Estación de Biología Tropical "Los Tuxtlas", Instituto de Biología, Universidad Nacional Autónoma de México


México occupies a predominant place in the world because of the richness of its mammal fauna, about 450 species. In tropical rain forests, small, medium and large size mammals are particularly sensitive to habitat loss and fragmentation caused by human activity, and their populations are also much impacted by hunting and trafficking. These pressures have resulted in local extinction of populations and species and in remnant populations living under precarious ecological and demographic conditions.


As a result of their cryptic habits and of the fact that many species are nocturnal, little is known about terrestrial mammal populations in tropical rain forests. In addition, most of these mammals are sensitive to the presence of humans in their habitat, further complicating the possibility to study them. The use of camera-traps allows the investigation of terrestrial mammal populations and the study of behavioral aspects of particular species, without interfering with their habits and behavior.


Camera traps permit to investigate terrestrial mammals that also live at low densities, and are useful for recognizing species that are difficult to identify by their tracks or other means. With camera-traps, one can obtain data to estimate population density, to assess activity patterns and habitat use, and to study behavior patterns.


Foto: Didelphis marsupiales (@ O. Cruz)





Our study sites are Los Tuxtlas (southern Veracruz) and Palenque National Park and the Métzabok reserve (in the Lacandon forest in Chiapas). Specifically we are interested in the following:


·        To determine the medium and large size mammals that can be detected with the camera-traps

·        To assess the relationship between capture frequency and diurnal and nocturnal activity

·        To assess the relationship between frequency of capture and general climatic conditions

·        To map over the annual cycle the seasonality of detection of each mammal species captured by the camera-traps




With the use of camera-traps, one can record species that are difficult to observe such as felids, small rodents, and marsupials among others, without disturbing their behaviors.


Tayasu tajacu


Leopardos pardalis

Dasyprocta mexicana


When this technique is complemented with line transects and/or trail sampling and other methods (e.g. tracks), it can provide very accurate and reliable information about the terrestrial mammals present and/or active in a given area. Such studies can be implemented not only for inventories, but also for medium and long term monitoring of the mammal populations. Importantly, the use of camera-traps can be a powerful conservation tool, both at a local and regional levels (remember, a picture is worth a thousand words !).


Agouti paca

Tayasu tajacu

Dasypus novemcinctus


For further information on this program, please contact <[email protected]>

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Copyright @ 2007 Alejandro Estrada

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