Super Seal Sense: Whisker movement strategies in Pinnipeds

主动触摸理论指出，传感器必须移动并参与特定任务的行为，以提高感官任务的效率和性能。人类的指尖是一个主动的触摸系统，因为它们可以进行有目的的特定任务的运动，例如它们扫过纹理，感觉边缘以判断形状，挤压物体以判断硬度。大多数哺乳动物没有移动的触觉指尖，它们有触须触摸传感器。胡须是一个独特的感觉系统的一部分，高度敏感和可移动。虽然许多研究人员认为胡须可以主动感知触摸，但从未在任何动物身上进行过定量研究。海豹，海狮和海象，在黑暗和阴暗的水下栖息地使用它们的胡须觅食，导航和物体识别。它们拥有所有哺乳动物中最长和最敏感的胡须，形状特殊，有目的地系统地移动。海豹的胡须是起伏的，而海狮和海象的胡须是光滑的。这些形状特化很可能会影响动物用胡须感觉到的东西。然而，从来没有人对此进行过调查。对于这个奖学金，我将使用行为实验，3D机械模型和机器人平台来研究海豹和海狮的主动触摸感应策略。我认为控制特殊形状的胡须可以让海豹和海狮区分不同的物体。我将发现主动控制触须是否能使它们更有效地感知，从而提高我们对主动感知、触须力学和电机控制的理解。这将通过以下方式进行测试：1.描述海豹（波浪须）和南非软毛海豹（光滑须）的须运动。动物将在SeaQuarium Rhyl接受训练，以完成3种不同的任务：颜色，纹理和大小，同时蒙上眼睛并从一系列不同的干扰物中选择目标物体。胡须将在水下拍摄并跟踪，让我可以想象胡须在每个不同的辨别任务中是如何移动的。使用上述三种不同的辨别任务，识别斑海豹和南非海狗的任务特异性胡须策略。使用机械模型和机器人传感器，通过研究沿沿着施加的不同力来估计胡须形状如何影响感觉。我希望胡须形状影响胡须与物体接触时的弯曲。来自博物馆标本的解剖海豹和海狮胡须将在专业3D软件（称为有限元分析）中进行扫描和建模，以观察物体在给定情况下的行为。4.探索不同形状的胡须（波浪形或光滑）如何影响运动策略。被解剖的鳍足类动物的胡须将被连接到一个像枪口一样排列的机器人传感器上;机器人将通过移动来检测物体的大小和纹理。机器人的动作将与我的实验数据进行比较，以了解海豹和海狮的感知效率。通过结合解剖学、胡须跟踪、胡须机器人和详细的3D数字模型，这将提高我们对主动传感和胡须力学的理解。5.检查这些策略是否在水动力学任务（一些动物感知水运动的能力）中发生改变。我的触觉任务将适应水动力学任务和胡须和头部运动策略将进行比较。

Active touch theory states that sensors must move and engage in task-specific behaviours in order to improve efficiency and performance in sensory tasks. Human fingertips are an active touch system as they make purposeful, task-specific movements, for example they sweep over textures, feel around edges to judge shape and squeeze objects to judge hardness. Most mammals do not have mobile, tactile fingertips and they have whisker touch sensors instead. Whiskers are part of a unique sensory system and are highly sensitive and moveable. Although many researchers assume whiskers do active touch sensing, it has never been quantitatively investigated in any animal. Seals, Sea lions and Walruses, use their whiskers for foraging, navigation and object identification in dark and murky underwater habitats. They have the longest and most sensitive whiskers of all mammals, that are specially-shaped and are moved systematically with purpose. Seal whiskers are undulating while sea lion and walrus whiskers are smooth. These shape specialisations are likely to affect what the animal can feel with their whiskers. However, no one has ever investigated this. For this fellowship I will characterise active touch sensing strategies in seals and sea lions using behavioural experiments, 3D mechanical models and robot platforms. I suggest that the control of specially-shaped whiskers allows Seals and Sea lions to discriminate between different objects. I will discover if actively controlling whiskers enables them to sense more efficiently, improving our understanding of active sensing, whisker mechanics and motor control. This will be tested by:1. Describing whisker movements in Harbor seals (wavy whiskers) and South African fur seals (smooth whiskers). Animals will be trained at SeaQuarium Rhyl to complete 3 different tasks: colour, texture and size while blindfolded and selecting a target object from a range of different distractors. The whiskers will be filmed underwater and tracked allowing me to visualise how whiskers move during each different discrimination task.2. Identifying task-specific whisker strategies in Harbor seals and South African fur seals using three different discrimination tasks as detailed above.3. Estimating how whisker shape effects sensation by investigating different forces applied along the whisker using mechanical models and a robot sensor. I expect whisker shape to affect the bend of a whisker when in contact with an object. Dissected seal and sea lion whiskers from museum specimens will be scanned and modelled in specialist 3D software (called Finite Element Analysis) looking at how an object behaves in a given situation. 4. Exploring how different-shaped whiskers (wavy or smooth) affect movement strategies. Dissected Pinniped whiskers will be attached to a robot sensor arranged like a muzzle; the robot will make movements to detect object size and texture. Robot movements will be compared to my experimental data to see how efficient seals and sea lions are at sensing. This will improve our understanding of active sensing and whisker mechanics, by combining aspects of anatomy, whisker tracking, whisker robotics and detailed 3D digital models.5. Examining if these strategies are altered during a hydrodynamic task (the ability of some animals to sense water movements). My tactile task will be adapted to a hydrodynamic task and whisker and head movement strategies will be compared.