Amazing technology
Bio-logging consists in attaching onto (or sometimes inserting into) an animal an
electronic device that will record in its memory physical and/or geochemical parameters as a function of time so that scientists can reconstruct the activity of the animal, the characteristics of the environment it travels in and the interactions between the two. This is a pluridisciplinary approach developed by engineers in electronics and
informatics, used by a wide range of scientists from various disciplines, offering
datasets to play with to statistical mathematicians, modellers and data analysts.
Bio-telemetry
A US army-based technology, biotelemetry dates from the 50s and consists in transmitting data from the device to a satellite or a ground station. Since it was made available to non-military users, it has been used for biomedical application and to track animals, especially via the ARGOS system
Bio-logging
Bio-logging differs from biotelemetry in that data are recorded in the memory of the device and as such data collection is not interrupted by signal loss. As such, bio-logging allows users to assemble large, near-continuous datasets of a wide range of data types. However, the animal needs to be captured twice: once for deploying the device and once to recover the device and the precious data it contains. Recently, new bio-loggers combines the benefits of bio-logging with those of biotelemetry as data (or a subset of them) can be transmitted when a window of communication with a satellite or a ground-based station is available.
The bio-logging trade-off
The fundamental trade-off of bio-logging: to try and reduce the size/weight of the logger to diminish the impact on the animal carrying the device, and this while preserving as much as possible the lifetime of the batteries and/or the memory size. Maintaining this balance requires ingeniosity and skills from the developers and users alike.
Bio-logger
There is not one bio-logger!
The shape, functions and characteristics will depend on the type of question the scientists are after. The interaction between developers and users is crucial and there is often – at least during the prototype phase – a strong collaboration between the engineers and the end users to customize devices to the requirements of the field and the scientific question to be addressed.
Three examples
Let’s guide you through typical bio-logging studies with three study cases!
An ecological study of a flying bird, a conservation study of a terrestrial
mammals and a multidisciplinary study case where biologists and physical oceanography scientists meet. Each study will follow roughly the same progression: what is the question, how do we choose the most appropriate loggers, the way to attach the logger, the way data are collected and retrieved, how they are analysed and how the results are disseminated.
This scientific illustration project on bio-logging was made possible thanks to the WWF-UK’s support