Theodore Garland

Theodore Garland
University of California, Riverside | UCR · Department of Evolution Ecology and Organismal Biology

BS, MS, PhD

About

445
Publications
62,706
Reads
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36,823
Citations
Introduction
Evolutionary physiology, exercise physiology, quantitative genetics, phylogenetic comparative methods, selection experiments, experimental evolution, ecophysiology, ecological physiology, comparative physiology, physiological ecology, animal behavior.
Additional affiliations
July 2001 - present
University of California, Riverside
Position
  • Professor
August 1987 - August 2001
University of Wisconsin–Madison
Position
  • Professor (Full)
September 1985 - August 1987
University of Washington Seattle
Position
  • PostDoc Position
Education
September 1980 - August 1985
University of California, Irvine
Field of study
  • Ecology and Evolutionary Biology
September 1978 - August 1980
University of Nevada, Las Vegas
Field of study
  • Biology
September 1974 - May 1978
University of Nevada, Las Vegas
Field of study
  • Zoology

Publications

Publications (445)
Article
Full-text available
The movement of limbless terrestrial animals differs fundamentally from that of limbed animals, yet few scaling studies of their locomotor kinematics and morphology are available. We examined scaling and relations of morphology and locomotion in sidewinder rattlesnakes (Crotalus cerastes). During sidewinding locomotion, a snake lifts sections of it...
Article
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Three decades ago, interactions between evolutionary biology and physiology gave rise to evolutionary physiology. This caused comparative physiologists to improve their research methods by incorporating evolutionary thinking. Simultaneously, evolutionary biologists began focusing more on physiological mechanisms that may help to explain constraints...
Article
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Trade-offs and constraints are inherent to life, and studies of these phenomena play a central role in both organismal and evolutionary biology. Trade-offs can be defined, categorized, and studied in at least six, not mutually exclusive, ways. (1) Allocation constraints are caused by a limited resource (e.g., energy, time, space, essential nutrient...
Article
The endocannabinoid (eCB) system in the gut communicates with the body and brain as part of the homeostatic mechanisms that affect energy balance. Although perhaps best known for its effects on energy intake, the eCB system also regulates voluntary locomotor behavior. Here, we examined gut eCB concentrations in relation to voluntary exercise, speci...
Article
While nursing, mammals progress through critical developmental periods for the cardiovascular, musculoskeletal, and central nervous systems. The suckling period in mammals is therefore especially vulnerable to environmental factors that may affect the “developmental programming” of many complex traits. As a result, various aspects of maternal behav...
Article
Skeletal muscles attach to bone at their origins and insertions, and the interface where tendon meets bone is termed the attachment site or enthesis. Mechanical stresses at the muscle/tendon‐bone interface are proportional to the surface area of the bony attachment sites, such that a larger attachment site will distribute loads over a wider area. M...
Article
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Vascular endothelial cells (ECs) sense and respond to hemodynamic forces such as pulsatile shear stress (PS) and oscillatory shear stress (OS). Among the metabolic pathways, glycolysis is differentially regulated by atheroprone OS and atheroprotective PS. Studying the molecular mechanisms by which PS suppresses glycolytic flux at the epigenetic, tr...
Article
Exercise behavior is under partial genetic control, but it is also affected by numerous environmental factors, potentially including early-life experiences whose effects persist into adulthood. We studied genetic and early-life environmental effects on wheel-running behavior in a mouse model that includes four replicate high runner (HR) lines selec...
Article
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Alterations to the gut microbiome caused by changes in diet, consumption of antibiotics, etc., can affect host function. Moreover, perturbation of the microbiome during critical developmental periods potentially have long-lasting impacts on hosts. Using four selectively bred High Runner and four non-selected Control lines of mice, we examined the e...
Article
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Compared with other squamates, snakes have received relatively little ecomorphological investigation. We examined morphometric and meristic characters of vipers, in which both sidewinding locomotion and arboreality have evolved multiple times. We used phylogenetic comparative methods that account for intraspecific variation (measurement error model...
Article
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Ethologically relevant chemical senses and behavioral habits are likely to coadapt in response to selection. As olfaction is involved in intrinsically motivated behaviors in mice, we hypothesized that selective breeding for a voluntary behavior would enable us to identify novel roles of the chemosensory system. Voluntary wheel running (VWR) is an i...
Article
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The maximum amount of oxygen consumed during forced exercise (V̇O2max) sets the upper limit to the effort that can be sustained over relatively long periods and can limit activity levels in nature. Among ectotherms, V̇O2max is primarily affected by body size and body temperature, but it should also coadapt with behavior, ecology, and life history a...
Article
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Selection experiments can elucidate the varying course of adaptive changes across generations. We examined the appendicular skeleton of house mice from four replicate High Runner (HR) lines bred for physical activity on wheels and four non‐selected Control (C) lines. HR mice reached apparent selection limits between generations 17 and 27, running ~...
Article
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Several observational studies have found that the risk for breast cancer is significantly reduced in persons who engage in greater amounts of physical activity. Additional observational studies of breast cancer survivors indicate that greater physical activity before or after diagnosis associates with reduced disease-specific mortality. However, no...
Article
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The biological basis of exercise behavior is increasingly relevant for maintaining healthy lifestyles. Various quantitative genetic studies and selection experiments have conclusively demonstrated substantial heritability for exercise behavior in both humans and laboratory rodents. In the "High Runner" selection experiment, 4 replicate lines of Mus...
Article
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Behavioral addictions can come in many forms, including over-eating, gambling, and over-exercising. All addictions share a common mechanism involving activation of the natural reward circuit and reinforcement learning, but the extent to which motivation for natural and drug rewards share similar neurogenetic mechanisms remains unknown. A unique mou...
Article
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Diving as a lifestyle has evolved on multiple occasions when air-breathing terrestrial animals invaded the aquatic realm, and diving performance shapes the ecology and behaviour of all air-breathing aquatic taxa, from small insects to great whales. Using the largest dataset yet assembled, we show that maximum dive duration increases predictably wit...
Preprint
Full-text available
Ethologically relevant chemical senses and behavioral habits are likely to coadapt in response to selection. As olfaction is involved in intrinsically motivated behaviors in mice, we hypothesized that selective breeding for a voluntary behavior would enable us to identify novel roles of the chemosensory system. Voluntary wheel running (VWR) is an i...
Article
Ecological factors, such as habitat quality, influence the survival and reproductive success of free-living organisms. Urbanization, including roads, alters native habitat and likely influences physiology, behavior, and ultimately Darwinian fitness. Some effects of roads are clearly negative, such as increased habitat fragmentation and mortality fr...
Article
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DNA methylation regulates cell type-specific gene expression. Here, in a transgenic mouse model, we show that deletion of the gene encoding DNA methyltransferase Dnmt3a in hypothalamic AgRP neurons causes a sedentary phenotype characterized by reduced voluntary exercise and increased adiposity. Whole-genome bisulfite sequencing (WGBS) and transcrip...
Article
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In male mammals that provide care for their offspring, fatherhood can lead to changes in behavioral, morphological, and physiological traits, some of which might constitute trade-offs. However, relatively little is known about these changes, especially across multiple reproductive bouts, which are expected to magnify differences between fathers and...
Article
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California mice (Peromyscus californicus) differ from most other mammals in that they are biparental, genetically monogamous, and (compared with other Peromyscus) relatively large. We evaluated effects of cold acclimation on metabolic rate, exercise performance, and morphology of pair-housed male California mice, as well as modulation of these effe...
Article
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Ecophysiology is a relatively recent interdisciplinary field, and although active prior to the 75th anniversary of the American Society of Mammalogists (ASM), it has grown in breadth since then. This growth is in part a result of advances in technology that have reduced the size and improved the portability of key instrumentation, and also made seq...
Article
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The comparative method has long been a fundamental exploratory tool in evolutionary biology, but this venerable approach was revolutionized in 1985, when Felsenstein published “Phylogenies and the Comparative Method” in The American Naturalist. This article forced comparative biologists to start thinking phylogenetically when conducting statistical...
Article
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Indirect genetic effects (IGEs; the heritable influence of one organism on a conspecific) can affect the evolutionary dynamics of complex traits, including behavior. Voluntary wheel running is an important model system in quantitative genetic studies of behavior, but the possibility of IGEs on wheel running and its components (time spent running an...
Article
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Interspecific variation in animal form, function and behaviour is often associated with habitat use, implying co-adaptation. Numerous studies of the 'ecomorphs' of Greater Antillean anoles support this generality, but no other lizard group has shown unambiguous, consistent relationships between limb length and habitat use. We tested for such relati...
Article
Glucocorticoids, a class of metabolic hormones, impact a wide range of traits (e.g., behavior, skeletal growth, muscle maintenance, glucose metabolism), and variation in concentrations of circulating glucocorticoids (such as corticosterone), at the level of natural individual variation, in relation to endocrine disorders, or from exogenous suppleme...
Article
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Mouse lines selectively bred for high voluntary wheel-running behavior are helpful models for uncovering gene networks associated with increased motivation for physical activity and other reward-dependent behaviors. The fact that multiple brain regions are hypothesized to contribute to distinct behavior components necessitates the simultaneous stud...
Data
Extended lists of differentially expressed genes and enriched functional categories. Table A. Extended list of genes exhibiting activity line by brain region interaction effect. Table B. Extended list of clusters of Gene Ontology molecular functions, biological processes, and KEGG pathways enriched among genes exhibiting activity line-by-brain regi...
Article
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abstract: Behavioral ecologists have hypothesized that among- individual differences in resting metabolic rate (RMR) may predict con- sistent individual differences in mean values for costly behaviors or for behaviors that affect energy intake rate. This hypothesis has empirical support and presently attracts considerable attention, but, notably,...
Preprint
Full-text available
Dryad data: http://dx.doi.org/10.5061/dryad.jn33140. abstract: q2 Behavioral ecologists have hypothesized that among-individual differences in resting metabolic rate (RMR) may predict consistent individual differences in mean values for costly behaviors or for behaviors that affect energy intake rate. This hypothesis has empirical support and prese...
Article
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Muscle pH decreases during exercise, which may impair function. Endurance training typically reduces muscle buffering capacity due to changes in fiber type composition, but existing comparisons of species that vary in activity level are ambiguous. We hypothesized that High Runner (HR) lines of mice from an experiment that breeds for voluntary wheel...
Article
Mitochondrial haplotypes have been associated with human and rodent phenotypes, including nonshivering thermogenesis capacity, learning capability, and disease risk. Although the mammalian mitochondrial D-loop is highly polymorphic, D-loops in laboratory mice are identical, and variation occurs elsewhere mainly between nucleotides 9820 and 9830. Pa...
Article
Physical activity is an important component of energy expenditure, and acute changes in activity can lead to energy imbalances that affect body composition, even under ad libitum food availability. One example of acute increases in physical activity is four replicate, selectively-bred High Runner (HR) lines of mice that voluntarily run ~3-fold more...
Article
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We have used selective breeding with house mice to study coadaptation of morphology and physiology with the evolution of high daily levels of voluntary exercise. Here, we compared hindlimb bones and muscle masses from the 11th generation of four replicate High Runner (HR) lines of house mice bred for high levels of voluntary wheel running with four...
Article
Objectives: To use a mouse model to investigate the relationships among the components of the systemic robusticity hypothesis (SRH): voluntary exercise on wheels, spontaneous physical activity (SPA) in cages, growth hormones, and skeletal robusticity, especially cranial vault thickness (CVT). Materials and methods: Fifty female mice from lines a...
Article
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Reproduction strongly influences metabolism, morphology and behavior in female mammals. In species in which males provide parental care, reproduction might have similar effects on fathers. We examined effects of an environmental challenge on metabolically important physiological, morphological, and behavioral measures, and determined whether these...
Article
To explore reward substitution in the context of voluntary exercise, female mice from four replicate high-runner (HR) lines (bred for wheel running) and four non-selected control (C) lines were given simultaneous access to wheels and palatable solutions as competing rewards (two doses of saccharin [0.1, 0.2% w/v]; two doses of common artificial swe...
Article
Objectives: Analyses of bone cross-sectional geometry are frequently used by anthropologists and paleontologists to infer the loading histories of past populations. To address some underlying assumptions, we investigated the relative roles of genetics and exercise on bone cross-sectional geometry and bending mechanics in three mouse strains: high...
Article
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Purpose: Physical activity unquestionably maintains and improves health; however, physical activity levels globally are low and not rising despite all the resources devoted to this goal. Attention in both the research literature and the public policy domain has focused on social-behavioral factors; however, a growing body of literature suggests th...
Article
Among species of lizards, endurance capacity measured on a motorized treadmill is positively related to daily movement distance and time spent moving, but few studies have addressed such relationships at the level of individual variation within a sex and age category in a single population. Both endurance capacity and home range size show substanti...
Article
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Much ecological and evolutionary theory predicts that interspecific interactions often drive phenotypic diversification and that species phenotypes in turn influence species interactions. Several phylogenetic comparative methods have been developed to assess the importance of such processes in nature; however, the statistical properties of these me...
Article
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Much ecological and evolutionary theory predicts that interspecific interactions often drive phenotypic diversification and that species phenotypes in turn influence species interactions. Several phylogenetic comparative methods have been developed to assess the importance of such processes in nature; however, the statistical properties of these me...
Article
Selection experiments and experimental evolution (EE) provide unique opportunities to study the genetics of adaptation because the target and intensity of selection are known relatively precisely. In contrast to natural selection, where populations are never strictly "replicated," EE routinely includes replicate lines so that selection signatures -...
Article
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Animals are constrained by their abilities and by interactions with environmental factors, such as low ambient temperatures. These constraints range from physical impossibilities to energetic inefficiencies, and may entail trade-offs. Some of the constraints related to locomotion and activity metabolism can be illustrated through allometric compari...
Article
Understanding the origin and maintenance of functionally important subordinate traits is a major goal of evolutionary physiologists and ecomorphologists. Within the confines of a limbless body plan, snakes are diverse in terms of body size and ecology, but we know little about the functional traits that underlie this diversity. We used a phylogenet...
Article
Full-text available
Synopsis: Arnold's 1983 path-analytic paradigm, considering "morphology, performance, and fitness," has been elaborated in several ways. For example, current versions recognize the level of "behavior" (including aspects of motivation) as a filter between performance abilities (only measurable if motivation is maximal) and fitness components. Perfo...
Article
Monitoring marine biodiversity is costly and practical solutions have to be implemented to identify species and their preferred habitats, particularly in this era of rapid global change. Citizen science has proven to be effective and with high potential for monitoring efforts, and has been extensively applied to biodiversity. We have used the citiz...