There are a few issues i can see here.<p>1. (meta-science) If this result mattered, it would be published in the Journal of the Acoustical Society (JASA), which is where all the good marine mammal acoustics work is published. This appears to be a private journal of a particular russian university, which is less than convincing, and single-author papers are always (fairly or unfairly) subject to higher scrutiny. Other weirdnesses: the paper was submitted on 16 AUG, accepted the same day, and "reviewed" within 5 days. This suggests a certain laxity of rigor.<p>2. This work was done in a small highly reverberant concrete-walled pool. It would be more convincing in free-field, as much of the analysis here is tightly coupled to notions of coherency, which reverberations blow right (so to speak) out of the water. Why their analysis is done in pascals SPL and not dB re 1uPa SPL (as everyone else does) is confusing.<p>3. There is little to no quantitative analysis of spectral features in the results or discussion. There are also multiple sentences that involve the phrase "we can assume", which I would argue is certainly not the case.<p>4. That dolphin clicks are spectrotemporally complex is a boring result. The authors fail to demonstrate, and in fact basically don't even claim, the assertion in the HN title.
I am saddened by how long we've known about cetacean communications--decades--and how little progress there's been, given the giant strides tech has made in DSP and pattern matching. If only we applied a fraction of the tech effort we put into cell phones or weapons.
If (like me) you mainly wanted the conclusion, here it is:<p>> As this language exhibits all the design features present in the human spoken language, this indicates a high level of intelligence and consciousness in dolphins, and their language can be ostensibly considered a highly developed spoken language, akin to the human language.<p>And:<p>> The results obtained in this study suggest the existence of a similar highly developed spoken language in toothed whales (Odontoceti), based on the similarity of their acoustic signals and morphology.
I've wondered if dolphins speak to each other (assuming that they do) in a serial flow of abstract symbols-- words, like we do, or if they use their sonar to project 3-D 'holograms' of objects and shapes to each other.<p>Maybe even both. What a wonderful day when we crack the code.