... but also need to resist excessive stresses caused by accidental collisions. This Commentary provides a summary of the literature on damage-reducing morphological adaptations in wings, covering natural causes of wing collisions, their impact on the structural integrity of wings and associated consequences...

... velocity is small, so the energy absorbing collisions are small. In a simple model, cutting the step length in half cuts the collisional energy loss per step by four, and the energy loss per unit distance in half ( Kuo, 2002 ). If steps were small enough, the CoM would travel nearly in parallel...

... moving. The instantaneous COM collision angle (φ) can be calculated as ( Lee et al., 2011 ): To determine how the COM collisional angles change across gait and speed, we examined the change in λ, θ and φ with forward velocity. For comparative purposes, the weighted average of each...

... to walking down a gentle slope in order to overcome collisional losses. The relevance of the energetic cost of collisions at each limb placement is being increasingly understood in a variety of locomotory systems, including bipedal walking ( Kuo, 2002 ; Donelan et al., 2002 ; Collins et al., 2005 ), gibbon...

... that would allow a smooth transition into the swing phase. The sudden change in velocity due to such an overshoot is associated with a collision. Assuming neither the handhold nor the gibbon stores elastic strain energy, the energetic consequences of such overshoots can be calculated. We suggest two reasons...