| stroke frequencies of emperor penguins diving under sea ice. | during diving, intermittent swim stroke patterns, ranging from burst/coast locomotion to prolonged gliding, represent potential energy conservation mechanisms that could extend the duration of aerobic metabolism and, hence, increase the aerobic dive limit (adl, dive duration associated with onset of lactate accumulation). a 5.6 min adl for emperor penguins had been previously determined with lactate measurements after dives of <50 m depth. in order to assess locomotory patterns during such dives ... | 2002 | 12432000 |
| environmental change and antarctic seabird populations. | recent changes in antarctic seabird populations may reflect direct and indirect responses to regional climate change. the best long-term data for high-latitude antarctic seabirds (adélie and emperor penguins and snow petrels) indicate that winter sea-ice has a profound influence. however, some effects are inconsistent between species and areas, some in opposite directions at different stages of breeding and life cycles, and others remain paradoxical. the combination of recent harvest driven chan ... | 2002 | 12202819 |
| activity time budget during foraging trips of emperor penguins. | we developed an automated method using depth and one axis of body acceleration data recorded by animal-borne data loggers to identify activities of penguins over long-term deployments. using this technique, we evaluated the activity time budget of emperor penguins (n = 10) both in water and on sea ice during foraging trips in chick-rearing season. during the foraging trips, emperor penguins alternated dive bouts (4.8 ± 4.5 h) and rest periods on sea ice (2.5 ± 2.3 h). after recorder deployment a ... | 2012 | 23185608 |
| trace elements and persistent organic pollutants in chicks of 13 seabird species from antarctica to the subtropics. | seabirds from remote regions are mainly exposed to environmental contaminants from non-point contamination of their food webs. pre-fledging seabird chicks are fed by their parents with marine prey captured in the vicinity of breeding colonies. contaminant concentrations in tissues of pre-fledging chicks can thus be mostly related to local dietary sources, and have the potential to unravel spatial patterns of environmental contamination in marine ecosystems. here, mercury (hg), 13 other trace ele ... | 2020 | 31711015 |
| environmental extremes versus ecological extremes: impact of a massive iceberg on the population dynamics of a high-level antarctic marine predator. | extreme events have been suggested to play a disproportionate role in shaping ecological processes, but our understanding of the types of environmental conditions that elicit extreme consequences in natural ecosystems is limited. here, we investigated the impact of a massive iceberg on the dynamics of a population of weddell seals. reproductive rates of females were reduced, but survival appeared unaffected. we also found suggestive evidence for a prolonged shift towards higher variability in re ... | 2012 | 23015628 |
| emperor penguins break their fast with night-time snacks. | | 2018 | 31467434 |
| genetic factors for short life span associated with evolution of the loss of flight ability. | acquisition or loss of flying ability is evolutionarily linked with maximum life span (mls) in mammals and birds. although ecological factors, such as extrinsic mortality, may lead to either shortened or extended life spans through natural selection, mls is influenced by complex molecular and metabolic processes, and the genetic changes associated with flying ability that have led to either a longer or shorter mls are unknown. here, we examine the parallel evolution of flight in mammals and bird ... | 2020 | 32607209 |
| don: deep learning and optimization-based framework for detection of novel coronavirus disease using x-ray images. | in the hospital, a limited number of covid-19 test kits are available due to the spike in cases every day. for this reason, a rapid alternative diagnostic option should be introduced as an automated detection method to prevent covid-19 spreading among individuals. this article proposes multi-objective optimization and a deep-learning methodology for the detection of infected coronavirus patients with x-rays. j48 decision tree method classifies the deep characteristics of affected x-ray corona im ... | 2021 | 33587262 |
| latitudinal, sex and inter-specific differences in mercury and other trace metal concentrations in adélie and emperor penguins in the ross sea, antarctica. | we sought to determine mercury (hg) and other trace metal concentrations in adélie (pygoscelis adeliae) and emperor penguin (aptenodytes forsteri) breast feathers from the ross sea, antarctica, and relate those concentrations to the trophic position and the habitats in which each of these species forage. adélie penguin feathers from the southern ross sea colonies were higher in hg than those sampled further north in the ross sea, potentially due to greater exposure to local sources, such as volc ... | 2020 | 32319892 |
| emperors in hiding: when ice-breakers and satellites complement each other in antarctic exploration. | evaluating the demographic trends of marine top predators is critical to understanding the processes involved in the ongoing rapid changes in antarctic ecosystems. however, the remoteness and logistical complexity of operating in antarctica, especially during winter, make such an assessment difficult. satellite imaging is increasingly recognised as a valuable method for remote animal population monitoring, yet its accuracy and reliability are still to be fully evaluated. we report here the first ... | 2014 | 24963661 |
| blood transcriptome resources of chinstrap (pygoscelis antarcticus) and gentoo (pygoscelis papua) penguins from the south shetland islands, antarctica. | the chinstrap (pygoscelis antarcticus) and gentoo (p. papua) penguins are distributed throughout antarctica and the sub-antarctic islands. in this study, high-quality de novo assemblies of blood transcriptomes from these penguins were generated using the illumina miseq platform. a total of 22.2 and 21.8 raw reads were obtained from chinstrap and gentoo penguins, respectively. these reads were assembled using the oases assembly platform and resulted in 26,036 and 21,854 contigs with n50 values of ... | 2019 | 30929406 |
| phase transitions in huddling emperor penguins. | emperor penguins (aptenodytes forsteri) are highly adapted to the harsh conditions of the antarctic winter: they are able to fast for up to 134 days during breeding. to conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. the effect of different meteorological factors on the huddling behaviour, however, is not well understood. using time-lapse image recordings of an emperor penguin colony, we show that huddling can be described as a phase tr ... | 2018 | 30416209 |
| comparative population genomics reveals key barriers to dispersal in southern ocean penguins. | the mechanisms that determine patterns of species dispersal are important factors in the production and maintenance of biodiversity. understanding these mechanisms helps to forecast the responses of species to environmental change. here, we used a comparative framework and genomewide data obtained through rad-seq to compare the patterns of connectivity among breeding colonies for five penguin species with shared ancestry, overlapping distributions and differing ecological niches, allowing an exa ... | 2018 | 30308702 |
| a well-preserved partial scapula from japan and the reconstruction of the triosseal canal of plotopterids. | the discovery of a well-preserved cranial end of a plotopterid scapula from the early oligocene jinnobaru formation in southwestern japan has provided a fine example of its bone structure and has enabled the reconstruction of the triosseal canal (canalis triosseus) of the unique extinct penguin-like bird. it is believed that plotopterids performed penguin-like underwater propulsion using wings that were similar to those of penguins. until this discovery, the lack of well-preserved plotopterid sc ... | 2018 | 30155348 |
| a buoyancy, balance and stability challenge to the hypothesis of a semi-aquatic spinosaurus stromer, 1915 (dinosauria: theropoda). | a recent interpretation of the fossil remains of the enigmatic, large predatory dinosaur spinosaurus aegyptiacus stromer 1915 proposed that it was specially adapted for a semi-aquatic mode of life-a first for any predatory dinosaur. to test some aspects of this suggestion, a three-dimensional, digital model of the animal that incorporates regional density variations, lungs and air sacs was generated, and the flotation potential of the model was investigated using specially written software. it w ... | 2018 | 30128195 |
| population response of an apex antarctic consumer to its prey and climate fluctuations. | a fundamental endeavor in population ecology is to identify the drivers of population dynamics. a few empirical studies included the effect of prey abundance when investigating simultaneously the effects of density-dependence and climate factors on marine top-predator population dynamics. our aim was to unravel the mechanisms forcing population dynamics of an apex consumer seabird, the south polar skua, using long-term climatic and population time series of the consumer and its prey in terre adé ... | 2019 | 30116877 |
| biophysical characterization of aptenodytes forsteri cytochrome p450 aromatase. | cytochrome p450 19 (cyp19, aromatase) catalyzes the conversion of androgens to estrogens in a sequence of three reactions that each depend on nadph and o2. aromatase is a phylogenetically-ancient enzyme and its breadth of expression in other species has highlighted distinct physiological functions. in songbirds, estrogen production is required for programming the neural circuits controlling song and in the determination of sex in fish and reptiles. this work describes the expression, purificatio ... | 2018 | 29684698 |
| crozier's penguin: an object history of maritime and museum science. | in november 1843 john cassidy, curator in the belfast museum received, perhaps rather dolefully, a collection of bird skins. the museum was barely managing to cope with the constant flow of donations from the 'four quarters of the globe'. but the gift of bird skins could not be ignored. sent by captain francis crozier, recently returned from the british antarctic expedition, the bequest contained 150 species of southern ocean birds, including the remains of two immature 'great penguins'. taking ... | 2018 | 29503030 |
| long-term fasting and re-feeding in penguins. | spontaneous fasting during reproduction (sometimes with a full stomach) and moult is a major characteristic of the annual cycle of penguins. long-term fasting (up to four months in male emperor penguins) is anticipated by the accumulation of fat (incubation fast) and of fat and protein (moult fast). during most of the incubation fast, birds rely almost entirely on lipids as an energy source, body proteins being spared. however, below a critical (but non-total) fat store depletion, marked behavio ... | 2001 | 11246051 |
| bird communication: two voices are better than one. | how do emperor penguins find their mates on a featureless ice flow, packed at densities of ten animals per square meter? a recent study has revealed how use of their 'two-voice' calls enables emperor penguins to locate their mates and chicks under some of nature's most extreme conditions. | 2000 | 10996089 |
| night diving by some emperor penguins during the winter breeding period at cape washington. | all through the bird literature and feature films, there is much ado about dedicated emperor penguin males fasting for 115 days while they do all the incubation of the single egg. sometimes, they may not fast for so long. based on a winter visit to cape washington, we obtained evidence that some birds may feed before the egg is laid, and if they do, and some are males, then their fast is much less than 115 days. the consequence of a shorter fast for the male is a better chance of completing the ... | 2018 | 29317482 |
| the paris agreement objectives will likely halt future declines of emperor penguins. | the paris agreement is a multinational initiative to combat climate change by keeping a global temperature increase in this century to 2°c above preindustrial levels while pursuing efforts to limit the increase to 1.5°c. until recently, ensembles of coupled climate simulations producing temporal dynamics of climate en route to stable global mean temperature at 1.5 and 2°c above preindustrial levels were not available. hence, the few studies that have assessed the ecological impact of the paris a ... | 2020 | 31696584 |
| behavioral changes in fasting emperor penguins: evidence for a "refeeding signal" linked to a metabolic shift. | this study examines the relationships between metabolic status and behavior in spontaneously fasting birds in the context of long-term regulation of body mass and feeding. locomotor activity, escape behavior, display songs, body mass, and metabolic and endocrine status of captive male emperor penguins were recorded during a breeding fast. we also examined whether body mass at the end of the fast affected further survival. the major part of the fast (phase ii) was characterized by the maintenance ... | 1998 | 9530242 |
| heart rates and swim speeds of emperor penguins diving under sea ice. | heart rate during overnight rest and while diving were recorded from five emperor penguins with a microprocessor-controlled submersible recorder. heart rate, cardiac output and stroke volume were also measured in two resting emperor penguins using standard electrocardiography and thermodilution measurements. swim velocities from eight birds were obtained with the submersible recorder. the resting average of the mean heart rates was 72 beats min-1. diving heart rates were about 15% lower than res ... | 1992 | 1588249 |
| morphometric patterns in recent and fossil penguins (aves, sphenisciformes). | a total of 622 skin specimens, 527 skeletons, and myological data compiled by schreiweis (1972) were used to investigate morphometric patterns within and among the 18 recent species of spheniscidae, and to compare the family with a fighted species, the common diving-petrel (pelecanoides urinator), considered by some authorities to be similar to the flighted ancestor of penguins. fossil penguins also were studied using measurements from 111 skeletal elements representing 18 species. most external ... | 1989 | 32336888 |
| sleep changes in emperor penguins during fasting. | the proportion and the distribution over 24 h of the different arousal stages characterized in emperor penguins [wakefulness (w), drowsiness (d), slow-wave sleep (sws), and paradoxical sleep (ps)] were studied under natural ambient conditions in four subjects that were first fed and then deprived of food for 7-18 days. in both fed and fasting states, each arousal stage was distributed through numerous episodes of short duration. the fasting state provoked only a slight increase in d. there was, ... | 1989 | 2916698 |
| protein and lipid utilization during long-term fasting in emperor penguins. | the body mass of male emperor penguins is approximately 38 kg at the beginning of the 4-mo winter fast connected with breeding, and it is an estimated approximately 18 kg in leanest birds at time of spontaneous refeeding. for a 38- to 18-kg range, we investigated the changes in the rate of body mass loss, body composition, and plasma concentrations of uric acid and urea. after the first few days (phase i) a steady state (phase ii) was reached in the proportions of the energy derived from protein ... | 1988 | 3337270 |
| cameratransform: a python package for perspective corrections and image mapping. | camera images and video recordings are simple and non-invasive tools to investigate animals in their natural habitat. quantitative evaluations, however, often require an exact reconstruction of object positions, sizes, and distances in the image. here, we provide an open source software package to perform such calculations. our approach allows the user to correct for perspective distortion, transform images to "bird's-eye" view projections, or transform image-coordinates to real-world coordinate ... | 2020 | 32864407 |
| an electrophysiological and behavioral study of sleep in emperor penguins under natural ambient conditions. | in two pairs of emperor penguins surgically implanted for chronic recordings of eeg, eog and emg, four arousal stages were characterized on the basis of behavioral and electrophysiological criteria: wakefulness (w), drowsiness (d), slow-wave sleep (sws) and paradoxical sleep (ps). the general patterns of electrographic correlates observed for each arousal stage resemble those reported in other birds. sleep patterns were examined with these two pairs placed under natural ambient conditions of lig ... | 1986 | 3786513 |
| resting metabolic rate and cost of locomotion in long-term fasting emperor penguins. | during the antarctic winter emperor penguins fast for up to 120 days when breeding at rookeries, which may be as much as 120 km from open water. emperors have lost almost half of their body mass by the time they walk back to the sea to feed. resting metabolic rate and metabolic rate during treadmill walking at 1.4 km times h-1 were measured regularly along the course of 63-118 days of fasting in four emperors that lost between 33 and 55% of their body mass. resting metabolic rate decreased linea ... | 1980 | 7429912 |
| why the emperor penguin reigns where elephants shiver. | accurate sensing of the environmental temperature is crucial for the survival and wellbeing of organisms. in vertebrates, the cold- and menthol-activated ion channel trpm8 acts as the prime molecular sensor of cool temperatures. by comparing trpm8 in vertebrates with different habitat temperatures, from elephants to penguins, yang et al. identify key residues within the pore domain that determine the channel's cold sensitivity. strikingly, mice engineered to express penguin trpm8 show a remarkab ... | 2020 | 32836018 |
| thermoregulation in fasting emperor penguins under natural conditions. | emperor penguins breed during the cold antarctic winter. the males incubate the single egg while fasting for up to 4 mo and losing some 20 kg of their body mass. fasting captive birds under outdoor conditions lost from 0.145 to 0.434 kg day -1. mean resting metabolic rate, 49.06 w for 24.8 kg body mass, is 7 and 27%, respectively, higher than predicted from general metabolic equations for birds. minimal thermal conductance, 1.31 w m-2 degrees c-1, is within the range for other birds. the lower c ... | 1976 | 970475 |