. Schwitzer, R. Mittermeier, A. Rylands, F. Chiozza, L. Williamson, D. Byler, … G. McCabe (Eds.), Primates in Peril: The world’s most endangered primates 2018-2020 (pp. 46–49). Retrieved from https://www.globalwildlife.org/wp-content/uploads/2019/10/Primates-in-Peril-2018-2020.pdf
Strindberg, S., Maisels, F., Williamson, E. A., Blake, S., Stokes, E. J., Aba’a, R., … Wilkie, D. S. (2018). Guns, germs, and trees determine density and distribution of gorillas and chimpanzees in Western Equatorial Africa. Science Advances, 4(4), eaar2964. doi: 10.1126/sciadv.aar2964
Tweh, C. G., Lormie, M. M., Kouakou, C. Y., Hillers, A., Kühl, H. S., & Junker, J. (2015). Conservation status of chimpanzees Pan troglodytes verus and other large mammals in Liberia: A nationwide survey. Oryx, 49(4), 710–718. doi: 10.1017/S0030605313001191
Voigt, M., Wich, S. A., Ancrenaz, M., Meijaard, E., Abram, N., Banes, G. L., … Kühl, H. S. (2018). Global Demand for Natural Resources Eliminated More Than 100,000 Bornean Orangutans. Current Biology, 28(5), 761-769.e5. doi: 10.1016/j.cub.2018.01.053
Wich, S. A., Singleton, I., Nowak, M. G., Utami Atmoko, S. S., Nisam, G., Arif, S. Mhd., … Kühl, H. S. (2016). Land-cover changes predict steep declines for the Sumatran orangutan ( Pongo abelii ). Science Advances, 2(3), e1500789. doi: 10.1126/sciadv.1500789
Yuh, Y. G., Dongmo, Z. N., N’Goran, P. K., Ekodeck, H., Mengamenya, A., Kuehl, H., … Elvis, T. (2019). Effects of Land cover change on Great Apes distribution at the Lobéké National Park and its surrounding Forest Management Units, South-East Cameroon. A 13 year time series analysis. Scientific Reports, 9(1), 1445. doi: 10.1038/s41598-018-36225-2

Abundance tables
Welcome to the APES Database section dedicated to abundance estimates of great apes and gibbons! Here, you will find a compilation of abundance estimates gathered from both published and unpublished literature, providing insights into the populations of these primates across various sites. These estimates are categorized into abundance classes, such as 100-300 or 300-500 individuals, giving you an idea of the population size of great apes and gibbons in different locations.
The term 'site' refers to a diverse range of areas, including protected and unprotected regions, logging or mining concessions, or any specific location where a survey has been conducted to assess ape populations. Please follow this link to explore the population estimates of 33 taxa of great and small apes at various sites within their habitats.

Literature data
Welcome to our comprehensive literature Database on great apes!
Here, you will find a wealth of information on chimpanzees, bonobos, gorillas, and orangutans, including scientific articles published in various journals. Additionally, our Database houses numerous reports from field surveys of ape populations, providing valuable insight into their abundance, behaviors, and the threats they face in their habitats.
Please use the drop-down menus below to search for a particular report or publication. You can search by selecting from Country, Site, Taxon, Year, and keywords in the title.
It is important to note that some of the survey reports listed in the literature Database are unpublished and not readily accessible to the public. If you are interested in obtaining these unpublished survey reports, please feel free to reach out to our data manager via email (apes@iucnapesportal.org)
Country | Site | Taxon | Year | Title |
|---|---|---|---|---|
Angola | Maiombe forest | Gorilla gorilla gorilla; Pan troglodytes troglodytes | 2005 | Ron; T. (2005) The Maiombe forest in Cabinda: Conservation efforts; 2000-2004. Gorilla Journal; 30. |
Bangladesh | Sheikh Jamal Inani NP | Hoolock hoolock | 2021 | Kabir; M. T.; Ahsan; M. F.; Cheyne; S. M.; Sah; S. A. M.; Lappan; S.; Bartlett; T. Q.; & Ruppert; N. (2021). Population assessment of the endangered Western Hoolock Gibbon Hoolock hoolock Harlan; 1834 at Sheikh Jamal Inani National Park; Bangladesh; and conservation significance of this site for threatened wildlife species. Journal of Threatened Taxa; 13(7); 18687-18694. |
Bangladesh | Eastern Bangladesh | Hoolock hoolock | 2021 | Naher; H.; Al-Razi; H.; Ahmed; T.; Hasan; S.; Jaradat; A.; & Muzaffar; S. B. (2021). Estimated Density; Population Size and Distribution of the Endangered Western Hoolock Gibbon (Hoolock hoolock) in Forest Remnants in Bangladesh. Diversity; 13(10); 490. |
Burkina Faso | Arly NP; Pama Partial Reserve; Comoe-Leraba Partial Reserve; Koulbi Protected Forest; Nazinga Game Ranch and Reserve | Pan troglodytes verus | 2013 | Ginn; L.P. Robison J.; Redmond; I. and Nekaris; K.A.I.(2013) Strong evidence that the West African chimpanzee is extirpated from Burkina Faso. Oryx; 47:325-326. doi:10.1017/S0030605313000434. |
Burundi | Bururi-Rumonge-Vyanda | Pan troglodytes schweinfurthii | 1989 | Anon. (1989) Developement Rural - Projet Bururi-Rumonge-Vyanda (Burundi). In Proceedings from the first International Workshop for the Conservation and Management of Afromontane Forests; Cyangugu; Rwanda. |
Burundi | 2013 | Hakizimana; D. and Huynen; M-C (2013) Chimpanzee (Pan troglodytes schweinfurthii) Population Density and Abundance in Kibira National Park; Burundi. Pan Africa News; 20(2); December 2013 | ||
Cambodia | Phnom Prich Wildlife Sanctuary | Nomascus gabriellae - Yellow-cheeked crested gibbon | 2009 | Channa; P.; & Gray; T. (2009) The status and habitat of yellow-cheeked crested gibbon Nomascus gabriellae in Phnom Prich Wildlife Sanctuary; Mondulkiri. Phnom Penh: WWF Greater Mekong-Cambodia Country Programme. |
Cambodia | Keo Seima Wildlife Sanctuary (KSWS) | Nomascus gabriellae - Yellow-cheeked crested gibbon | 2022 | Nuttall; M. N.; Griffin; O.; Fewster; R. M.; McGowan; P. J. K.; Abernethy; K.; O'Kelly; H.; Nut; M.; Sot; V.; & Bunnefeld; N. (2022) Long-term monitoring of wildlife populations for protected area management in Southeast Asia. Conservation Science and Practice; 4( 2); e614. https://doi.org/10.1111/csp2.614 |
Cameroon | Ebo Forest | Pan troglodytes ellioti | 2008 | Abwe; E. E.; & Morgan; (2008) The Ebo forest: Four years of preliminary resarch and conservation of the Nigeria-Cameroon chimpanzee (Pan troglodytes vellerosus) Pan Africa News 15 (2). |
Cameroon | Douala-Edea Wildlife Reserve | Pan troglodytes ellioti | 2005 | Ajonina; S.A. (2005) Reproductive and management aspects of endangered chimpanzee (Pan troglodytes) population at Douala-Edea Wildlife Reserve Cameroon. Proposal to Brandenburgische Technische Universitat; Cottbus; Germany. |
Cameroon | FMU 10 030 | Gorilla gorilla gorilla; Pan troglodytes troglodytes | 2003 | Arnhem; E. (2003) Etude de le repartition spatiale des grands mammiferes dans un zone d'etude au centre de l'UFA 10 030. Report PALLISCO; S.A.R.L. |
Cameroon | FMU 10 031 | Gorilla gorilla gorilla; Pan troglodytes troglodytes | 2008 | Arnhem; E. (2008) Eco-Ethological response of great apes and other rainforest mammals to selective logging in Cameroon. PhD thesis. Universite Libre de Bruxelles; Bruxelles. |

Field survey data
Request access to our raw great ape field survey datasets by following the link below. Please be aware that these datasets represent unprocessed field survey data as originally submitted to the IUCN SSC APES database — they have not yet been converted to a standardized format, and datasets with major errors have been temporarily excluded pending cleaning.
The dataset list is continuously updated as new data is submitted and archived datasets are cleaned. A fully standardized format for all datasets is expected by end of 2027. Submitted access requests will be reviewed by the APES database management team, who will then contact you directly.
For inquiries and access facilitation, contact: tenekwetche.sop(at)senckenberg.de

Camera trap data
Camera trap surveys are increasingly used in monitoring programs. In response to this development, it is now possible to store camera trap data in the IUCN SSC APES Database. It is possible to store both image and video material.
Already processed image material including the results in tabular form can be stored in the APES Database as well as data that has not yet been processed.
Optionally, the material can be processed by the Database team using the Zamba-cloud scripts to extract the species recorded on the material and saved alongside the material in tabular form. The results are also sent to the uploader.
The data can be sent to us on a hard drive. We are also working on solutions for an easy upload option.

How can you contribute to the APES Database?
How to share your field survey data with the APES Database?
If you have recent or old ape survey data that you would like to archive in the APES Database, please get in touch with the data manager at apes@iucnapesportal.org. He will be happy to receive your data.
The APES Database is a valuable resource for the ape community, informing ape policy and supporting research and conservation initiatives. The APES Database relies on the contribution of data from all members of the ape community. Therefore, the sharing of data by collectors is crucial for the continuation of the project. In strict respect of the APES data-use policy, archived data can be used by researchers and conservation practitioners for various purposes.
How to obtain data from the APES Database?
Every person can obtain information from the APES Database.
However, the survey data in APES Database are not directly accessible to the public. All archived data remains the property of their owners and their permission must be required before their data can be shared with any third parties.
The main goal of the APES project is to facilitate information sharing among conservationists, field practitioners, scientists, and other stakeholders. Reusing data from the APES Database will contribute to the advancement of ape research and conservation efforts.
If you are interested in obtaining any type of data from the APES Database, such as field survey data, reports/publications, or spatial layers, please follow the steps below:
1. Fill out the 'APES Data request form' or send a request for survey data to the APES data manager (apes@iucnapesportal.org).
Please specify the datasets you are interested in.
2. Provide the name of the person, organization, or institution making the data request.
3. Include a brief description of your project, including its objectives, methodology, and expected outcomes.
4. The data manager will contact the owner(s) of the requested data to seek permission for sharing. Please be patient, as this process may take several days or weeks to receive feedback from the data owners.
·
Citing the APES Database:
If you have used any information from the APES Database, please always use the citation below to acknowledge the data source. You can also support the APES project by creating links to this portal through your websites.
Recommended citation:
Heinicke, S., Mundry, R., Boesch, C., Amarasekaran, B., Barrie, A., Brncic, T., ... & Kühl, H. S. (2019). Advancing conservation planning for western chimpanzees using IUCN SSC APES - the case of a taxon-specific Database. Environmental Research Letters, 14(6), 064001. https://doi.org/10.1002/ajp.23213
Contact
For general inquiries about the IUCN SSC APES Database, please contact the data manager: apes@iucnapesportal.org

Policy
To ensure the integrity of the APES Database, it is essential that all policies regarding the contribution and distribution of ape survey data are completely transparent to all involved parties. The APES Data Access and Release Policy was formulated to regulate all legal and technical details of data contribution and exchange. It consists of four documents which were modeled after the African Elephant Database:
Database Access and Release Policy
This document summarizes and defines the general terms and policies of the Database. Download PDF
APES Database Deposit Form
This form is to be completed by any party contributing data to the APES Database. This form solicits contact information, information about the data set, and specifies any restrictions on access to these data from third parties. Download PDF (English) / Download PDF (French)
APES Database Data Request Document
Any party wishing to access original data sets in the APES Database, must complete this form and also submit a formal research proposal. Each request will be considered by the Data Review Working Group of the APES Database. Download PDF
APES Database Data Users Agreement
This agreement specifies the terms and stipulations of approved data access, relevant only to cases which have been reviewed by the Data Review Working Group. Download PDF
APES Data Template
In addition, this is the standardized APES data template that is used to store all survey data submitted to the APES Database. We do not expect data owners/contributors to arrange their data in this template before submission because of time limitations. Data owners can submit their data in whatever format they are (e.g., tabular, text, shapefile) and the APES Database Team will arrange them according to the APES Template:
Our hope is that this policy makes the APES project as transparent as possible, thereby encouraging data owners to contribute survey data sets to this Database. It is important to emphasize that the data contributor establishes the limits for access to their data set. Some individuals may wish to make data freely available to any request that has been approved by the Data Review Working Group, whereas others may wish to limit data use to the official reports generated by APES.
