Pachyderm Polka?

There is a report (http://www.guardian.co.uk/science/2008/nov/17/elgar-elephants-classical-music-wildlife) on work carried out at Belfast zoo claiming that four female Asian (the pictured animal is an African elephant and might well have different musical taste) elephant showed reductions in 'aggressive' and stereotyped (e.g. swaying and trunk tossing) as well as increases in 'normal' behaviour after exposure to classical orchestral music by Elgar, Strauss etc. Apparent beneficial effects of music in a wide range of animals (cats, dogs, cows and horses) are not uncommon but what seems to have been 'played down' in this study is the fact that the elephant would not hear the music in the same way as ourselves. They would not detect some of the higher frequencies but might well pick up sounds that were lower than those responded to by humans. It is also unclear why (as claimed by the author) these sounds would help this widely-ranging species deal with the confines of its enclosure. Perhaps they should be played elephant sounds or heavy metal?