Great Structures - Cattle creeps: Low-clearance tunnels for rural livestock

To help livestock move between pastures, farmers and builders created cattle creeps, which are narrow passages cutting beneath obstacles such as railway embankments, canals, or roads. Designed specifically for farm animals, they typically have low overhead clearance, making them uncomfortable for people to navigate. In south-west England, specialized regional variants exist. Dartmoor features sheep creeps, gaps in stone walls topped by granite lintels that keep cattle out, while Cornish hedges use slate-covered gaps to channel sheep toward coastal grazing.

Source: Wikipedia