Fig. 3. Proton leak curves at 20°C in red muscle and liver mitochondria of the shortfin mako shark (A), blue shark (B) and leopard shark (C). Each data point represents the mean (± s.e.m.) of all individuals sampled for that species. The red muscle curve is higher than the liver curve in all three shark species, but only in the blue shark were the proton leak rates at 160 mV significantly different (paired t-test; P=0.86 for mako shark, 0.02 for blue shark and 0.07 for leopard shark).