Record Details

Vleck, David;Gleeson, Todd T;Bartholomew, George A
Oxygen consumption during swimming in Galapagos marine iguanas and its ecological correlates
Journal of Comparative Physiology B
Journal Article
Amblyrhynchus cristatus
Oxygen consumption, undulation frequency, and tether force as an index to power output were measured in tethered, swimming marine iguanas. Power output increased linearly with total oxygen consumption and mass-specific oxygen consumption increased linearly with undulation frequency (Figs. 1 and 2). Velocity of free swimming iguanas is a linear function of undulation frequency and of total length (Fig. 3), which allows calculation of the equivalent velocity for tethered iguanas undulating in place on a tether. Cost of transport for swimming iguanas decreases as body mass increases, and can be predicted from the equation ml O2/kg·m=0.31M-0.56, where M is mass in kg (Fig. 4). The change in cost of transport with body mass correlates with foraging patterns of different size classes of marine iguanas. Small marine iguanas feed on algae on or near shore while adults obtain algae by swimming offshore and diving. Cost of transport during swimming in marine iguanas is higher than for fish and turtles but lower than for ducks or humans (Fig. 5).