Meeting Abstract
Cane toads, Bufo marinus , are exceptional at landing. Using their forelimbs to decelerate the body after impact, they are capable of modulating both the timing and intensity of pre-landing muscle recruitment in relation to hop length. Muscles are typically activated later in longer hops, and pre-landing recruitment intensity in forelimb muscles is also usually higher. To modulate muscle activity patterns, toads likely use sensory feedback to make predictions about the timing and magnitude of impact. To begin to understand the importance of visual feedback on landing preparation, we investigated the ability of cane toads to modulate pre-landing muscle activity appropriately after vision was removed. Specifically, we first recorded landing forces and muscle activity patterns in the coracoradialis and anconeus muscles from seven cane toads as they hopped a variety of distances with vision intact. The optic nerves were then severed and the recordings were repeated. We found that muscle activity patterns were not affected by the optic nerve treatment. Although variability was present across animals, toads typically exhibited later muscle onsets and greater pre-landing recruitment intensity in longer hops, regardless of visual input. Similarly, force profiles from landing toads before and after treatments did not differ greatly. Our results indicate that cane toads, like mammals, are not exclusively reliant on vision to coordinate landing after a jump. Instead, animals can use other sensory modalities, like proprioceptive feedback from the hindlimbs and/or vestibular information collected during takeoff as critical cues to ensure safe, controlled landings.
