Number of nephrons in a Kangaroo Rat VS Domestic Rat?

Nephrons are a subunit of the kidney. The kidneys are involved in filtration and regulation of solute concentration of urine and blood. Because the kangaroo rat lives in a serer environment, it has to have a more efficient use of the water it takes in, and therefore it will have more developed filtration systems and therefore more nephrons. I could go into a lot more detail, but I won't.