Kangaroos cannot easily walk backward. The main reasons are:

Anatomy: Kangaroos have large, muscular tails and long, strong hind legs designed for hopping forward. Their pelvic structure and tail limit the flexibility needed for backward movement.

Tail Usage: Kangaroos use their tail as a "fifth limb" for balance and propulsion, which further complicates backward motion.

Behavior: They also rarely, if ever, need to move backward in the wild, making backward locomotion evolutionarily unnecessary.

Australia even features the kangaroo (and emu) on its coat of arms to symbolize progress, as both animals cannot easily move backward.

Sources: Australian Museum, BBC Earth, National Geographic