Future trends in measuring physiology in free-living animals

Abstract

Thus far, ecophysiology research has predominantly been conducted within controlled laboratory-based environments, owing to a mismatch between the recording technologies available for physiological monitoring in wild animals and the suite of behaviours and environments they need to withstand, without unduly affecting subjects. While it is possible to record some physiological variables for free-living animals using animal-attached logging devices, including inertial-measurement, heart-rate and temperature loggers, the field is still in its infancy. In this opinion piece, we review the most important future research directions for advancing the field of ‘physiologging’ in wild animals, including the technological development that we anticipate will be required, and the fiscal and ethical challenges that must be overcome. Non-invasive, multi-sensor miniature devices are ubiquitous in the world of human health and fitness monitoring, creating invaluable opportunities for animal and human physiologging to drive synergistic advances. We argue that by capitalizing on the research efforts and advancements made in the development of human wearables, it will be possible to design the non-invasive loggers needed by ecophysiologists to collect accurate physiological data from free-ranging animals ethically and with an absolute minimum of impact. In turn, findings have the capacity to foster transformative advances in human health monitoring. Thus, we invite biomedical engineers and researchers to collaborate with the animal-tagging community to drive forward the advancements necessary to realize the full potential of both fields. This article is part of the theme issue ‘Measuring physiology in free-living animals (Part II)’.

Heart rate as a measure of emotional arousal in evolutionary biology

“…In this review, I have presented research applying different biologging technology, ranging from fully implantable transmitters to wearable heart rate belts that can be applied non-invasively (table 1). Different technology makes measuring heart rate possible in a wide range of species [107,116], including fish [51], marine mammals and turtles [28,95], domestic pets and farmed animals [33], but different approaches have specific social, ethical and regulatory challenges [117]. For example, implanting transmitters is an invasive process and might not be ethically acceptable in all contexts and species.…”

A Physio-Logging Journey: Heart Rates of the Emperor Penguin and Blue Whale

“…Movement artifact and diminution of the ECG signal by saltwater may be prevented or minimized with further electrode modifications and use of capacitative ECG electrodes ( Ha et al, 2014 ; Reyes et al, 2014 ; Thap et al, 2016 ; Tripathi et al, 2017 ). In addition, detection of heartbeats may be achieved with different noninvasive approaches, including acoustics, near-infrared spectroscopy, photoplethysmography, and nanotechnology ( Burgess et al, 1998 ; McKnight et al, 2019 ; dos Santos et al, 2021 ; Williams et al, 2021b ). Equally important is the continued refinement of data processing and analysis.…”

Introduction to the theme issue: Measuring physiology in free-living animals

“…By introducing the field of biologging to medical biotechnology and sports wearables, as well as technology used in managed animals (agriculture and aquaculture), the hope is that the field can be opened up to allow more researchers to ask the sorts of questions that are required to tackle the most important threats to wild animals (e.g. disease transmission, climate change, [65]). Moreover, because devices developed for the medical biotechnology, agricultural and sports industries are underlined by enormous market opportunity, they are generally better tested and thus have a lower failure rate (e.g.…”

“…This means that animal researchers employing these technologies could get more accurate and reliable data over longer periods of time, which would undoubtedly improve wildlife management, threat mitigation and our understanding of species resilience. This would represent a considerable step forward for wild animal research [65,66]. At the same time, automated analytical and software approaches will increase the power of analyses while also transforming potentially complex physiologging technologies into more userfriendly systems [67].…”