How can mice fall the equivalent of a ten story building to humans and just walk away?
The reason mice and other small animals can survive falls from very great heights is because they have a large surface area relative to their weight [1]. This means that in falling they generate more air resistance, and peak at a much slower speed, acting as a built-in parachute [2]. Their body weight is also reduced by a factor of ten when compared to a horse, meaning that their surface area is also reduced by the same ratio, increasing their resistance to falling [3, 5]. Furthermore, from Haldane's essay "On Being the Right Size," he claimed that the difference could be explained by air resistance and the force of gravity [4]. The force of air resistance scales as $f_r \propto L^2$, where $L$ is a characteristic linear dimension of the animal, while the force due to gravity scales as $f_g\propto L^3$ (assuming fixed density) [4]. The ratio of these quantities scales as $$\frac{f_r}{f_g} \propto L^{-1}$$, meaning that smaller animals are buoyed up more effectively by air resistance as they fall [4].
While mice are small creatures, they have several traits that keep them from getting seriously injured when they fall from high places [1, 3]. First, their small size means that their terminal velocity — the speed at which they fall — is relatively low [1]. Second, their bones are soft and flexible, which aids in absorbing the impact of the fall and keeping them from getting seriously injured [3]. Finally, their tails help them balance their bodies during a fall, allowing them to fall on their legs instead of their head [3]. All of these factors mean that a mouse can survive a fall from a high building, though they will likely sustain some injuries [2]. It is worth noting, however, that some of these traits will not save them from injury or death if they fall from a very high elevation, such as an airplane in flight [4]. In fact, their small size and light bones make them more susceptible to fatal injuries from high falls [2].