Timothy E Higham

Timothy E Higham
University of California, Riverside | UCR · Department of Biology

PhD

About

162
Publications
41,346
Reads
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3,528
Citations
Citations since 2016
62 Research Items
2227 Citations
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20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Introduction
I am a full professor at the University of California, Riverside. I study comparative biomechanics, functional morphology, and comparative physiology of vertebrate locomotion and feeding.
Additional affiliations
July 2015 - present
University of California, Riverside
Position
  • Professor (Associate)
July 2011 - June 2015
University of California, Riverside
Position
  • Professor (Assistant)
August 2008 - June 2011
Clemson University
Position
  • Professor (Assistant)
Education
August 2006
University of California, Davis
Field of study
  • Molecular, Cellular, and Integrative Physiology
June 2003
University of Cincinnati
Field of study
  • Biology
May 2000
The University of Calgary
Field of study
  • Zoology

Publications

Publications (162)
Article
Full-text available
When predators rely on high-speed movements to capture prey, prey often exhibit traits that result in correspondingly extreme physical performance. Biomechanical studies of these interactions are typically conducted in laboratory settings, thereby eliminating some of the ecological context. We studied how behavioural state, specifically vigilance l...
Article
Full-text available
The remarkable adhesive capabilities of geckos have garnered attention from scientists and the public for centuries. Geckos are known to have an adhesive load-bearing capacity far in excess (by 100-fold or more) of that required to support their body mass or accommodate the loading imparted during maximal locomotor acceleration. Few studies, howeve...
Article
Full-text available
Locomotion and feeding are key axes of diversity among fishes, and these are commonly integrated for successful prey capture. However, little is known about biomechanical variation among highly ecologically divergent populations of fishes. Three-spined stickleback, Gasterosteus aculeatus, is an ideal species for teasing apart the relationships betw...
Article
Full-text available
The evolutionary history of vertebrate locomotion is punctuated by innovations that have permitted expansion into novel ecological niches. Frictional adhesion of geckos is an innovation renowned for enabling locomotion on vertical and inverted smooth surfaces. Much is known about the microstructure and function of the fully-expressed gekkotan adhes...
Article
Full-text available
Speciation is a multifaceted process that involves numerous aspects of the biological sciences and occurs for multiple reasons. Ecology plays a major role, including both abiotic and biotic factors. Whether populations experience similar or divergent ecological environments, they often adapt to local conditions through divergence in biomechanical t...
Article
Full-text available
Many geckos have the remarkable ability to reversibly adhere to surfaces using a hierarchical system that includes both internal and external elements. The vast majority of studies have examined the performance of the adhesive system using adults and engineered materials and substrates (e.g., acrylic glass). Almost nothing is known about how the sy...
Article
Nature provides the parameters, or boundaries, within which organisms must cope in order to survive. Therefore, ecological conditions have an unequivocal influence on the ability of organisms to perform the necessary functions for survival. Biomechanics brings together physics and biology to understand how an organism will function under a suite of...
Article
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The material properties of the cells and tissues of an organism dictate, to a very large degree, the ability of the organism to cope with mechanical stress induced by externally applied forces. It is, therefore, critical to understand how these properties differ across diverse species and how they have evolved. Herein, a large data base (N = 84 spe...
Article
Major shifts in habitat often occur during life history and can have significant impacts on the morphology and function of an animal; however, little is known about how such ecological changes influence the locomotor system of large aquatic vertebrates. Scalloped hammerheads (Sphyrna lewini) are large sharks found in warm temperate and tropical wat...
Article
Major shifts in habitat often occur during life history and can have significant impacts on the morphology and function of an animal; however, little is known about how such ecological changes influence the locomotor system of large aquatic vertebrates. Scalloped hammerheads (Sphyrna lewini) are large sharks found in warm temperate and tropical wat...
Article
Full-text available
Predators that feed on dangerous prey species must evolve mechanisms to reduce the likelihood of injury or death during a predation attempt. Scorpions are prime examples of dangerous prey items for insectivores, because they can inflict a venomous and potentially fatal sting when attacked. Despite this risk, the western banded gecko (Coleonyx varie...
Article
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Arboreal habitats are characterized by a complex three-dimensional array of branches that vary in numerous characteristics, including incline, compliance, roughness, and diameter. Gaps must often be crossed, and this is frequently accomplished by leaping. Geckos bearing an adhesive system often jump in arboreal habitats, although few studies have e...
Article
Animal movement is often largely determined by abiotic conditions of the environment, including substrate properties. While a large body of work has improved our understanding of how different substrate properties can impact locomotor performance and behavior, few of these studies have investigated this relationship during transitions within a sing...
Article
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Body size is a key factor that influences antipredator behavior. For animals that rely on jumping to escape from predators, there is a theoretical trade-off between jump distance and acceleration as body size changes at both the inter- and intraspecific levels. Assuming geometric similarity, acceleration will decrease with increasing body size due...
Article
1) For arboreal lizards, the ability to cling or adhere to the substrate is critical for locomotion during prey capture, predator escape, thermoregulation, and social interactions. Thus, selection on traits related to clinging is likely strong. 2) Correlations between morphology, performance, and habitat use have been documented in arboreal lizards...
Article
The remarkable ability of geckos to adhere to smooth surfaces is often thought of in terms of external structures, including the branching setae that make contact with the surface producing van der Waals forces. Some geckos also exhibit unique movements of the distal segments of the limbs during locomotion and static clinging, including active digi...
Article
Full-text available
Physical principles and laws determine the set of possible organismal phenotypes. Constraints arising from development, the environment, and evolutionary history then yield workable, integrated phenotypes. We propose a theoretical and practical framework that considers the role of changing environments. This 'ecomechanical approach' integrates func...
Article
Among the most specialized integumentary outgrowths in amniotes are the adhesive, scale-like scansors and lamellae on the digits of anoles and geckos. Less well-known are adhesive tail pads exhibited by 21 gecko genera. While described over 120 years ago, no studies have quantified their possible adhesive function or described their embryonic devel...
Article
The ability to glide through an arboreal habitat has been acquired by several mammals, amphibians, snakes, lizards, and even invertebrates. Lizards of the genus Draco possess specialized morphological structures for gliding, including a patagium, throat lappets, and modified hindlimbs. Despite being among the most specialized reptilian gliders, it...
Article
Tails are versatile structures with diverse forms and functions across vertebrates. They are involved in almost all behaviors critical to survival including locomotion, feeding, and predator avoidance. Although the tail’s role in locomotion and stability has been widely studied, its role in prey capture is relatively unknown. Lizards are an ideal s...
Article
Full-text available
The outcomes of predator-prey interactions between endotherms and ectotherms can be heavily influenced by environmental temperature, owing to the difference in how body temperature affects locomotor performance. However, as elastic energy storage mechanisms can allow ectotherms to maintain high levels of performance at cooler body temperatures, det...
Article
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Movements of ectotherms are constrained by their body temperature due to the effects of temperature on muscle physiology. As physical performance often affects the outcome of predator-prey interactions, environmental temperature can influence the ability of ectotherms to capture prey and/or defend themselves against predators. However, previous res...
Article
The general ability of components of an organism to work together to achieve a common goal has been termed integration and is often studied empirically by deconstructing organisms into component parts and quantifying covariation between them. Kinematic traits describing movement are useful for allowing organisms to respond to ecological contexts th...
Article
Among geckos, the acquisition of the adhesive system is associated with several morphological changes of the feet that are involved in the operation of the adhesive apparatus. However, analyses using a comparative framework are lacking. We applied traditional morphometrics and geometric morphometric analysis with phylogenetic comparative methods to...
Article
Geckos are remarkable in their ability to reversibly adhere to smooth vertical, and even inverted surfaces. However, unraveling the precise mechanisms by which geckos do this has been a long process, involving various approaches over the last two centuries. Our understanding of the principles by which gecko adhesion operates has advanced rapidly ov...
Article
The study of gecko adhesion is necessarily interdisciplinary due to the hierarchical nature of the adhesive system and the complexity of interactions between the animals and their habitats. In nature, geckos move on a wide range of surfaces including soft sand dunes, trees, and rocks, but much of the research over the past two decades has focused o...
Article
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Terrestrial animals constantly move in complex habitats that vary both spatially and temporally. The characteristics of these habitats are not only defined by the physical environment, but also the photic environment even though the latter has largely been overlooked. Numerous studies of terrestrial locomotion have examined the role of habitat stru...
Article
Attachment is imperative for many biological functions, such as holding position and climbing, but can be challenged by natural conditions. Adhesive toe pads and claws have evolved in multiple terrestrial lineages as important dynamic attachment mechanisms, and some clades (e.g., geckos) exhibit both features. The functional relationship of these f...
Article
Full-text available
1. The selection pressures that arise from capturing prey and avoiding predators are some of the strongest biotic forces shaping animal form and function. Examining how performance (i.e., athletic ability) affects the outcomes of encounters be- tween free-ranging predators and prey is essential for understanding the determinants of predation succes...
Article
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Many animals exhibit morphological specializations driven by the extreme selective pressure of predation, and understanding how such specializations shape escape behaviours can elucidate the evolutionary context of these morphologies. We examined the kinematics of the evasive leaps of desert kangaroo rats (Dipodomys deserti) during strikes from sid...
Article
Full-text available
Many animals exhibit morphological specializations driven by the extreme selective pressure of predation, and understanding how such specializations shape escape behaviours can elucidate the evolutionary context of these morphologies. We examined the kinematics of the evasive leaps of desert kangaroo rats (Dipodomys deserti) during strikes from sid...
Article
Full-text available
The surfaces of animals, plants and abiotic structures are not only important for organismal survival, but they have also inspired countless biomimetic and industrial applications. Additionally, the surfaces of animals and plants exhibit an unprecedented level of diversity, and animals often move on the surface of plants. Replicating these surfaces...
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
Full-text available
Fishing is a popular and lucrative sport around the world and, in some cases, may contribute to declining fish stocks. To mediate this problem and maintain fish biomass in aquatic ecosystems, catchand- release fishing, whereby a fish is caught and immediately released, has been implemented in many countries. It is unclear whether the injuries to th...
Article
Full-text available
The alteration of form and function through the life of a fish can have profound impacts on the ability to move through water. Although several studies have examined morphology and function in relation to body size, there is a paucity of data for chondrichthyans, an ancient group of fishes. Ratfishes are interesting in that they utilize flapping pe...
Article
Full-text available
Animal locomotion is driven by underlying axial and appendicular musculature. In order for locomotion to be effective, these muscles must be able to rapidly respond to changes in environmental and physiological demands. Although virtually unstudied, muscles must also respond to morphological changes, such as those that occur with tail autotomy in l...
Article
Animals rarely move through their natural habitat without experiencing an environmental perturbation, such as an obstacle or drop in height. However, rapid perturbations due to mass changes are little studied, and these can have significant impacts on the ecology and evolution of animal locomotion due to associated changes in relative muscle mass,...
Article
Full-text available
Sex-specific genetic markers identified using restriction site-associated DNA sequencing, or RADseq, permits the recognition of a species' sex chromosome system in cases where standard cytogenetic methods fail. Thus, species with male-specific RAD markers have an XX/XY sex chromosome system (male heterogamety) while species with female-specific RAD...
Article
Full-text available
Geckos feature a large range of eye sizes, but what drives this phenotypic diversity is currently unknown. Earlier studies point towards diel activity patterns (DAPs) and locomotory mode, but phylogenetic comparative studies in support of the proposed adaptive mode of eye evolution are lacking. Here, we test the hypothesis of DAPs as the driver of...
Article
Full-text available
Animals rarely move through their natural habitat without experiencing an environmental perturbation, such as an obstacle or drop in height. However, rapid perturbations due to mass changes are little studied, and these can have significant impacts on the ecology and evolution of animal locomotion due to associated changes in relative muscle mass,...
Article
Full-text available
Locomotion inextricably links biomechanics to ecology as animals maneuver through mechanically challenging environments. Faster individuals are more likely to escape predators, surviving to produce more offspring. Fast sprint speed evolved several times in lizards, including geckos. However, the underlying mechanisms determining performance await d...
Article
Full-text available
Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elu...
Article
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A central question in biology is how animals successfully behave under complex natural conditions. Although changes in locomotor behaviour, motor control, and force production in relation to incline are commonly examined, a wide range of other factors, including a range of perch diameters, pervades arboreal habitats. Moving on different substrate d...
Article
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Predation plays a central role in the lives of most organisms. Predators must find and subdue prey to survive and reproduce, whereas prey must avoid predators to do the same. The resultant antagonistic coevolution often leads to extreme adaptations in both parties. Few examples capture the imagination like a rapid strike from a venomous snake. Howe...
Article
Full-text available
Locomotion through complex habitats relies on the continuous feedback from a number of sensory systems, including vision. Animals face a visual trade-off between acuity and light sensitivity that depends on light levels, which will dramatically impact the ability to process information and move quickly through a habitat, making ambient illumination...
Article
Full-text available
Autotomy has evolved in many animal lineages as a means of predator escape, and involves the voluntary shedding of body parts. In vertebrates, caudal autotomy (or tail shedding) is the most common form, and it is particularly widespread in lizards. Here, we develop a framework for thinking about how tail loss can have fitness consequences, particul...
Article
Full-text available
By using adhesion, geckos can move through incredibly challenging habitats. However, continually changing terrain may necessitate modulation of the adhesive apparatus in order to maximize its effectiveness over a range of challenges. Behaviorally modulating how the adhesive system is applied can occur by altering the alignment of the foot relative...
Article
Longer hind limbs are often associated with faster maximum sprint speeds measured in the laboratory and sometimes with increased Darwinian fitness in studies of individual variation in natural populations. Limb length may be altered by changing the length of one or all segments, with different functional consequences. Segment length evolution can b...
Article
Full-text available
Background: Terrestrial animals regularly move up and down surfaces in their natural habitat, and the impacts of moving uphill on locomotion are commonly examined. However, if an animal goes up, it must go down. Many morphological features enhance locomotion on inclined surfaces, including adhesive systems among geckos. Despite this, it is not kno...
Article
Full-text available
Speciation is a multifaceted process that involves numerous aspects of the biological sciences and occurs for multiple reasons. Ecology plays a major role, including both abiotic and biotic factors. Whether populations experience similar or divergent ecological environments, they often adapt to local conditions through divergence in biomechanical t...
Article
Full-text available
Speciation is a multifaceted process that involves numerous aspects of the biological sciences and occurs for multiple reasons. Ecology plays a major role, including both abiotic and biotic factors. Whether populations experience similar or divergent ecological environments, they often adapt to local conditions through divergence in biomechanical t...