Apparently humpback whale songs show a few features in common with human language; such as being culturally transmitted through social interactions between whales.

"The authors found that whale song showed the same key statistical properties present in all known human languages" - my guess is that the author talks about Zipf's Law, that applies to both phoneme frequency and word frequency in human languages.

[Dr. Garland] "Whale song is not a language; it lacks semantic meaning. It may be more reminiscent of human music, which also has this statistical structure, but lacks the expressive meaning found in language." - so while it is not language yet it's considerably closer to language than we'd expect, specially from non-primates.