1. Estimating the metabolic rate of animals in nature is central to understanding physiological, behavioural and evolutionary ecology animals. Doubly labelled water heart-rate methods are most commonly used approaches, but both have limitations that preclude their application some systems. 2. Accelerometry has emerged as a powerful tool for estimating energy expenditure range animals, yet be estimate field aquatic taxa. We combined two-dimensional accelerometry swim-tunnel respirometry...

Summary Body size is a key determinant of metabolic rate, but logistical constraints have led to paucity energetics measurements from large water‐breathing animals. As result, estimating energy requirements fish generally relies on extrapolation rate individuals lower body mass using allometric relationships that are notoriously variable. Swim‐tunnel respirometry the ‘gold standard’ for measuring active rates in animals, yet previous data entirely derived masses <10 kg – at least one...

The evolution of human cognition has been inferred from anthropological discoveries and estimates brain size fossil skulls. A more direct measure would be cerebral metabolic rate, which is proportional to blood flow rate (perfusion). hominin cerebrum supplied almost exclusively by the internal carotid arteries. sizes foramina that transmitted these vessels in life can measured skulls used calculate perfusion rate. Perfusion 11 species ancestors, Australopithecus archaic Homo sapiens ,...

ABSTRACT As the world warms, it will be tempting to relate biological responses of terrestrial animals air temperature. But temperature typically plays a lesser role in heat exchange those than does radiant heat. Under load, can gain even when body surface exceeds However, buffer impacts exposure: burrows and other refuges may block solar fully, but trees agricultural shelters provide only partial relief. For that do so effectively, evaporative cooling used dissipate Evaporative is dependent...

Abstract The thermoregulatory system of homeothermic endotherms operates to attain thermal equilibrium, that is no net loss or gain heat, where possible, under a challenge, and not set‐point any other target body temperature. concept in temperature regulation has been widely misinterpreted, resulting such confusion some thermoregulation specialists have recommended it be abandoned. But the enjoyed resurgence different domain, lizard microclimate selection. We review principles homeotherms,...

Scale sensilla are small tactile mechanosensory organs located on the head scales of many squamate reptiles (lizards and snakes). In sea snakes kraits (Elapidae: Hydrophiinae), these scale presumptive that purportedly function as both mechanoreceptors potentially hydrodynamic receptors capable sensing displacement water. We combined scanning electron microscopy, silicone casting skin quadrate sampling with a phylogenetic analysis to assess morphological variation in postocular scale(s)...

Taylor and Weibel's theory of symmorphosis predicts that structures the respiratory system are matched to maximum functional requirements with minimal excess capacity. We tested this hypothesis in migratory locust, Locusta migratoria, by comparing aerobic capacity jumping muscles morphology oxygen cascade hopping legs using an intraspecific allometric analysis different body mass (M(b)) at selected juvenile life stages. The consumption rate muscle during exercise scales as M(b)(1.02±0.02),...

The discontinuous gas exchange cycle (DGC) is a breathing pattern displayed by many insects, characterized periodic breath-holding and intermittently low tracheal O(2) levels. It has been hypothesized that the adaptive value of DGCs to reduce oxidative damage, with partial pressures (PO(2) ≈ 2-5 kPa) occurring production oxygen free radicals. If this so, insects displaying should continue actively defend PO(2) even when higher than atmospheric levels (hyperoxia). This behaviour observed in...

Abstract Nutrient arteries enter limb bones through discrete foramina on the shafts. They are required for bone remodelling in response to mechanical loading and dynamic forces imposed by locomotion. The cross-sectional area of nutrient foramen femur represents an index blood flow rate shaft thus provides insight into animal’s level activity. Morphometric data femoral length, mass size from 100 extant bird species eight extinct moa were analysed allometrically phylogenetically. (Qi) (Mf)...

Abstract The stocky skeletons and post-cranial anatomy of many extinct kangaroos indicate that they might have engaged in varied locomotor behaviors, rather than bipedal hopping, as their primary mode locomotion. This study investigates support for this idea by estimating femoral bone perfusion, which is a correlate intensity, compared to living hopping species. Femur blood flow rates can be estimated from the sizes nutrient foramina on femur shaft species, without preservation soft tissue....

Abstract Background Monitoring blood oxygenation is essential in immobilised rhinoceros, which are susceptible to opioid-induced hypoxaemia. This study assessed the reliability, clinical performance and trending ability of Nonin PalmSAT 2500 A pulse oximeter’s Masimo Radical-7 co-oximeter’s dual-wavelength technology, with their probes placed at two measurement sites, inner surface third-eyelid scarified ear pinna white rhinoceroses. Eight rhinoceros were etorphine-based drug combinations...

ABSTRACT A prevailing assumption in the cardiovascular field is that metabolic rate of heart a constant proportion mammal's whole-body aerobic rate. In this Commentary, we assemble previously published cardiovascular, and body mass data from matched terrestrial mammalian species, at rest during heavy exercise, reveal scaling relationships challenge assumption. Our analyses indicate fractional cost systemic perfusion compared with increases significantly size among resting mammals, ∼2.5%...

SUMMARY The hemimetabolous migratory locust Locusta migratoria progresses through five instars to the adult, increasing in size from 0.02 0.95 g, a 45-fold change. Hopping locomotion occurs at all life stages and is supported by aerobic metabolism provision of oxygen tracheal system. This allometric study investigates effect body mass (Mb) on consumption rate (, μmol h–1) establish resting metabolic (), maximum during hopping () muscles first instar, third fifth instar adult locusts. Oxygen...

The evolution of primates involved increasing body size, brain size and presumably cognitive ability. Cognition is related to neural activity, metabolic rate blood flow the cerebral cortex. These parameters are difficult quantify in living animals. This study shows that it possible determine cortical perfusion from internal carotid artery foramina skulls certain mammals, including haplorrhine diprotodont marsupials. We combined both arteries as a proxy metabolism 34 species (0.116-145 kg...

Bipedal hopping is used by macropods, including rat-kangaroos, wallabies and kangaroos (superfamily Macropodoidea). Interspecific scaling of the ankle extensor muscle-tendon units in lower hindlimbs these bipeds shows that peak tendon stress increases disproportionately with body size. Consequently, large store recover more strain energy their tendons, making efficient, but tendons are at greater risk rupture. This first intraspecific analysis on functional morphology (gastrocnemius,...

Summary Weibel and Taylor's theory of symmorphosis predicts that the structural components respiratory system are quantitatively adjusted to satisfy, but not exceed, an animal's maximum requirement for oxygen. We test this in adult migratory locust Locusta migratoria by comparing aerobic capacity hopping flight muscle with morphology oxygen cascade. Maximum uptake during tethered-flight is 967 ± 76 μmol h-1 g-1 (body mass-specific, 95% CI), whereas muscles consume a 158 8 jumping. The...

Flying insects achieve the highest mass-specific aerobic metabolic rates of all animals. However, few studies attempt to maximise cost flight and so many estimates could be sub-maximal, especially where have been tethered. To address this issue, oxygen consumption was measured during tethered in adult locusts Locusta migratoria, some which had a weight attached each wing (totalling 30-45% body mass). Mass-specific rate increased from 28±2 μmol O(2) g(-1) h(-1) at rest 896±101 O(2)g(-1)...

Interspecific studies of adult mammals show that heart mass (Mh, g) increases in direct proportion to body (Mb, kg), such Mh ∝ Mb1.00. However, intraspecific on at different stages development reveal considerable variation between species, Mb0.70–1.00. Part this may arise as a result the narrow size range growing placental mammals, from birth adulthood. Marsupial are born relatively small and offer an opportunity examine ontogeny over much broader range. Data 29 western grey kangaroos...

Abstract Predators play a crucial role in the structure and function of ecosystems. However, magnitude this is often unclear, particularly for large marine predators, as predation rates are difficult to measure directly. If relevant biotic abiotic parameters can be obtained, then bioenergetics modelling offers an alternative approach estimating rates, provide new insights into ecological processes. We integrate demographic data apex predator, broadnose sevengill shark Notorynchus cepedianus...

Birds exhibit wide variation in their use of aquatic environments, on a spectrum from entirely terrestrial, through amphibious, to highly aquatic. Although there are limited empirical data hearing sensitivity birds underwater, mounting evidence indicates that diving detect and respond sound suggesting some modifications the ear may assist foraging or other behaviors below surface. In air, tympanic middle acts as an impedance matcher increases pressure decreases vibration velocity between...