PMID(sorted ascending)
[the fast of the emperor penguin (aptenodytes patagonica j.f. miller) on the isle of the possession (46 degrees 25' south, 51 degrees 045' east].during the fast, ponderal decrease and energy expenditure of captive king penguins are minimal for the incubating adults, and maximal for the moulting birds who are producing their new plumage and whose insulation is reduced at that time. whatever their conditions, the slope of the ponderal decrease curve is uniform before reaching a critical zone. on the other hand, it is independent of the seasons for the unemployed birds.1975808325
[the energy metabolism of the emperor penguin (aptendodytes patagonica j. f. miller) in ambient natural conditions].in natural ambient conditions at possession island the resting metabolism of the emancipated king penguin is 50.40 kcal/kg/d. a bird whose insulation is good and which maintains its stomachic temperature at a high level can reduce its heat production by 42% during the long fasting periods which characterize its reproductive cycle, in particular by social and individual thermoregulating behaviour.1976816534
[use of energy reserves during the breeding fast of the emperor penguin, aptenodvtes forsteri].during the breeding fasting of the emperor penguin, the lipid and protein stores are steadily used to meet the metabolic needs; they represent respectively 93 and 7% of the energy production in the animal. the role of the glucid stores are quantitively negligible. loss of tissue water represents 35,3% of body weight loss. increased weight loss below 20 kg a "critical weight", is associated with a conversion to protein catabolism when lipid supplies are exhausted. these results allow the estimati ...1976816554
[weight loss during the 1st days of fasting in the emperor penguin (aptenodytes forsteri)].in emperor penguins in their breeding colony a 45% decrease in the daily change in body mass was observed during the two first days of fasting. this decrease amy be attributed to the transition to an economical level of energy expenditure.1976826346
fatty acid composition of emperor penguin (aptenodytes forsteri) lipids. 1977830478
effect of glucagon and insulin on plasma free fatty acids and glucose in the emperor penguin, aptenodytes forsteri. 1977892412
energy expenditure for thermoregulation and locomotion in emperor penguins.during the antarctic winter emperor penguins (aptenodytes forsteri) spend up to four mo fasting while they breed at rookeries 80 km or more from the sea, huddling close together in the cold. this breeding cycle makes exceptional demands on their energy reserves, and we therefore studied their thermoregulation and locomotion. rates of metabolism were measured in five birds (mean body mass, 23.37 kg) at ambient temperatures ranging from 25 to -47 degrees c. between 20 and -10 degrees c the metabol ...1976970474
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 ...1976970475
[variation in free amino acid concentration in plasma during the reproductive cycle in the emperor penguin (aptenodytes forsteri)]. 19751139879
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 ...19921588249
daily pattern of melatonin secretion in an antarctic bird, the emperor penguin, aptenodytes forsteri: seasonal variations, effect of constant illumination and of administration of isoproterenol or propranolol.daily variations in circulating melatonin concentrations have been measured at monthly intervals from april to december 1986 in an antarctic bird, the emperor penguin, aptenodytes forsteri, maintained under natural conditions. both duration of the elevated nighttime melatonin levels and amplitude of the day-night rhythm displays an annual variation closely related to variations in the daylength. duration of the nocturnal peak of melatonin secretion depended upon the duration of the darkness, dec ...19911783270
the use of body mass loss to estimate metabolic rate in fasting sea birds: a critical examination based on emperor penguins (aptenodytes forsteri).1. the validity of the body mass loss (bml) method to estimate incubation and molting metabolic rate (mr) in sea birds is examined on the basis of data in emperor penguins (aptenodytes forsteri). 2. the bml composition of emperors during mid incubation is revised (61.7% fat, 5.9% protein and 32.4% water; energy equivalent of bml = 25.5 kj/g). 3. using these data in short-term fasting petrels and penguins, or with bml obtained at the beginning or at the end of the fast in long-term fasting specie ...19882901305
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, ...19892916698
the effect of severe starvation and captivity stress on plasma thyroxine and triiodothyronine concentrations in an antarctic bird (emperor penguin).the effect of confinement and severe starvation on the plasma thyroxine (t4) and triiodothyronine (t3) concentrations was determined in emperor penguins (aptenodytes forsteri). during their annual cycle, emperor penguins fast freely for periods of up to 4 months and may thus represent a unique subject to study endocrine adaptations to fasting. plasma t4 concentrations progressively decreased following capture and confinement of naturally fasting penguins, and within 15-20 days stabilized at leve ...19892920894
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 ...19883337270
[morphologico-functional study of the locomotor system of penguins as a principle of the general motor model of "underwater flight." ii].based on the statements in part i according to the evolution of the underwater flight, its biophysical consequences and summarizing our knowledge on swimming performances of penguins, the active and passive apparatus of movement was studied by dissection of 26 individuals of pygoscelis papua, p. antarctica, p. adeliae, eudyptes chrysolophus, and aptenodytes forsteri. besides the functional explanation of the articulatio sternocoracoidea (diverging considerably from the usual type in birds), a ne ...19863569810
the endocrine control of reproduction and molt in male and female emperor (aptenodytes forsteri) and adelie (pygoscelis adeliae) penguins. i. annual changes in plasma levels of gonadal steroids and lh.changes in plasma lh, testosterone, and estrogens were investigated throughout reproduction and molt in free-living male and female emperor (aptenodytes forsteri) and adelie (pygoscelis adeliae) penguins. in both sexes and species, plasma lh and gonadal steroids were severalfold above basal level at the time of arrival on the breeding grounds, suggesting that environmental cues (especially decreasing daylength in emperors) rather than mating and courting primarily stimulate gonadal development a ...19863781216
the endocrine control of reproduction and molt in male and female emperor (aptenodytes forsteri) and adelie (pygoscelis adeliae) penguins. ii. annual changes in plasma levels of thyroxine and triiodothyronine.changes in plasma thyroxine (t4) and triiodothyronine (t3) levels were studied during a breeding season and in more detail during the postbreeding molt in male and female emperor (aptenodytes forsteri) and adelie (pygoscelis adeliae) penguins under natural conditions in the antarctic. during the 4-month natural fast that accompanies courtship and incubation in male emperors, plasma t4 and t3 levels were maintained around 11 and 0.6 ng/ml, respectively. in courting, fasting female emperors plasma ...19863781233
an electrophysiological and behavioral study of sleep in emperor penguins under natural ambient 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 ...19863786513
[morphologic-functional study of the locomotor system of penguins as a general model of movement in under-water flight. i].regarding several theories of the evolution of the sphenisciformes the specific morpho-physiological alterations for the changeover from aerial to underwater life are discussed. the peculiarities in the penguin's "construction" become comprehensible as strong adjustments to the subaquatic locomotion. surely they took their origin from the equipment of flying birds. the present data of the kinematics of the underwater locomotion show, that propulsion is produced in the same principal way by the f ...19863803859
isolation and characterization of chicken (gallus gallus) and penguin (aptenodytes forsteri) myoglobins. 19724654832
penguin hemoglobin (aptenodytes forsteri). a 45 residue n-terminal sequence. 19734747605
penguin (aptenodytes forsteri) myoglobin. a 70 residue n-terminal sequence. 19734763336
the isolation of a psittacosis-lymphogranuloma venereum (pl) agent from an emperor penguin (aptenodytes forster) chick. 19685696496
glucose and lactate kinetics and interrelations in an antarctic bird (emperor penguin).the isotope single-injection method was used to investigate the glucose and lactate kinetics and the interrelationships between the glucose and lactate pools in fasting emperor penguins. in these remarkably fast-resistant birds, mean lactate concentration, replacement rate, pool, space, and transit time were 1.5 mmol.1-1,53, 900, 60% of body mass, and 17 min, respectively. mean glucose concentration, replacement rate, pool, space, and transit time were 20 mmol.1-1, 23 ...19827081471
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 ...19807429912
emperor penguin oxygen consumption, heart rate and plasma lactate levels during graded swimming exercise.oxygen consumption (vo2), heart rate and blood chemistry were measured in four emperor penguins, aptenodytes forsteri (gray), during graded swimming exercise. the maximum vo2 obtained, 52 ml o2 kg-1 min-1, was 7.8 times the measured resting vo2 of 6.7 ml o2 kg-1 min-1 and 9.1 times the predicted resting vo2. as the swimming effort rose, a linear increase in surface and submerged heart rates (fh) occurred. the highest average maximum surface and submersion heart rates of any bird were 213 and 210 ...19947964411
adaptation to extreme environments: structure-function relationships in emperor penguin haemoglobin.the functional properties of the single haemoglobin (hb) of emperor penguin (aptenodytes forsteri) have been investigated at different temperatures as a function of proton and organic phosphate concentration. the complete amino acid sequence has been established. comparison with that of human hba shows 12 substitutions in the contact regions of alpha beta dimers. in addition to overall similarities shared with most of the avian hbs previously described, this hb shows significant differences, whi ...19948158641
diving behaviour and haemoglobin function: the primary structure of the alpha- and beta-chains of the sea turtle (caretta caretta) and its functional implications.the amino acid sequence of the alpha- and beta-chains of haemoglobin (hb) from the loggerhead sea turtle (caretta caretta) has been determined. comparison with that of human hb shows differences in several residues involved in both alpha 1 beta 1 and alpha 1 beta 2 packing contacts. on the whole, in spite of the mutations, the essential characteristics of both interfaces seem to be maintained. the functional properties of the sea turtle hb have been investigated at different temperatures and as ...19968670176
what parameters can be used for individual acoustic recognition by the greater flamingo?the greater flamingo phoenicopterus ruber is a colonial bird for which acoustic communication plays a great role, in particular during the mating period. the study of contact calls emitted by the adults allow enables identification of some acoustic parameters which may be used for individual recognition. it appears that the frequential values of the harmonics, the distribution of energy in the spectrum as well as beats (mimicking amplitude modulations) are susceptible to represent individual mar ...19968673616
post-dive blood lactate concentrations in emperor penguins, aptenodytes order to determine an aerobic diving limit (adl) in emperor penguins (aptenodytes forsteri), post-dive blood lactate concentrations were measured in penguins foraging at an isolated sea ice hole. resting lactate concentrations were 1.2-2.7 mmol l-1. serial samples revealed that lactate level usually peaked within 5 min after dives and that 7-12 min was required for lactate concentrations to decrease from 5-8 mmol l-1 to less than 2.5 mmol l-1. post-dive lactate level was not elevated above 3 ...19979202449
the energy assimilation efficiency of emperor penguins, aptenodytes forsteri, fed a diet of antarctic krill, euphausia superba.captive emperor penguins in antarctica hand-fed antarctic krill assimilated an average of 70.5% +/- 1.7% (n = 3) of the energy in the diet. water intake estimated by tritiated water turnover was 9.4% +/- 2.4% less than that measured gravimetrically. tritium took 1.5 h from injection to equilibrate with the penguins' body water pools.19979231373
structural and biochemical characteristics of locomotory muscles of emperor penguins, aptenodytes forsteri.structural and biochemical characteristics of the primary muscles used for swimming (pectoralis, pec and supracoracoideus, sc) were compared to those of leg muscles in emperor penguins (aptenodytes forsteri). the mass of pec-sc was four times that of the leg musculature, and mitochondrial volume density in pec and sc (4%) was two-thirds that in sartorius (s) and gastrocnemius. the differences in muscle mass and mitochondrial density yielded a 2.2-fold greater total mitochondrial content in pec-s ...19979271809
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 ...19989530242
endocrine correlates of parental care in an antarctic winter breeding seabird, the emperor penguin, aptenodytes forsteri.plasma levels of luteinizing hormone (lh) and prolactin associated with parental behavior were measured in the antarctic winter breeding emperor penguin, aptenodytes forsteri. males exclusively incubate the egg while females exclusively brood the nonhomeothermic young; both sexes alternate in rearing the homeothermic young. birds were sampled on arrival from the sea through egg laying, incubation, and brooding. all parent birds lost their chicks at the end of the brooding period due to harsh wea ...199910049598
development of diving capacity in emperor compare the diving capacities of juvenile and adult emperor penguins aptenodytes forsteri, and to determine the physiological variables underlying the diving ability of juveniles, we monitored diving activity in juvenile penguins fitted with satellite-linked time/depth recorders and examined developmental changes in body mass (mb), hemoglobin concentration, myoglobin (mb) content and muscle citrate synthase and lactate dehydrogenase activities. diving depth, diving duration and time-at-depth ...199910069967
fatty acid composition of the adipose tissue and yolk lipids of a bird with a marine-based diet, the emperor penguin (aptenodytes forsteri).the emperor penguin (aptenodytes forsteri) is an antarctic seabird feeding mainly on fish and therefore has a high dietary intake of n-3 polyunsaturated fatty acids. the yolk is accumulated in the developing oocyte while the females are fasting, and a large proportion of the fatty acid components of the yolk lipids are derived by mobilization from the female's adipose tissue. the fatty acid composition of the total lipid of the yolk was characterized by high levels of n-3 polyunsaturated fatty a ...199910230723
the myoglobin of emperor penguin (aptenodytes forsteri): amino acid sequence and functional adaptation to extreme the framework of a study on molecular adaptations of the oxygen-transport and storage systems to extreme conditions in antarctic marine organisms, we have investigated the structure/function relationship in emperor penguin (aptenodytes forsteri) myoglobin, in search of correlation with the bird life style. in contrast with previous reports, the revised amino acid sequence contains one additional residue and 15 differences. the oxygen-binding parameters seem well adapted to the diving behaviou ...199910327612
penguins use the two-voice system to recognize each other.the sound-producing structure in birds is the syrinx, which is usually a two-part organ located at the junction of the bronchi. as each branch of the syrinx produces sound independently, many birds have two acoustic sources. thirty years ago, we had anatomical, physiological and acoustical evidence of this two-voice phenomenon but no function was known. in songbirds, often these two voices with their respective harmonics are not activated simultaneously but they are obvious in large penguins and ...200010885512
bird communication: two voices are better than 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.200010996089
sub-ice foraging behavior of emperor penguins.emperor penguins (aptenodytes forsteri) were equipped with a remote underwater video camera, the crittercam, to evaluate sub-ice foraging behavior while the birds dived from an isolated dive hole. three birds dived and foraged successfully for 1 h periods after being trained to wear and to dive with a harness for camera attachment. video and depth profile recordings revealed that emperor penguins travel at shallow depths (<50 m), ascend to the undersurface of the ice to feed on fish, and descend ...200011023847
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 ...200111246051
emperor penguins and climate change.variations in ocean-atmosphere coupling over time in the southern ocean have dominant effects on sea-ice extent and ecosystem structure, but the ultimate consequences of such environmental changes for large marine predators cannot be accurately predicted because of the absence of long-term data series on key demographic parameters. here, we use the longest time series available on demographic parameters of an antarctic large predator breeding on fast ice and relying on food resources from the so ...200111346792
energetic cost of foraging in free-diving emperor penguins.hypothesizing that emperor penguins (aptenodytes forsteri) would have higher daily energy expenditures when foraging for their food than when being hand-fed and that the increased expenditure could represent their foraging cost, we measured field metabolic rates (fmr; using doubly labeled water) over 4-d periods when 10 penguins either foraged under sea ice or were not allowed to dive but were fed fish by hand. surprisingly, penguins did not have higher rates of energy expenditure when they dove ...200111436138
temperature regulation in emperor penguins foraging under sea ice.inferior vena caval (ivc) and anterior abdominal (aa) temperatures were recorded in seven emperor penguins (aptenodytes forsteri) foraging under sea ice in order to evaluate the hypothesis that hypothermia-induced metabolic suppression might extend aerobic diving time. diving durations ranged from 1 to 12.5 min, with 39% of dives greater than the measured aerobic dive limit of 5.6 min. anterior abdominal temperature decreased progressively throughout dives, and partially returned to pre-dive val ...200111440867
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 ...200212202819
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 ...200212432000
regional heterothermy and conservation of core temperature in emperor penguins diving under sea ice.temperatures were recorded at several body sites in emperor penguins (aptenodytes forsteri) diving at an isolated dive hole in order to document temperature profiles during diving and to evaluate the role of hypothermia in this well-studied model of penguin diving physiology. grand mean temperatures (+/-s.e.) in central body sites during dives were: stomach: 37.1+/-0.2 degrees c (n=101 dives in five birds), pectoral muscle: 37.8+/-0.1 degrees c (n=71 dives in three birds) and axillary/brachial v ...200312829055
embryology of the emperor penguin (aptenodytes forsteri). 195313036899
[paradoxic sexual cycle of aptenodytes forsteri]. 195313161281
emperor penguins adjust swim speed according to the above-water height of ice holes through which they exit.emperor penguins leap from the water onto the sea ice. their ability to reach above-water height depends critically on initial vertical speed of their leaping, assuming that the kinetic energy is converted to gravitational potential energy. we deliberately changed the above-water heights of ice hole exits, in order to examine whether penguins adjusted swim speed in accordance with the above-water height of the ice. penguins were maintained in a corral on the fast ice in antarctica, and voluntari ...200515961741
evidence of a shift in the cyclicity of antarctic seabird dynamics linked to climate.ecosystems and populations are known to be influenced not only by long-term climatic trends, but also by other short-term climatic modes, such as interannual and decadal-scale variabilities. because interactions between climatic forcing, biotic and abiotic components of ecosystems are subtle and complex, analysis of long-term series of both biological and physical factors is essential to understanding these interactions. here, we apply a wavelet analysis simultaneously to long-term datasets on t ...200516024342
air sac po2 and oxygen depletion during dives of emperor order to determine the rate and magnitude of respiratory o2 depletion during dives of emperor penguins (aptenodytes forsteri), air sac o2 partial pressure (po2) was recorded in 73 dives of four birds at an isolated dive hole. these results were evaluated with respect to hypoxic tolerance, the aerobic dive limit (adl; dive duration beyond which there is post-dive lactate accumulation) and previously measured field metabolic rates (fmrs). 55% of dives were greater in duration than the previousl ...200516043602
taking physiology to the field: using physiological approaches to answer questions about animals in their environments.both technological and conceptual advances continue to enhance our ability to evaluate physiological mechanisms in free-living animals. although complex and uncontrolled natural environments may challenge our ability to define causal mechanistic relationships, they provide opportunities not available in more conventional laboratory settings. among these opportunities are the ability to observe the interplay between physiology and behavior, the potential inspiration to physiological studies from ...201016555183
kidnapping of chicks in emperor penguins: a hormonal by-product?the function and causes of kidnapping juveniles are little understood because individuals sustain some breeding costs to rear an unrelated offspring. here we focus on the proximal causes of this behaviour in emperor penguins (aptenodytes forsteri), whose failed breeders often kidnap chicks. we experimentally tested the hypothesis that kidnapping behaviour was the result of high residual levels of prolactin (prl), a hormone involved in parental behaviour. penguins with artificially decreased prl ...200616574801
huddling behavior in emperor penguins: dynamics of huddling.although huddling was shown to be the key by which emperor penguins (aptenodytes forsteri) save energy and sustain their breeding fast during the antarctic winter, the intricacies of this social behavior have been poorly studied. we recorded abiotic variables with data loggers glued to the feathers of eight individually marked emperor penguins to investigate their thermoregulatory behavior and to estimate their "huddling time budget" throughout the breeding season (pairing and incubation period) ...200616740281
aerobic dive limit. what is it and is it always used appropriately?the original definition of aerobic dive limit (adl) was the dive duration after which there is an increase in post-dive concentration of lactate in the blood of weddell seals freely diving in the field. the only other species in which such measurements have been made is the emperor penguin. for all other species, aerobic dive limit has been calculated (cadl) by dividing usable oxygen stores with an estimation of the rate of oxygen consumption during diving. unfortunately, cadl is often referred ...200616846744
corticosterone in relation to body mass in adelie penguins (pygoscelis adeliae) affected by unusual sea ice conditions at ross island, antarctica.penguins naturally fast each year during breeding and again whilst moulting, and may lose more than 40% of body mass during a fast. fasting in emperor (aptenodytes forsteri) and king (aptenodytes patagonicus) penguins has been divided into three phases, with phase iii characterised by an increased rate of body mass loss, increased plasma corticosterone concentrations, and a change in behaviour leading to abandonment of the breeding attempt and return to sea to feed. initial corticosterone concen ...200616876799
body temperature changes induced by huddling in breeding male emperor penguins.huddling is the key energy-saving mechanism for emperor penguins to endure their 4-mo incubation fast during the antarctic winter, but the underlying physiological mechanisms of this energy saving have remained elusive. the question is whether their deep body (core) temperature may drop in association with energy sparing, taking into account that successful egg incubation requires a temperature of about 36 degrees c and that ambient temperatures of up to 37.5 degrees c may be reached within tigh ...200716959865
ultraviolet reflecting photonic microstructures in the king penguin beak.king and emperor penguins (aptenodytes patagonicus and aptenodytes forsteri) are the only species of marine birds so far known to reflect ultraviolet (uv) light from their beaks. unlike humans, most birds perceive uv light and several species communicate using the near uv spectrum. indeed, uv reflectance in addition to the colour of songbird feathers has been recognized as an important signal when choosing a mate. the king penguin is endowed with several highly coloured ornaments, notably its be ...200517148195
primary structure of myoglobins from 31 species of birds.primary structure of myoglobins (mbs) from 31 avian species of 15 orders were reported, although portions of the structures in the 2 species could not be determined. at least 68 of the total 153 amino acid sites were invariant all through the avian, reptilian and human mbs, and 20 of these sites were "internal", forming the internal hydrophobic cavities in which the heme group remains wrapped. furthermore, at 27 sites, if replaced, the replacements were mostly conservative, and 13 of the conserv ...200817997117
returning on empty: extreme blood o2 depletion underlies dive capacity of emperor penguins.blood gas analyses from emperor penguins (aptenodytes forsteri) at rest, and intravascular p(o(2)) profiles from free-diving birds were obtained in order to examine hypoxemic tolerance and utilization of the blood o(2) store during dives. analysis of blood samples from penguins at rest revealed arterial p(o(2))s and o(2) contents of 68+/-7 mmhg (1 mmhg= 133.3 pa) and 22.5+/-1.3 ml o(2) dl(-1) (n=3) and venous values of 41+/-10 mmhg and 17.4+/-2.9 ml o(2) dl(-1) (n=9). corresponding arterial and ...200718055617
energy saving processes in huddling emperor penguins: from experiments to theory.this paper investigates the energy savings of male emperor penguins aptenodytes forsteri linked to their huddling behaviour, the key factor that allows them to assume their incubating task while undergoing a long fast. drawing on new studies by our team, this review examines the energetic benefits accrued from huddling and estimates the respective contributions of wind protection, exposure to mild ambient temperatures, reduction in cold-exposed body surfaces and body temperature adjustments in t ...200818083725
gas research finds that the emperor penguin is able to tolerate extremely low oxygen levels during its dives for food.200818228637
heart rate regulation and extreme bradycardia in diving emperor investigate the diving heart rate (f(h)) response of the emperor penguin (aptenodytes forsteri), the consummate avian diver, birds diving at an isolated dive hole in mcmurdo sound, antarctica were outfitted with digital electrocardiogram recorders, two-axis accelerometers and time depth recorders (tdrs). in contrast to any other freely diving bird, a true bradycardia (f(h) significantly <f(h) at rest) occurred during diving [dive f(h) (total beats/duration)=57+/-2 beats min(-1), f(h) at rest= ...200818375841
corticosterone responses to capture and restraint in emperor and adelie penguins in antarctica.birds respond to capture, handling and restraint with increased secretion of corticosterone, a glucocorticoid hormone that helps birds adjust to stressful situations. hoods are reported to calm birds, but possible effects of hoods on corticosterone responses have not been reported for any bird. corticosterone responses to restraint in adelie penguins held by their legs with their head covered by a hood were markedly lower than responses of penguins restrained in a mesh bag inside a cardboard box ...200818393566
o2 store management in diving emperor order to further define o(2) store utilization during dives and understand the physiological basis of the aerobic dive limit (adl, dive duration associated with the onset of post-dive blood lactate accumulation), emperor penguins (aptenodytes forsteri) were equipped with either a blood partial pressure of oxygen (p(o(2))) recorder or a blood sampler while they were diving at an isolated dive hole in the sea ice of mcmurdo sound, antarctica. arterial p(o(2)) profiles (57 dives) revealed that ( ...200919112140
demographic models and ipcc climate projections predict the decline of an emperor penguin population.studies have reported important effects of recent climate change on antarctic species, but there has been to our knowledge no attempt to explicitly link those results to forecasted population responses to climate change. antarctic sea ice extent (sie) is projected to shrink as concentrations of atmospheric greenhouse gases (ghgs) increase, and emperor penguins (aptenodytes forsteri) are extremely sensitive to these changes because they use sea ice as a breeding, foraging and molting habitat. we ...200919171908
icy insights from emperor penguins. 200919193852
emperor penguin mates: keeping together in the emperor penguins have no breeding territories, a key issue for both members of a pair is not to be separated until the egg is laid and transferred to the male. both birds remain silent after mating and thereby reduce the risk of having the pair bond broken by unpaired birds. however, silence prevents finding each other if the pair is separated. huddles-the key to saving energy in the cold and the long breeding fast-continuously form and break up, but not all birds are involved simultaneously. ...200919324739
high-affinity hemoglobin and blood oxygen saturation in diving emperor penguins.the emperor penguin (aptenodytes forsteri) thrives in the antarctic underwater environment, diving to depths greater than 500 m and for durations longer than 23 min. to examine mechanisms underlying the exceptional diving ability of this species and further describe blood oxygen (o2) transport and depletion while diving, we characterized the o2-hemoglobin (hb) dissociation curve of the emperor penguin in whole blood. this allowed us to (1) investigate the biochemical adaptation of hb in this spe ...200919801437
hypoxemic and ischemic tolerance in emperor penguins.oxygen store depletion and a diving bradycardia in emperor penguins (aptenodytes forsteri) expose tissues to critical levels of hypoxemia and ischemia. to assess the prevention of re-perfusion injury and reactive oxygen species (ros) damage in emperor penguins, superoxide radical production, lipid peroxidation (thiobarbituric acid reactive substances (tbars)), and antioxidant enzyme activity profiles in biopsy samples from muscle and liver were determined and compared to those in the chicken and ...201020172048
mating behavior, population growth, and the operational sex ratio: a periodic two-sex model approach.we present a new approach to modeling two-sex populations, using periodic, nonlinear two-sex matrix models. the models project the population growth rate, the population structure, and any ratio of interest (e.g., operational sex ratio). the periodic formulation permits inclusion of highly seasonal behavioral events. a periodic product of the seasonal matrices describes annual population dynamics. the model is nonlinear because mating probability depends on the structure of the population. to st ...201020408757
myoglobin production in emperor penguins.increased oxygen storage is essential to the diving capacities of marine mammals and seabirds. however, the molecular mechanisms underlying this adaptation are unknown. myoglobin (mb) and mb mrna concentrations were analyzed in emperor penguin (aptenodytes forsteri) adults and chicks with spectrophotometric and rnase protection assays to evaluate production of their large mb-bound o(2) stores. mean pectoral mb concentration and mb mrna content increased throughout the pre-fledging period and wer ...201020472777
first recorded loss of an emperor penguin colony in the recent period of antarctic regional warming: implications for other 1948, a small colony of emperor penguins aptenodytes forsteri was discovered breeding on emperor island (67-¦ 51' 52ôç¦ s, 68-¦ 42' 20ôç¦ w), in the dion islands, close to the west antarctic peninsula (stonehouse 1952). when discovered, the colony comprised approximately 150 breeding pairs; these numbers were maintained until 1970, after which time the colony showed a continuous decline. by 1999 there were fewer than 20 pairs, and in 2009 high-resolution aerial photography revealed no remaini ...201121386883
what triggers the aerobic dive limit? patterns of muscle oxygen depletion during dives of emperor penguins.the physiological basis of the aerobic dive limit (adl), the dive duration associated with the onset of post-dive blood lactate elevation, is hypothesized to be depletion of the muscle oxygen (o(2)) store. a dual wavelength near-infrared spectrophotometer was developed and used to measure myoglobin (mb) o(2) saturation levels in the locomotory muscle during dives of emperor penguins (aptenodytes forsteri). two distinct patterns of muscle o(2) depletion were observed. type a dives had a monotonic ...201121562166
coordinated movements prevent jamming in an emperor penguin huddle.for emperor penguins (aptenodytes forsteri), huddling is the key to survival during the antarctic winter. penguins in a huddle are packed so tightly that individual movements become impossible, reminiscent of a jamming transition in compacted colloids. it is crucial, however, that the huddle structure is continuously reorganized to give each penguin a chance to spend sufficient time inside the huddle, compared with time spent on the periphery. here we show that emperor penguins move collectively ...201121673816
chlorinated biphenyls and pesticides in migrating and resident seabirds from east and west antarctica.the unhatched eggs of the following seabirds were analyzed to quantify pcbs, hexachlorobenzene (hcb), +¦-, +¦-, +¦-, +¦-hexachlorocyclohexanes (hchs), o,p' and p,p' isomers of ddt, ddd and dde: resident ad+¿lie (pygoscelis ad+¿liae, adpe) and emperor (aptenodytes forsteri, empe) penguins, migrating snow petrel (pagodroma nivea, snpt) and south polar skua (catharacta maccormicki, spsk) from the ross sea (east antarctica); and migrating brown skua (catharacta antartica, brsk) and resident adpe fro ...201121704375
stroke rates and diving air volumes of emperor penguins: implications for dive performance.emperor penguins (aptenodytes forsteri), both at sea and at an experimental dive hole, often have minimal surface periods even after performance of dives far beyond their measured 5.6 min aerobic dive limit (adl: dive duration associated with the onset of post-dive blood lactate accumulation). accelerometer-based data loggers were attached to emperor penguins diving in these two different situations to further evaluate the capacity of these birds to perform such dives without any apparent prolon ...201121832128
In pursuit of Irving and Scholander: a review of oxygen store management in seals and penguins.Since the introduction of the aerobic dive limit (ADL) 30 years ago, the concept that most dives of marine mammals and sea birds are aerobic in nature has dominated the interpretation of their diving behavior and foraging ecology. Although there have been many measurements of body oxygen stores, there have been few investigations of the actual depletion of those stores during dives. Yet, it is the pattern, rate and magnitude of depletion of O(2) stores that underlie the ADL. Therefore, in order ...201121957096
point of no return in diving emperor penguins: is the timing of the decision to return limited by the number of strokes?at some point in a dive, breath-hold divers must decide to return to the surface to breathe. the issue of when to end a dive has been discussed intensively in terms of foraging ecology and behavioral physiology, using dive duration as a temporal parameter. inevitably, however, a time lag exists between the decision of animals to start returning to the surface and the end of the dive, especially in deep dives. in the present study, we examined the decision time in emperor penguins under two diffe ...201222162861
biological plasticity in penguin heat-retention structures.insulation and vascular heat-retention mechanisms allow penguins to forage for a prolonged time in water that is much cooler than core body temperature. wing-based heat retention involves a plexus of humeral arteries and veins, which redirect heat to the body core rather than to the wing periphery. the humeral arterial plexus is described here for eudyptes and megadyptes, the only extant penguin genera for which wing vascular anatomy had not previously been reported. the erect-crested (eudyptes ...201222213564
muscle energy stores and stroke rates of emperor penguins: implications for muscle metabolism and dive diving birds and mammals, bradycardia and peripheral vasoconstriction potentially isolate muscle from the circulation. during complete ischemia, atp production is dependent on the size of the myoglobin oxygen (o(2)) store and the concentrations of phosphocreatine (pcr) and glycogen (gly). therefore, we measured pcr and gly concentrations in the primary underwater locomotory muscle of emperor penguin and modeled the depletion of muscle o(2) and those energy stores under conditions of complete ...201722418705
an emperor penguin population estimate: the first global, synoptic survey of a species from space.our aim was to estimate the population of emperor penguins (aptenodytes fosteri) using a single synoptic survey. we examined the whole continental coastline of antarctica using a combination of medium resolution and very high resolution (vhr) satellite imagery to identify emperor penguin colony locations. where colonies were identified, vhr imagery was obtained in the 2009 breeding season. the remotely-sensed images were then analysed using a supervised classification method to separate penguins ...201222514609
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 ...201223015628
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 ...201223185608
emperor penguin body surfaces cool below air temperature.emperor penguins aptenodytes forsteri are able to survive the harsh antarctic climate because of specialized anatomical, physiological and behavioural adaptations for minimizing heat loss. heat transfer theory predicts that metabolic heat loss in this species will mostly depend on radiative and convective cooling. to examine this, thermal imaging of emperor penguins was undertaken at the breeding colony of pointe géologie in terre adélie (66°40' s 140° 01' e), antarctica in june 2008. during cle ...201323466479
the oceanography and ecology of the ross sea.the continental shelf of the ross sea exhibits substantial variations in physical forcing, ice cover, and biological processes on a variety of time and space scales. its circulation is characterized by advective inputs from the east and exchanges with off-shelf regions via the troughs along the northern portions. phytoplankton biomass is greater there than anywhere else in the antarctic, although nitrate is rarely reduced to levels below 10 ╬╝mol l(-1). overall growth is regulated by irradiance ( ...201423987914
transport of nutrients and contaminants from ocean to island by emperor penguins from amanda bay, east antarctic.penguins play important roles in the biogeochemical cycle between antarctic ocean and land ecosystems. the roles of emperor penguin aptenodytes forsteri, however, are usually ignored because emperor penguin breeds in fast sea ice. in this study, we collected two sediment profiles (epi and pi) from the n island near a large emperor penguin colony at amanda bay, east antarctic and performed stable isotope and element analyses. the organic c/n ratios and carbon and nitrogen isotopes suggested an au ...201424056448
emperor penguins breeding on iceshelves.we describe a new breeding behaviour discovered in emperor penguins; utilizing satellite and aerial-survey observations four emperor penguin breeding colonies have been recorded as existing on ice-shelves. emperors have previously been considered as a sea-ice obligate species, with 44 of the 46 colonies located on sea-ice (the other two small colonies are on land). of the colonies found on ice-shelves, two are newly discovered, and these have been recorded on shelves every season that they have ...201424416381
effects of climate change on an emperor penguin population: analysis of coupled demographic and climate models.sea ice conditions in the antarctic affect the life cycle of the emperor penguin (aptenodytes forsteri). we present a population projection for the emperor penguin population of terre adélie, antarctica, by linking demographic models (stage-structured, seasonal, nonlinear, two-sex matrix population models) to sea ice forecasts from an ensemble of ipcc climate models. based on maximum likelihood capture-mark-recapture analysis, we find that seasonal sea ice concentration anomalies (sica ) affect ...201224501054
deep-diving sea lions exhibit extreme bradycardia in long-duration dives.heart rate and peripheral blood flow distribution are the primary determinants of the rate and pattern of oxygen store utilisation and ultimately breath-hold duration in marine endotherms. despite this, little is known about how otariids (sea lions and fur seals) regulate heart rate (fh) while diving. we investigated dive fh in five adult female california sea lions (zalophus californianus) during foraging trips by instrumenting them with digital electrocardiogram (ecg) loggers and time depth re ...201424790100
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 ...201424963661
gastrointestinal parasite fauna of emperor penguins (aptenodytes forsteri) at the atka bay, general, the knowledge on parasites infecting antarctic birds is scarce. the present study intends to extend the knowledge on gastrointestinal parasites of emperor penguins (aptenodytes forsteri) at the atka bay, antarctica. fecal samples of 50 individual emperor penguins were collected at the atka bay and analyzed using the sodium-acetate-formaldehyde (saf) method for the identification of intestinal helminth eggs and/or protozoan parasite stages. in addition, coproantigen elisas were perfor ...201425164274
marine mammals and emperor penguins: a few applications of the krogh principle.the diving physiology of aquatic animals at sea began 50 years ago with studies of the weddell seal. even today with the advancements in marine recording and tracking technology, only a few species are suitable for investigation. the first experiments were in mcmurdo sound, antarctica. in this paper are examples of what was learned in antarctica and elsewhere. some methods employed relied on willingness of weddell seals and emperor penguins to dive under sea ice. diving depth and duration were o ...201525411360
comparative genomic data of the avian phylogenomics project.the evolutionary relationships of modern birds are among the most challenging to understand in systematic biology and have been debated for centuries. to address this challenge, we assembled or collected the genomes of 48 avian species spanning most orders of birds, including all neognathae and two of the five palaeognathae orders, and used the genomes to construct a genome-scale avian phylogenetic tree and perform comparative genomics analyses (jarvis et al. in press; zhang et al. in press). he ...201425671091
two antarctic penguin genomes reveal insights into their evolutionary history and molecular changes related to the antarctic environment.penguins are flightless aquatic birds widely distributed in the southern hemisphere. the distinctive morphological and physiological features of penguins allow them to live an aquatic life, and some of them have successfully adapted to the hostile environments in antarctica. to study the phylogenetic and population history of penguins and the molecular basis of their adaptations to antarctica, we sequenced the genomes of the two antarctic dwelling penguin species, the adélie penguin [pygoscelis ...201425671092
too much of a good thing: sea ice extent may have forced emperor penguins into refugia during the last glacial maximum.the relationship between population structure and demographic history is critical to understanding microevolution and for predicting the resilience of species to environmental change. using mitochondrial dna from extant colonies and radiocarbon-dated subfossils, we present the first microevolutionary analysis of emperor penguins (aptenodytes forsteri) and show their population trends throughout the last glacial maximum (lgm, 19.5-16 kya) and during the subsequent period of warming and sea ice re ...201525728986
penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy.the anatomy and volume of the penguin respiratory system contribute significantly to pulmonary baroprotection, the body o2 store, buoyancy and hence the overall diving physiology of penguins. therefore, three-dimensional reconstructions from computerized tomographic (ct) scans of live penguins were utilized to measure lung volumes, air sac volumes, tracheobronchial volumes and total body volumes at different inflation pressures in three species with different dive capacities [adélie (pygoscelis ...201525740902
the influence of historical climate changes on southern ocean marine predator populations: a comparative analysis.the southern ocean ecosystem is undergoing rapid physical and biological changes that are likely to have profound implications for higher-order predators. here, we compare the long-term, historical responses of southern ocean predators to climate change. we examine palaeoecological evidence for changes in the abundance and distribution of seabirds and marine mammals, and place these into context with palaeoclimate records in order to identify key environmental drivers associated with population ...201626391440
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