Vision does not impact walking performance in Argentine ants

The bumpy road ahead: the role of substrate roughness on animal walking and a proposed comparative metric

Outside laboratory conditions and human-made structures, animals rarely encounter flat surfaces. Instead, natural substrates are uneven surfaces with height variation that ranges from the microscopic scale to the macroscopic scale. For walking animals (which we define as encompassing any form of legged movement across the ground, such as walking, running, galloping, etc.), such substrate 'roughness' influences locomotion in a multitude of ways across scales, from roughness that influences how each toe or foot contacts the ground, to larger obstacles that animals must move over or navigate around. Historically, the unpredictability and variability of natural environments has limited the ability to collect data on animal walking biomechanics. However, recent technical advances, such as more sensitive and portable cameras, biologgers, laboratory tools to fabricate rough terrain, as well as the ability to efficiently store and analyze large variable datasets, have expanded the opportunity to study how animals move under naturalistic conditions. As more researchers endeavor to assess walking over rough terrain, we lack a consistent approach to quantifying roughness and contextualizing these findings. This Review summarizes existing literature that examines non-human animals walking on rough terrain and presents a metric for characterizing the relative substrate roughness compared with animal size. This framework can be applied across terrain and body scales, facilitating direct comparisons of walking over rough surfaces in animals ranging in size from ants to elephants.

The perceived effects of augmented trail sensing and mood recognition abilities in a human-fish biohybrid system

The use of technologies to enhance human and animal perception has been explored in pioneering research about artificial life and biohybrid systems. These attempts have revealed that augmented sensing abilities can emerge from new interactions between individuals within or across species. Nevertheless, the diverse effects of different augmented capabilities have been less examined and compared. In this work, we built a human-fish biohybrid system that enhanced the vision of the ornamental fish by projecting human participants onto the arena background. In contrast, human participants were equipped with a mixed-reality device, which visualized individual fish trails (representing situation-oriented perceptions) and emotions (representing communication-oriented perceptions). We investigated the impacts of the two enhanced perceptions on the human side and documented the perceived effects from three aspects. First, both augmented perceptions considerably increase participants' attention toward ornamental fish, and the impact of emotion recognition is more potent than trail sense. Secondly, the frequency of human-fish interactions increases with the equipped perceptions. The mood recognition ability on the human side can indirectly promote the recorded positive mood of fish. Thirdly, most participants mentioned that they felt closer to those fish which had mood recognition ability, even if we added some mistakes in the accuracy of mood recognition. In contrast, the addition of trail sensing ability does not lead to a similar effect on the mental bond. These findings reveal several aspects of different perceived effects between the enhancements of communication-oriented and situation-oriented perceptions.