Blood pressures and heart rate during larval development in the anuran amphibian Xenopus laevis

The amphibian Xenopus laevis exhibits a variation in its heart rate and blood pressure during the stages of its growth from the initial larval stage to the beginning of metamorphosis. Blood pressure was observed to increase as the amphibian gained in body mass, but the non-linear relationship between pressure and body mass pointed to other factors that may also account for the variation. Meanwhile, heart rate was seen to decline as the amphibian developed.