Why is a frog's kidneys so big?

A frog's kidneys are relatively large compared to its body size because they play a crucial role in regulating water and electrolyte balance, especially in varying aquatic and terrestrial environments. Frogs have a unique physiology that allows them to conserve water, making their kidneys vital for excretion and osmoregulation. Additionally, the large size aids in filtering waste products efficiently due to their high metabolic rates. This adaptation is essential for surviving in diverse habitats.