some researchers have concluded that in order to communicate with extraterrestrial species, humanity must first try to communicate with earth's intelligent animal species. john c. lilly worked on with interspecies communication by teaching dolphins english (successful with rhythms, not with understandability, given their different mouth/blowhole shapes). he practiced various disciplines of spirituality and also ingested psychedelic drugs such as lsd and (later) ketamine in the company of dolphins. he tried to determine whether he could communicate non-verbally with dolphins, and also tried to determine if some extraterrestrial radio signals are intelligent communications. similarly, laurance doyle, robert freitas and brenda mccowan compare the complexity of cetacean and human languages to help determine whether a specific signal from space is complex enough to represent a message that needs to be decoded.