An overview of behavioral, physiological, and environmental sensors used in animal biotelemetry and biologging studies

Abstract

Background: The ability to remotely monitor the behavior of animals and their interactions with their environment has revolutionized how ecologists conduct studies. The creative use and placement of sensors on both biologging and biotelemetric platforms can greatly expand the amount of information that can be garnered from ecological studies. Results: Sophisticated transmitters and data loggers, which once were built by the biologists that used them, are available off the shelf from many commercial manufacturers. The ability to purchase a wide variety of electronic tags has allowed for a wider adoption of electronic tags across ecology, but has resulted in many biologists utilizing them with little understanding of how they function. The purpose of this review is to provide a reader-friendly description of the many sensors available to monitor the behavior, physiology, and environment of both terrestrial and aquatic animals. Our approach here is firstly to describe the electrical and mechanical principles behind each type of sensor and secondly to present one or two classic examples of how they have been used to provide insights into the biology of species from a diversity of taxa. Behavioral sensors that record the speed, acceleration, tilt angle, and direction of movement of an animal as well as its swimming depth or flight altitude will be described. Additional sensors are mentioned that detect feeding and spawning behavior as well as the proximity to conspecifics, prey, and predators. Physiological sensors will be described that monitor muscular, sensory, brain, gastric activity as well as body temperature, and sound production. Environmental sensors will be described that measure irradiance, dissolved oxygen, and magnetic field intensity. It is our hope that this review serves as springboard for biologists to develop innovative ways to learn more about their subjects using the myriad sensors that are available today, and the exciting new sensors to be developed in the future.