Lewis Halsey

Lewis Halsey
University of Roehampton | RU · Department of Life Sciences

Ph. D

About

175
Publications
92,614
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6,150
Citations
Citations since 2017
44 Research Items
3747 Citations
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20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
Introduction
Lewis Halsey is a Professor of Environmental Physiology at the University of Roehampton. He investigates the energetics of a host of mainly vertebrate species, including humans, to answer questions about their energy budgeting, and adaptations for energy efficiency. His current major project is 'The energy management strategies of wild animals'.
Additional affiliations
January 2009 - December 2011
University of Roehampton
September 2007 - December 2015
University of Roehampton
Position
  • Comparative and Environmental Physiologist
January 2002 - December 2008
University of Birmingham

Publications

Publications (175)
Preprint
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[Now in print; published version here: https://www.researchgate.net/publication/348295173_Men_Women_and_STEM_Why_the_Differences_and_What_Should_Be_Done] It is a well-known and widely lamented fact that men outnumber women in a number of fields in STEM. The most commonly discussed explanations for the gender gaps are discrimination and socializatio...
Article
Full-text available
The thermoneutral zone (TNZ) defines the range of ambient temperatures at which resting metabolic rate (MR) is at a minimum. While the TNZ lower limit has been characterized, it is still unclear whether there is an upper limit, that is, beyond which MR during rest increases, and if so, what physiological upregulations explain this. We take the firs...
Article
Full-text available
Understanding the impacts of activity on energy balance is crucial. Increasing levels of activity may bring diminishing returns in energy expenditure because of compensatory responses in non-activity energy expenditures.1, 2, 3 This suggestion has profound implications for both the evolution of metabolism and human health. It implies that a long-te...
Article
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Historic over-exploitation and the more recent threats caused by fisheries by-catch, disease and climate change have left sea turtle populations in the Wider Caribbean at risk of extinction.. In 1995, following regional declines in nesting and foraging populations, the island of Anguilla implemented a moratorium on the hunting of turtles. At the re...
Article
Water is essential for survival, but one in three individuals worldwide (2.2 billion people) lacks access to safe drinking water. Water intake requirements largely reflect water turnover (WT), the water used by the body each day. We investigated the determinants of human WT in 5604 people from the ages of 8 days to 96 years from 23 countries using...
Article
Introduction The thermoneutral zone (TNZ) defines the range of ambient temperatures at which resting metabolic rate is at a minimum without sensible dry heat loss; the body not needing to defend its core temperature. The TNZ has been defined in a number of species yet surprisingly, in humans only its lower limit has been well characterised; indeed,...
Article
Full-text available
In mammals, trait variation is often reported to be greater among males than females. However, to date, mainly only morphological traits have been studied. Energy expenditure represents the metabolic costs of multiple physical, physiological, and behavioral traits. Energy expenditure could exhibit particularly high greater male variation through a...
Article
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Background Locomotion is often a necessity for animal survival and can account for a large proportion of an individual’s energy budget. Therefore, determining the energy costs of locomotion is an important part of understanding the interaction between an animal and its environment. Measures of animal acceleration, specifically ‘dynamic body acceler...
Article
The received wisdom on how activity affects energy expenditure is that the more activity is undertaken, the more calories will have been burned by the end of the day. Yet traditional hunter-gatherers, who lead physically hard lives, burn no more calories each day than Western populations living in labor-saving environments. Indeed, there is now a w...
Preprint
Full-text available
The received wisdom on how activity affects energy expenditure is that the more activity is undertaken, the more calories will have been burned by the end of the day. Yet traditional hunter-gatherers, who lead physically hard lives, burn no more calories each day than western populations living in labour-saving environments. Indeed, there is now a...
Article
Full-text available
Regional endothermy has evolved several times in marine fishes, and two competing hypotheses are generally proposed to explain the evolutionary drivers behind this trait: thermal niche expansion and elevated cruising speeds. Evidence to support either hypothesis is equivocal, and the ecological advantages conferred by endothermy in fishes remain de...
Article
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We respond to El-Hout et al.’s commentary on our paper ‘Men, Women and STEM: Why the Differences and What Should Be Done?’. El-Hout et al. challenge several aspects of the position we present in the paper and outline their recent work on the concept of ‘masculine defaults’: a plausible contributor to the gender gaps found in some STEM fields. For t...
Article
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The archetypal foraging behaviour of tropical seabirds is generally accepted to differ from that of their temperate and polar breeding counterparts, with the former exhibiting less predictable foraging behaviour associated with the less predictable prey of the tropical marine environment. Similarly, temperate and polar species have predictable, ann...
Article
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Extrapolating patterns from individuals to populations informs climate vulnerability models, yet biological responses to warming are uncertain at both levels. Here we contrast data on the heating tolerances of fishes from laboratory experiments with abundance patterns of wild populations. We find that heating tolerances in terms of individual physi...
Article
Full-text available
1. We do not yet have the means to directly measure the energy expenditure of wild animals, particularly at a high temporal resolution. However, we can instead measure factors that correlate with energy expenditure, such as heart rate or accelerometry, i.e. energy expenditure proxies. 2. To estimate the magnitude of differences in energy expenditur...
Article
Full-text available
It is a well-known and widely lamented fact that men outnumber women in a number of fields in STEM (science, technology, engineering and maths). The most commonly discussed explanations for the gender gaps are discrimination and socialization, and the most common policy prescriptions target those ostensible causes. However, a great deal of evidence...
Article
Full-text available
1. Judicious management of energy can be invaluable for animal survival and reproductive success. Capital breeding mammals typically transfer energy to their young at extremely high rates while undergoing prolonged fasting, making lactation a tremendously energy demanding period. Effective management of the competing demands of the mother's energy...
Article
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The Caribbean Island of Anguilla in the north-eastern Lesser Antilles is home to one of the last populations of the Critically Endangered Lesser Antillean iguana Iguana delicatissima. This population is highly threatened primarily because of hybridisation with non-native Iguana iguana. This study assesses the degree of hybridisation between Anguill...
Article
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New findings: What is the central question of this study? Does available comparative data provide empirical evidence that humans are adapted to endurance running at high ambient temperatures? What is the main finding and its importance? Comparing the results of races that pit man against horse, we find that ambient temperature on race day has less...
Article
Movement is a necessary yet energetically expensive process for motile animals. Yet how individuals modify their behaviour to take advantage of environmental conditions and hence optimise energetic costs during movement remains poorly understood. This is especially true for animals that move through environments where they cannot easily be observed...
Article
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Maximum swimming behaviour is rare in the laboratory or the wild, limiting our understanding of the top-end athletic capacities of aquatic vertebrates. However, jumps out of the water - exhibited by a diversity of fish and cetaceans - might sometimes represent a behaviour of maximum burst effort. We collected data on such breaching behaviour for 14...
Article
Shark and ray megafauna have crucial roles as top predators in many marine ecosystems, but are currently among the most threatened vertebrates and, based on historical extinctions, may be highly susceptible to future environmental perturbations. However, our understanding of their energetics lags behind that of other taxa. Such knowledge is require...
Article
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The p-value has long been the figurehead of statistical analysis in biology, but its position is under threat. p is now widely recognized as providing quite limited information about our data, and as being easily misinterpreted. Many biologists are aware of p's frailties, but less clear about how they might change the way they analyse their data in...
Article
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Organisms vary widely in size, from microbes weighing 0.1 pg to trees weighing thousands of megagrams — a 1021-fold range similar to the difference in mass between an elephant and the Earth. Mass has a pervasive influence on biological processes, but the effect is usually non-proportional; for example, a tenfold increase in mass is typically accomp...
Article
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Analysis of some experimental biology data involves linear regression and interpretation of the resulting slope value. Usually, the x-axis measurements include noise. Noise in the x-variable can create regression dilution, and many biologists are not aware of the implications: regression dilution results in an underestimation of the true slope valu...
Article
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We understand little about the energetic costs of flight in free‐ranging birds; in part since current techniques for estimating flight energetics in the wild are limited. Accelerometry is known to estimate energy expenditure through body movement in terrestrial animals, once calibrated using a treadmill with chamber respirometry. The flight equival...
Article
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Inter-specifically, relative energy costs of terrestrial transport vary several-fold. Many pair-wise differences of locomotor costs between similarly-sized species are considerable, and are yet to be explained by morphology or gait kinematics. Foot contact time, a proxy for rate of force production, is a strong predictor of locomotor energy costs a...
Article
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There is considerable interest in why the process of aging varies between individuals, both in humans and other animals. However, in animals, aging in terms of survival (demographic senescence) is understood in considerably more detail than in terms of declines in the body's functional capacity (functional senescence). Oxidative damage is probably...
Article
1.Animals are expected to be judicious in the use of the energy they gain due to the costs and limits associated with its intake. The management of energy expenditure (EE) exhibited by animals has previously been considered in terms of three patterns: the constrained, independent and performance patterns of energy management. These patterns can be...
Article
The obesity epidemic in humans is juxtaposed by observations of passerine birds exhibiting fine-scale body mass regulation. The ecology literature is replete with research into why these animals regulate body weight, citing tradeoffs between competing pressures such as emaciation and predation. Yet studies on the underlying mechanisms of mass regul...
Article
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The fast swimming and associated breaching behaviour of endothermic mackerel sharks is well suited to the capture of agile prey. In contrast, the observed but rarely documented breaching capability of basking sharks is incongruous to their famously languid lifestyle as filter-feeding planktivores. Indeed, by analysing video footage and an animal-in...
Article
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Aerobic scope represents an animal’s capacity to increase its aerobic metabolic rate above maintenance levels (i.e. the difference between standard (SMR) and maximum (MMR) metabolic rates). Aerobic scope data can be presented in absolute or factorial terms (AAS or FAS, respectively). However, the robustness of these calculations to noise or variabi...
Article
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nimals are not subject to tax regimes, so for them there is just one certainty in life – death. During the many conversations I have had with fellow behaviourists and physiologists about the species they study, I have often asked what their species’ primary cause of morbidity is. The response is usually a furrowed brow. Do most simply starve when t...
Article
The redistribution of species has emerged as one of the most pervasive impacts of anthropogenic climate warming, and presents many societal challenges. Understanding how temperature regulates species distributions is particularly important for mobile marine fauna such as sharks given their seemingly rapid responses to warming, and the socio-politic...
Article
The energy savings experienced by fish swimming in a school have so far been investigated in an near-idealised experimental context including a relatively laminar water flow. The effects of explicitly turbulent flows and different group sizes are yet to be considered. Our repeated-measures study is a first step in addressing both of these issues: w...
Article
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The 3Rs - Replacement, Reduction and Refinement - are embedded into the legislation and guidelines governing the ethics of animal use in experiments. Here, we consider the advantages of adopting key aspects of the 3Rs into experimental biology, represented mainly by the fields of animal behaviour, neurobiology, physiology, toxicology and biomechani...
Article
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Quantifying animal energy expenditure during locomotion in the field is generally based either on treadmill measurements or on estimates derived from a measured proxy. Two common proxies are heart rate (ƒH) and dynamic body acceleration (accelerometry). Both ƒH and accelerometry have been calibrated extensively under laboratory conditions, which ty...
Article
Full-text available
Scientists studying the energy expenditure of air-breathing divers are interested in developing a more tractable technique to support their endeavour. Accelerometers instrumented to animals can return a tangible measure of those animals' activity levels, which in some situations correlates with their metabolic rate. However, I argue that reported e...
Article
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The rate at which active animals can expend energy is limited by their maximum aerobic metabolic rate (MMR). Two methods are commonly used to estimate MMR as oxygen uptake in fishes, namely during prolonged swimming or immediately following brief exhaustive exercise, but it is unclear whether they return different estimates of MMR or whether their...
Data
fig. S1. Phylogenetic tree of the relationships between fish species included in the present study. Phylogenetically informed analyses were performed using the phylogenetic generalized least squares (PGLS) method (Grafen, 1989; Martins & Hansen, 1997; Garland & Ives, 2000) was employed via the ape package (Paradis et al., 2004) in R ( www.r‐project...
Data
table S1. Summary of species by lifestyle group (B, benthic; BP, benthopelagic; P, pelagic) reviewed for the analysis of maximum metabolic rate (MMR) and its standardization to 1000 g mass at 20° C (MMR20).
Article
An animal's size is central to its ecology, yet remarkably little is known about the selective pressures that drive this trait. A particularly compelling example is how ancestral apes evolved large body mass in such a physically and energetically challenging environment as the forest canopy, where weight-bearing branches and lianas are flexible, ir...
Article
Full-text available
The tree canopy is an energetically challenging environment to traverse. Along with compliant vegetation, gaps in the canopy can prove energetically costly if they force a route-extending detour. Arboreal apes exhibit diverse locomotion strategies, including for gap crossing. Which one they employ in any given scenario may be influenced by the ener...
Article
Full-text available
Comparative work on animals' costs of terrestrial locomotion has focussed on the underpinning physiology and biomechanics. Often, much of an animal's energy budget is spent on moving around thus there is also value in interpreting such data from an ecological perspective. When animals move through their environment they encounter topographical vari...
Poster
Full-text available
For colonial seabirds, nest site selection generally consists of choosing a suitable location among the wide range of available sites within the colony. Nest site-quality has the potential to influence fitness, by having an effect on breeding performance and output. Thus the selection of an appropriate nest site can be a trait determinant for an in...
Poster
Full-text available
A king penguin colony is loud. Penguins call to find their mate and/or chick, skuas screech and sheathbills quack. The king penguins have extraordinary good auditory abilities and can easily locate their mate within this vast and loud colony (Legagne et al. 1999) . Yet, amidst all these various sounds, the penguins are asleep. Resting and sleeping...
Article
Full-text available
The physiology and behaviour of ectotherms are strongly influenced by environmental temperature. A general hypothesis is that for performance traits, such as those related to growth, metabolism or locomotion, species face a trade-off between being a thermal specialist or a thermal generalist, implying a negative correlation between peak performance...
Data
Appendix S1. Full data set and phylogenetic information.
Article
Full-text available
The energetic costs for animals to locomote on land influence many aspects of their ecology. Size accounts for much of the among-species variation in terrestrial transport costs, but species of similar body size can still exhibit severalfold differences in energy expenditure. We compiled measurements of the (mass-specific) minimum cost of pedestria...
Presentation
Full-text available
A study on sleep and behavioural response of king penguins to predator and non-predator sound stimuli.
Article
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How animals allocate their time to different behaviours has important consequences for their overall energy budget and reflects how they function in their environment. This potentially affects their ability to successfully reproduce, thereby impacting their fitness. We used accelerometers to record time-activity budgets of 21 incubating and chick-r...
Article
Full-text available
The energetic cost of locomotion can be a substantial proportion of an animal's daily energy budget and thus key to its ecology. Studies on myriad species have added to our knowledge about the general cost of animal movement, including the effects of variations in the environment such as terrain angle. However, further such studies might provide di...
Article
Full-text available
Energy management models provide theories and predictions for how animals manage their energy budgets within their energetic constraints, in terms of their resting metabolic rate (RMR) and daily energy expenditure (DEE). Thus, uncovering what associations exist between DEE and RMR is key to testing these models. Accordingly, there is considerable i...
Article
Full-text available
Polar exploration often involves travelling on foot and thus is physically intensive, with long-term excursions typically resulting in weight loss. Few studies have investigated the energy expended under such circumstances. Here, we present a range of prediction equations for estimating metabolic rate from heart rate or accelerometry data for speci...
Article
Full-text available
Rates of aerobic metabolism vary considerably across evolutionary lineages, but little is known about the proximate and ultimate factors that generate and maintain this variability. Using data for 131 teleost fish species, we performed a large-scale phylogenetic comparative analysis of how interspecific variation in resting metabolic rates (RMRs) a...
Article
Full-text available
The effects of unnatural disturbances on the behaviour and energetics of animals are an important issue for conservation and commercial animal production. Biologging enables estimation of the energy costs of these disturbances, but not specifically the effect these costs have on growth; a key outcome measure for animal farming enterprises. We looke...
Article
Full-text available
Returning to the shore after a feeding sojourn at sea, king penguins often undertake a relatively long terrestrial journey to the breeding colony carrying a heavy, mostly frontal, accumulation of fat along with food in the stomach for chick-provisioning. There they must survive a fasting period of up to a month in duration, during which their compl...
Article
Full-text available
We humans know we are not physically fit unless we do extra, voluntary exercise. Yet we have never asked whether the same is true for animals. If it is, then give that energy will be spent keeping fit this raises important issues about new energetic trade-offs, which have never been considered.
Article
Summary of the phylogenetic least squares regression model testing for the effects of thermal performance breadth for aerobic scope (60, 70 and 90% of Pmax), optimal temperature (Topt), body mass (log g) and lifestyle (benthic, benthopelagic, or pelagic) on maximum aerobic scope (Pmax; log mg O2 h-1). N = 28 species.
Article
A) Relationship between model-derived Pmax and maximum aerobic scope (AS) measured in the original study from which data were extracted (Pmax = 0.998(AS) + 3.876; p < 0.001, r2 = 0.996). B) Relationship between model-derived Topt and the maximum temperature (T) at which AS was measured in the original study from which the data were extracted (Topt...
Article
Summary of the phylogenetic least squares regression model testing for the effects of thermal performance breadth for aerobic scope (80 % of Pmax), optimal temperature (Topt), body mass (log g) and lifestyle (benthic, benthopelagic, or pelagic) on maximum aerobic scope (Pmax; log mg O2 h-1). For lifestyle categorisation, the reference category is ‘...
Article
Summary of the phylogenetic least squares regression model testing for the effects of thermal performance breadth for aerobic scope (60, 70 and 90% of Pmax), optimal temperature (Topt), body mass (log g) and lifestyle (benthic, benthopelagic, or pelagic) on maximum aerobic scope (Pmax; log mg O2 h-1). N = 28 species.
Article
A) Relationship between model-derived Pmax and maximum aerobic scope (AS) measured in the original study from which data were extracted (Pmax = 0.998(AS) + 3.876; p < 0.001, r2 = 0.996). B) Relationship between model-derived Topt and the maximum temperature (T) at which AS was measured in the original study from which the data were extracted (Topt...
Article
Summary of the phylogenetic least squares regression model testing for the effects of thermal performance breadth for aerobic scope (80 % of Pmax), optimal temperature (Topt), body mass (log g) and lifestyle (benthic, benthopelagic, or pelagic) on maximum aerobic scope (Pmax; log mg O2 h-1). For lifestyle categorisation, the reference category is ‘...
Article
Data were analysed using the phylogenetic generalised least squares (PGLS) method [1, 2] with the ‘caper’ package [3] in R, applying a phylogeny generated from the comprehensive tree of life [4] using the ‘rotl’ package [5]. The branch lengths in the tree were estimated using Grafen's arbitrary branch lengths transformation [2] (branch lengths set...
Article
Data were analysed using the phylogenetic generalised least squares (PGLS) method [1, 2] with the ‘caper’ package [3] in R, applying a phylogeny generated from the comprehensive tree of life [4] using the ‘rotl’ package [5]. The branch lengths in the tree were estimated using Grafen's arbitrary branch lengths transformation [2] (branch lengths set...
Article
Full-text available
Detailed materials and methods, and explanation and regression figures of re-analysis based on digitisation of Figure 1A in Hanna et al. (2008)
Article
Full-text available
Detailed materials and methods, and explanation and regression figures of re-analysis based on digitisation of Figure 1A in Hanna et al. (2008)
Article
Full-text available
Detailed materials and methods, and explanation and regression figures of re-analysis based on digitisation of Figure 1A in Hanna et al. (2008)
Article
All of us have experimented with holding our breath. Particularly if we are submerged underwater, visceral feelings quickly take hold. Memories of these experiences maybe at the forefront of our minds when we contemplate the extraordinary diving exploits of our air-breathing cousins the seals and whales. Indeed, few topics have exercised the intere...
Article
Full-text available
An animal's movement speed affects all behaviors and underlies the intensity of an activity, the time it takes to complete it, and the probability of successfully completing it, but which factors determine how fast or slow an animal chooses to move? Despite the critical importance of an animal's choice of speed (hereafter designated as "speed-choic...
Data
Appendix S5. R Script for implementing the behavioral assignment method presented.
Data
Appendix S4. Accuracy of assignments for both species and all three behaviours depending on bin size used in the histograms generated to inform behavioural assignments.
Data
Appendix S1. Histograms for calculated metrics of accelerometry from one kittiwake. Appendix S2. Histograms for calculated metrics of accelerometry from one human participant. Appendix S3. Histograms for calculated metrics of accelerometry from one kittiwake after data assigned as flight were removed.