Three Macropus rufus (Macropus meaning big foot) A buck, older male roo, a joey, young roo, and a doe, female. They truly have the optimum “survival of species” reproduction genetics, especially in the doe. The red roo has a body system that keeps them at a constant temperature as well. Extremely clever nature.
Their hopping is more effective than an animal that runs on all four legs and while they hop their diaphragm moves up and down. This empties and fills the lungs automatically. Told you they were clever and made from survival especially in the outback.