Biologgers can be used to monitor both human and animal physiology and behaviors, activity patterns, and/or environmental stressors. Monitoring of heart rates and rhythms, respiratory patterns, and activity in free-ranging bears can provide unique insights into physiological mechanisms. Such research can also influence the conservation of wildlife, the management of human-wildlife conflicts, and potentially human medicine. Here we describe our experiences with the development and utilization of three generations of implantable biologgers in American black and Eurasian brown bears (Ursus americanus and Ursus arctos arctos). These devices have enabled novel investigations into the underlying mechanisms for winter survival, including the discovery of an extreme respiratory sinus arrhythmias that acts to conserve energy while providing adequate circulation to maintain alertness (i.e., "fight or flight" behaviors). Extreme variations in heart rate have also been documented, including a 33.8s asystole and a 261beats/min sinus tachycardia in black bears and a 39.4s asystole and a 240beats/min sinus tachycardia in brown bears. Long-term data recording has also identified annual trends in heart rates and activity in both species. Combining physiological data with concurrent GPS collar locations provided insights into the impacts of human and environmental stressors (hunting, predation by other bears, road crossings, drones), which would not have been apparent through spatial data analysis alone. More recently, short-range wireless telemetry has allowed for real-time streaming of data via telemetry stations placed in remote den locations. Future iterations include transponders for biomonitoring and as an early warning system to aid in the prevention of poaching in free-ranging animals. In this review, we discuss the primary experimental capabilities of the current and next-generation systems. We highlight device evolution in terms of new physiological measurements (e.g., temperature, activity, impedance, posture), increased data storage capacity, improved wireless capabilities, and miniaturization to reduce the invasiveness of implantation procedures. These biologgers are now being applied to other species, and the possibilities seem limitless as technologies continue to advance.
Bibliographical noteFunding Information:
Black Bear Research: Field work in Wyoming and Colorado was led by Henry Harlow of the University of Wyoming. Assistance with Minnesota fieldwork was provided by Karen Noyce and Brian Dirks of the Minnesota Department of Natural Resources. Brown Bear Research: We are grateful to Sven Brunberg for bear handling and logistics and to Lena Buske and Peter Linde for providing training and participating in the implantations of the first DX devices in Sweden. Technical assistance with the Reveal and Reveal LINQ™ devices was provided by Brian Lee, Eric Zhao, Grant Neitzell, Spencer Hurd, Paul Krause, Traci Washburn, David Washburn, Paul Solheim, Scott Hansohn, Kathryn Chang, and Scott Hawkinson of Medtronic. Assistance with manuscript formatting was provided by Monica Mahre. This work was supported by the Minnesota Department of Natural Resources and the University of Minnesota’s Institute for Engineering in Medicine and Department of Surgery. The Scandinavian Brown Bear Research Project is funded primarily by the Norwegian Environmental Agency, the Swedish Environmental Protection Agency, and the Research Council of Norway. All cardiac monitors were donated by Medtronic.
Black Bear Research: This work was supported by the Minnesota Department of Natural Resources and the University of Minnesota’s Institute for Engineering in Medicine and Department of Surgery. Brown Bears Research: Grants from the Norwegian Directorate for Nature Management, Nordforsk (project no. 44042) and the Lundbeck Foundation (grant nr R126-2012-12408). The Scandinavian Brown Bear Research Project is funded by the Swedish Environmental Protection Agency, the Norwegian Directorate for Nature Management, the Swedish Association for Hunting and Wildlife Management, WWF Sweden and the Research Council of Norway. All cardiac monitors were donated by Medtronic.
© 2018 The Author(s).
Copyright 2018 Elsevier B.V., All rights reserved.
- Autonomic nervous system
- Heart rate
- Respiratory sinus arrhythmia