ABSTRACT
In the reported study we demonstrated how a harbor porpoise controls its velocity to catch fish. This behavior has been little studied among porpoises; specifically, there is no knowledge about the feeding process. This experiment was conducted in a controlled setting because of the difficulty of observing a porpoise’s behavior in the natural environment. Consider the case as an animal approaches a surface. The ratio of the distance between the animal and the surface to its velocity provides a first-order estimate of its time-to-contact with the surface. This ratio picked up in perceptual flows is defined as tau (τ) obtained by Equation 1 : https://www.w3.org/1998/Math/MathML"> τ ( x ) = x x ˙ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003417972/911d4425-d6db-4df9-83f6-2c38e1a83225/content/equ18_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
