Tickling Rats

Re “A Little Kootchie-Kootchie Koo and Rats Get Giggles, Tests Find,” May 4: Psychobiologist Jaak Panksepp’s tickling research with rats shows us an animal capable of “primitive, childlike joyfulness.” How can society allow animal research to continue when even the lowest rung on the ladder is shown to be a creature capable of emotions like joy and by extension, fear or sadness?

JEAN LOWE, Encinitas