Sepia is a variety of this 3-letter defensive secretion produced by cephalopods
Animals of control (20 mice) (injected intraperitoneally by saline, for 3 days) and... [DOC] [TLE] Molecular identification of alarm cues in the defensive secretions of ... [PAR] Thus, the defensive secretions, ink and opaline, specifically act as alarm cues to 
nearby con- ... three molecules together are necessary and sufficient to produce 
alarm responses.