1. A device, for determining at least two attributes of an animal tissue using acoustic energy, comprising: an acoustic receiver module that receives acoustic energy that has been reflected from the animal tissue, and outputs an electrical signal based on the received acoustic energy; a processor that is configured to process the signal so as to generate values of the at least two attributes of said animal tissue, said attributes being selected from the group consisting of an amplitude-variations-with-offset characteristic, a signal trace characteristic, a spatial characteristic, and a spectral decomposition characteristic; and a computer storage configured so as to store the values of at the least two attributes of the animal tissue.