Temperature Regulation of Young Jackass Penguins, Spheniscus Demersus

Abstract

Data from five jackass penguin chicks (mean mass 201 g) showed that even young chicks can increase their oxygen consumption from 0,76± 0,16 ml O₂/gxhr at 35°C to 2,09± 0,21 ml O₂ at 20 ^oC. Close parental attendance may therefore be interpreted not only as protection against aerial predators but also as creating a microclimate which could favour a decrease in maintenance requirements and thus channel a substantial part of the available energy into growth. A decrease in rectal temperature, despite the increase in heat production, is interpreted as indicative of poor insulative properties ot the down. Preliminary data on the ontogeny of thermoregulation indicate that penguin chicks may attain mature thermoregulatory abilities at a mass of approximately 400g.