Pygoscelid penguins in a swim canal

Abstract

In Antarctica, we investigated the energy consumption of Adelie (Pygoscelis adeliae), Gentoo (P. papua) and Chinstrap (P. antarctica) penguins while resting in the water (8.4 W-kg−1) and swimming underwater at various speeds, using a 21m long canal filled with sea-water at 4°C in conjunction with respirometry. The birds swam at will and consumed 15.7, 16.1 and 10 W·kg−1 at the speed where cost of transport was minimal (2.1, 2.3 and 2.5 m·s−1 in Adelie, Gentoo and Chinstrap penguins, respectively). Thermal conductance in pygoscelid penguins was 3.3 W·°C−1. m−2 and energy expenditure (Pi, W·kg−1) while resting in the water is given by Pj = -0.3 ta+9.6, where ta is water temperature in °C. During the breeding season, pygoscelid penguins spend 25–40% of their daily energy expenditure while foraging at sea. The importance of accurate estimates of at-sea activity and energy consumption is discussed.