Ultrasonics have been used in a number of biomedical and civil application ranging from medical ultrasound devices to beam deformation non-destructive testing. Ultrasonic pressure waves have been used naturally for thousands of years by animals for navigation and communication, with the prime examples being bats with ultrasonic navigation through air and dolphins with ultrasonic communication and navigation in water. This paper investigates on signal propagation within the human being by means of intra-body communications without radiofrequency waves but, instead, with lower (if not deeply lower) frequency waves. An exhaustive review of up-to-date propagation modes in water-like vectors is performed and experimental measurements allow the setting up of a comparison with conventional propagation. A practical demonstrator has been developed to characterize within a low frequency range the ultrasonic wave one-direction propagation in piece of meat.