The objective of this research to develop a GPS-based animal tracking system (Clark ATS), costing less than $1 000 per unit, with spread-spectrum radio frequency communication between collar and base station, real-time collar tracking capabilities, large (up to 8 GB) user-expandable on-board data storage, and very low power demand (mean consumption < 100 mW) and with very high battery capacity (19 AH D-cells) was successfully met. These attributes and capabilities of the Clark ATS should allow the user to economically deploy the system on an adequate sample of animals for up to 3 weeks at a data capture rate of once every minute without the need to re-collect and service the collar. For longer-term deployments, the user could configure the system to acquire data at 15-minute intervals for up to 1 year without service. The real-time tracking capabilities of the Clark ATS should enable researchers to accurately examine animal distribution and activity responses to acute, short-term disturbances relative to longer-term behavioral patterns. Real-time GPS tracking may also provide time- and cost-savings to researchers and natural resource managers attempting to relocate a tagged animal in the field for direct observation or other operations.