Project: Individual behavioral variation in tamandua anteaters in Panama

 


Introduction:

Tropical mammals are understudied relative to temperate-zone mammals and are also at higher risk of extinction due to growing pressure on natural resources in developing tropical countries.  Predicting the response of a population to habitat loss or change requires a thorough understanding of habitat requirements, which in turn relies on knowledge about individual movement and use of space.

Anteaters are a specialized guild of insect-eating mammals native to Central and South America and they have a combination of morphological, physiological and behavioral traits found in no other group of living mammals.  The unusual appearance of all four species of anteaters has made them the subject of considerable curiosity and some research, but no one knows how free-ranging behavior determines habitat requirements and population structure. The tamandua (Tamandua mexicana) is the only anteater that appears to be equally at home on the ground as well as in the trees of tropical forests.  An early study described feeding behavior and seasonal variation in food preferences, but relatively little is known about home ranges or social structure of tamandua populations.  Anteater populations are vulnerable to extirpation as tropical forests and grasslands are converted to croplands and cattle ranches, therefore, it is critical to obtain data on wild anteaters to assist in population monitoring and conservation planning.

Objective:

The objective of this study is to generate a detailed description of the movement patterns of free-ranging northern tamandua anteaters.  This information will be used to determine individual and population-typical patterns of activity, habitat use, and home range size.  Tissue samples are being collected for future genetic analyses of relatedness and degree of inbreeding relative to mainland tamanduas. 

free-ranging T. mexicana on Barro Colorado Island, Panama with radio/GPS/Accelerometer telemetry tag glued to lower back. Photo by D. Brown
Fig. 1. Free-ranging tamandua anteaters on Barro Colorado Island, Panama with radio/GPS/accelerometer telemetry tag glued to lower back. Photos by D. Brown

Methods:

Barro Colorado Island (BCI) has a unique system set up for remote monitoring of wildlife.  The Automated Radio Telemetry System (ARTS) consists of seven 40-m steel towers situated around the island. Each tower has a fixed array of directional antennas and an automated receiving unit.  These receivers record the relative positions of transmitters worn by study animals and transmit these data via a wireless network to a server at the BCI research station (Crofoot et al 2008).  I plan to tag 20 northern tamanduas (30-50% of the total estimated island population) and monitor them with a combination of ARTS and direct observations.

Each anteater will be fitted with a glue-on telemetry device that contains a radio transmitter, a GPS module, and an accelerometer which measures changes in body orientation along three axes simultaneously (Fig. 1).  Tags are programmed to record location every 15 minutes and orientation every 2 minutes, and data will be collected for up to 3 weeks on each animal.

Progress:

In July 2008, I tested two alternative glue-on attachment methods for the tracking device on a captive tamandua at the Memphis Zoo.  With the more successful method, the tag remained in place for five days before falling off.

October-December 2008: three animals were caught, tagged, and monitored.  Two animals kept their tags for 2 and 3 weeks, respectively, allowing for home range estimation and behavioral observations.

April-June 2009: As of June 1, four additional animals have been caught, tagged, and monitored.  Three animals kept their tags for 8,13, and 17 days respectively, allowing for home range estimation and behavioral observations.

Personnel:

Danielle Brown, M.S. (lead)

Roland Kays, Ph.D.
Curator of Mammals, New York State Museum

Martin Wikelski, Ph.D.
Director, Max Planck Institute for Ornithology

Franz Kümmeth
Engineer, E-OBS digital telemetry

Tom Hahn, Ph.D.
Dept. of Neurobiology, Physiology, & Behavior, University of California, Davis

Pete Klimley, Ph.D.
Department of Wildlife, Fish, & Conservation Biology, University of California, Davis

Funding Sources:

NSF Graduate Research Fellowship; University of California Eugene Cota-Robles Graduate Fellowship; Max Planck Institute

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