Acrobatic squirrels learn to leap and land on tree branches without falling

Arboreal animals often leap through complex canopies to travel and avoid predators. Their success at making split-second potentially life-threatening decisions of biomechanical capability depends on skillful use of acrobatic maneuvers and learning from past efforts. Here, we found that free-ranging fox squirrels (Sciurus niger) leaping across novel, simulated branches decided where to launch by balancing a trade-off between gap distance and branch-bending compliance. Squirrels quickly learned to modify impulse generation upon repeated leaps from novel, compliant beams. A repertoire of agile landing maneuvers enabled targeted leaping without falling. Unanticipated adaptive landing and leaping “parkour” behavior revealed an innovative solution for, particularly challenging leaps. Squirrels deciding and learning how to launch and land demonstrate the synergistic roles of biomechanics and cognition in robust gap crossing strategies.树栖动物常穿梭于复杂的林冠层间跳跃移动，以此躲避天敌。它们能否在瞬息之间做出关乎生死的生物力学决策，取决于对杂技式机动动作的娴熟运用以及过往经验的学习。在此研究中，我们发现野生狐松鼠（Sciurus niger）在跨越新型模拟树枝时，会通过权衡间隙距离与树枝弯曲柔顺性来决定起跳位置。松鼠在反复从新型柔顺横梁上跳跃后，能够快速调整冲量的产生。一系列灵活的着陆动作使其能够精准跳跃而不跌落。未被预料到的适应性着陆与跳跃"跑酷（parkour）"行为，为极具挑战性的跳跃任务提供了创新性解决方案。松鼠在决策并学习起跳与着陆方式的过程中，展现了生物力学与认知在稳健的跨间隙策略中的协同作用。