...Katsufumi Sato; Kozue Shiomi; Greg Marshall; Gerald L. Kooyman; Paul J. Ponganis SUMMARY 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...

...-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 decline, and, in dives near the ADL...

... 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 were 15-fold and 3-fold greater...

... 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 (a) pre-dive P...

...Jessica U. Meir; Torre K. Stockard; Cassondra L. Williams; Katherine V. Ponganis; Paul J. Ponganis SUMMARY To 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...

...Caroline Gilbert; Stéphane Blanc; Yvon Le Maho; André Ancel SUMMARY 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...

...P. J. Ponganis; T. K. Stockard; J. U. Meir; C. L. Williams; K. V. Ponganis; R. P. van Dam; R. Howard SUMMARY 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...

... 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...

...T. Knower Stockard; J. Heil; J. U. Meir; K. Sato; K. V. Ponganis; P. J. Ponganis SUMMARY In order to determine the rate and magnitude of respiratory O 2 depletion during dives of emperor penguins ( Aptenodytes forsteri ),air sac O 2 partial pressure ( P O 2 )was recorded in 73 dives of four birds...

... 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, longitudinal...

...P. J. Ponganis; R. P. Van Dam; G. Marshall; T. Knower; D. H. Levenson ABSTRACT 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...

...P. J. Ponganis; L. N. Starke; M. Horning; G. L. Kooyman ABSTRACT To 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...

...P. J. Ponganis; G. L. Kooyman; L. N. Starke; C. A. Kooyman; T. G. Kooyman ABSTRACT In 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...

...Gerald L. Kooyman; Paul J. Ponganis; Michael A. Castellini; Edward P. Ponganis; Katherine V. Ponganis; Philip H. Thorson; Scott A. Eckert; Yvon Lemaho ABSTRACT Heart rate during overnight rest and while diving were recorded from five emperor penguins with a microprocessor-controlled submersible...