Table 1.

Summary of data for heart migration in terrestrial and aquatic species of snakes.

Species	Slopea	Heart Migration cm HH/10 cm TL	Relative Heart Position, % TL Mean ± SE	range TL cm	G Maxb mm HG	Ontogenetic Heart Migrationc	G Ontogenyd mm HG	G Max Ontogenye mm Hg	Mean Arterial Pressuref mm Hg
Aquatic
Acrochordus granulatus	0.45	4.48	45.1 ± 1.47	20.7–76.2 (55.5)	26.57	0.34	0.26	0.60	27
Hydrophis platurus	0.23	2.26	24.75 ± 1.16	26.2–76.5 (50.3)	14.64	2.19	1.69	4.32
Terrestrial
Agkistrodon piscivorus	0.31	3.05	33.32 ± 0.11	31.5–155.3 (123.8)	39.62	6.52	5.04	5.23	32
Arboreal
Pantherophis obsoleta	0.15	1.54	17.48 ± 0.14	53.5–182 (128.5)	24.59	5.89	4.55	4.55	62

^aSlopes of data plots based on overall simple linear regression of HH on TL.

^bGravitational pressure head of blood above heart in fully vertical, head-up position, for longest adult snake in sample.

^cHeadward migration of heart, in cm, from smallest snake in sample to largest snake in sample.

^dGravitational pressure head of vertical blood column represented by migration of the heart during ontogeny

^eGravitational pressure head of vertical blood column represented by migration of the heart during ontogeny, standardized to maximum ontogenetic increase of TL equivalent to that of Pantherophis obsoleta (128.5 cm).

^fMean resting arterial pressure in horizontal position (Lillywhite, 1987)