The video explores the discovery of small holes in the snow leading to tunnels, revealing the subnivean zone, a space under the snow that serves as a warm shelter for small animals like voles. This zone is formed by snow accumulating on plants and rocks, creating air pockets. It provides safety from predators, as most are too large to enter. The subnivean zone is a hidden world of tunnels and rooms, offering a unique ecosystem for survival during winter.

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