Scientists in Belgium are investigating a farmer's claim that different kinds of music affect the behavior of his pigs.Piet Paesmans first noticed the reaction when his son started singing a song in the family’s animal shelter.The farmer said the sows, or adult female pigs, seemed excited by the sound and started shaking their little tails."I thought this was too good to pass up, we should try that with the other pigs too," Paesmans told Reuters from his farm.Paesmans has since created a list of songs to play at different times of the day.He uses energetic music when he wants the pigs to be active and lullabies at the end of the day.Lullabies are quiet, slow songs."Jolly dance songs are the biggest hits," Paesmans said.He said that the pigs even appear to dance to the music.He does not play rock and roll music for the pigs.“Rock music is too strong, they don't like it," the farmer observed.The farmer described his observations to a team of researchers.