Table 1.

Scaling slopes (b±95% confidence limits) and antilog intercepts (a) of log metabolic rate (ml O₂ h⁻¹) versus log wet body mass (g) of birds and mammals in various physiological states. (The b values (p<0.05 in all cases) were determined by conventional LSR analysis with each species regarded as an independent data point, except where indicated (PIC, phylogenetically independent contrasts; RMA, reduced major axis analysis; MA, major axis analysis; RRA, robust regression analysis; BBM, binned body mass classes). N is the sample size, which is the number of species, or number of estimates with number of species in parentheses. The b values in italics are those used in figure 1.)

physiological state	taxon	b	a	N	source
low metabolic level
hibernation (5°C)	mammals	0.941±0.086	0.047	29	Geiser (1988)
hibernation (20°C)	mammals	0.794±0.064	0.373	36	Geiser (1988)
hibernation (4.3–10.1°C)	mammals	0.879±0.082	0.044	27 (16)	Weiner (1989)
torpor (15–16°C)	birds	1.028±0.210	0.155	8	Lasiewski (1963), Lasiewski & Lasiewski (1967) and Lasiewski et al. (1967)
resting metabolic level	mammals	0.676±0.013	4.98	456	White et al. (2006)
	mammals (RMA)	0.69±0.013	5.10	456	White et al. (2006)
	mammals (BBM)	0.737±0.026	3.25	52 (626)	Savage et al. (2004)
	mammals	0.690	4.11	487	Lovegrove (2000)
	mammals (RRA)	0.678±0.014		391	Heusner (1991)
	mammals	0.693±0.022	4.36	293	Hayssen & Lacy (1985)
	birds	0.64±0.03	6.07	83	White et al. (2006)
	birds (RMA)	0.66±0.03	5.36	83	White et al. (2006)
	birds	0.669±0.030	6.17	126	McKechnie & Wolf (2004)
	birds (PIC)	0.677	4.67	126	McKechnie & Wolf (2004)
	birds	0.635±0.043	8.51	37	Rezende et al. (2002)
	birds (PIC)	0.721±0.087	5.70	37	Rezende et al. (2002)
	birds	0.68±0.06	8.92	45	Frappell et al. (2001)
	birds (PIC)	0.68±0.10	8.43	44	Frappell et al. (2001)
	birds	0.638±0.028	7.75	82	Tieleman & Williams (2000)
	birds (PIC)	0.677±0.054	5.38	82	Tieleman & Williams (2000)
	birds	0.677	6.98	263	Daan et al. (1991)
	birds (MA)	0.67±0.03	4.86	399	Bennett & Harvey (1987)
field metabolic level	mammals	0.734±0.038	9.94	79	Nagy et al. (1999)
	mammals (RMA)	0.75±0.04	4.53	79	White & Seymour (2005)
	mammals (BBM)	0.749±0.054	9.31	35 (79)	Savage et al. (2004)
	mammals	0.72	1.40	111 (86)	Anderson & Jetz (2005)
	mammals (PIC)	0.73	1.40	110 (86)	Anderson & Jetz (2005)
	birds	0.681±0.036	21.66	95	Nagy et al. (1999)
	birds	0.68	2.10	132 (96)	Anderson & Jetz (2005)
	birds (PIC)	0.67	2.10	131 (96)	Anderson & Jetz (2005)
	birds	0.703±0.042	19.84	81	Tieleman & Williams (2000)
	birds (PIC)	0.671±0.065	16.65	81	Tieleman & Williams (2000)
high metabolic level cold-exposed	mammals	0.65±0.05	31.56	70	White & Seymour (2005)
	mammals (RMA)	0.68±0.05	28.3	70	White & Seymour (2005)
	mammals	0.668±0.060	30.34	56 (28)	Weiner (1989)
	birds	0.600±0.033	56.10	47	Rezende et al. (2002)
	birds (PIC)	0.651±0.088	44.36	47	Rezende et al. (2002)
high metabolic level strenuous activity	mammals	0.872±0.059	17.17	34	Weibel et al. (2004)
	mammals (BBM)	0.828±0.070	26.06	21 (28)	Savage et al. (2004)
	athletic
	mammals	0.942±0.050	17.11	10	Weibel et al. (2004)
	mammals	0.857±0.040	18.00	67 (45)	Weiner (1989)
	mammals	0.841±0.045	22.93	18	Koteja (1987)
	birds & mammals	0.879±0.020	35.02	15	Bishop (1999)
	birds	0.837±0.107	33.65	39 (35)	Norberg (1996)