Why do some rodents have long hind legs and long tails?

Some rodents, such as kangaroo rats, jumping mice, gerbils, and jerboas, possess long, powerful hind limbs and long tails as an adaptation for saltatory (leaping) locomotion.12

This mode of movement, often called ricochetal, is typically found in mammals living in open habitats. The specialized body form serves specific functional purposes:2

• Hind Limbs: The elongated, powerful hind legs and feet provide the necessary force for jumping and leaping, which allows these animals to move efficiently across open terrain.12
• Tails: The long tail acts as a critical balancing device, providing stability during these leaps.12

This physical configuration is a result of convergent evolution, where unrelated groups of mammals—including some marsupials and lagomorphs—have independently evolved similar traits to thrive in similar ecological niches.2