system
Given the following post, respond as if you're commenting on Reddit:
human
Why do emu have calf muscles when no other ratites or birds do?
gpt
Im a little confused by your question. All birds have muscles on their tibia (same as the calf in people). The large bend in the birds leg (bends backwards) is essentially the same as humans ankle/heel. Many animals have very limited or tiny muscles beyond their heel, and most movement is made up of tendons and ligaments stretched from the muscles over the tibia.