Drinking and Driving

Sunghwan (Sunny) Jung, Cornell University


Fluids are vital to all life forms, and organisms presumably adapted their behaviors or features in response to mechanical forces to achieve better performance. In this talk, I will discuss two biological problems in which animals exploit mechanics principles. First, we investigated how animals transport water into the mouth using an inertia-driven (lapping) mechanism. Dogs accelerate the tongue upward (up to 4 g) to create a larger water column while drinking, whereas cats use a tongue motion with relatively small acceleration. We found that, in order to maximize the water intake per lap, both cats and dogs close the jaw at the column beak-up time governed by either unsteady or steady inertia. In the context of animal drinking, I will also talk about how bats drink water on the wing from a mechanics point-of-view, and illustrate an on-going design work to develop a bat-inspired vehicle to monitor the water quality along rivers or lakes. Second, we studied how birds with long slender necks plunge-dive and survive from the impact. Physical experiments of an elastic beam as a model for the neck attached to a skull-like cone revealed the limits for the stability of the neck during plunge-dive. We found that the small angle of the bird’s beak and the strong muscles in the neck predominantly reduce the likelihood of injury during high-speed plunge-dive. As a bio-inspired engineering, we design a bird-inspired projectile to explore underwater without propulsive mechanisms