Courtesy of Sci-News:
Naked mole-rats (Heterocephalus glaber) form some of the most cooperative groups in the animal kingdom, living in multigenerational colonies under the control of a single breeding queen. Little is known about how individuals within these colonies navigate the many interactions that must occur in such a complex cooperative group. A new study shows that calls emitted by individuals, in particular the common ‘chirp’ call, convey information about group membership, creating distinctive colony dialects; what’s more, these dialects are culturally transmitted across generations, supporting the idea that social complexity evolved concurrently with vocal complexity.
[…] To investigate the role of vocal communication in mole-rat society, Professor Lewin and his colleagues recorded a total of 36,190 chirps made by 166 individuals from seven naked mole-rat colonies held in labs in Germany and South Africa. They then applied machine learning techniques to analyze the acoustic properties of these vocalizations. “We wanted to find out whether these vocalizations have a social function for the animals, who live together in an ordered colony with a strict division of labor,” he said.
The researchers found that naked mole-rats have distinctive soft chirps, unique to an animal’s group, and that this dialect is determined by a colony’s queen and is learned by mole-rat pups early in life. However, these dialects are not fixed; they change when a colony’s queen dies and is replaced, and young pups fostered in foreign colonies learn the dialect of their adoptive groups. This suggests that individual colony dialects, including their transmission from generation to generation, is cultural rather than genetic.
“We established that each colony has its own dialect,” said first author Dr. Alison Barker, also from the Department of Neuroscience at the Max Delbrück Center for Molecular Medicine. “The development of a shared dialect strengthens cohesion and a sense of belonging among the naked mole-rats of a specific colony.”
“Human beings and naked mole-rats seem to have much more in common that [sic] anyone might have previously thought,” Professor Lewin said. […] “The next step is to find out what mechanisms in the animals’ brains support this culture, because that could give us important insight into how human culture evolved.”
I’m generally skeptical of animal-language stories, but this seems reasonably plausible, though I don’t know about “insight into how human culture evolved.” Thanks, Jonathan!
Everyday bat vocalizations contain information about emitter, addressee, context, and behavior
Yosef Prat, Mor Taub & Yossi Yovel
Animal vocal communication is often diverse and structured. Yet, the information concealed in animal vocalizations remains elusive. Several studies have shown that animal calls convey information about their emitter and the context. Often, these studies focus on specific types of calls, as it is rarely possible to probe an entire vocal repertoire at once. In this study, we continuously monitored Egyptian fruit bats for months, recording audio and video around-the-clock. We analyzed almost 15,000 vocalizations, which accompanied the everyday interactions of the bats, and were all directed toward specific individuals, rather than broadcast. We found that bat vocalizations carry ample information about the identity of the emitter, the context of the call, the behavioral response to the call, and even the call’s addressee. Our results underline the importance of studying the mundane, pairwise, directed, vocal interactions of animals.
`Indeed, nearly all of the communication calls of the Egyptian fruit bat in the roost are emitted during aggressive pairwise interactions, involving squabbling over food or perching locations and protesting against mating attempts (Supplementary Videos S1–S4)…’
Prat, Y. et al. Everyday bat vocalizations contain information about emitter, addressee, context, and behavior. Sci. Rep. 6, 39419; doi: 10.1038/srep39419 (2016) http://www.nature.com/scientificreports
Indeed, nearly all of the communication calls of the Egyptian fruit bat in the roost are emitted during aggressive pairwise interactions, involving squabbling over food or perching locations and protesting against mating attempts
‘Ere! You lookin’ at my bat?
Fruit bat communication sounds like email: there is the ‘from’, ‘to’ and the ‘subject’ line.
Indeed, nearly all of the communication calls of the Egyptian fruit bat in the roost are emitted during aggressive pairwise interactions, involving squabbling over food or perching locations and protesting against mating attempts
This is true of humans as well (“‘Ere! You lookin’ at my old bat?”). The main difference is that humans write books preserving their squabbles for posterity.
“The next step is to find out what mechanisms in the animals’ brains support this culture, because that could give us important insight into how human culture evolved.”
The excerpts about naked mole-rats and fruit bats describe and interpret behavior. They say nothing about how that behavior “evolved”. So they suggest nothing about how human culture “evolved”.
Who addressed whom – recognizing the emitter and addressee:
The emitters of the vocalizations were clearly identified with a balanced-accuracy of 71% (where chance level was 14%… indicating that, potentially, a bat could acoustically recognize who is addressing it… This implies that an eavesdropping bat is theoretically able, to some extent at least, to identify if individual A is addressing individual B or individual C. [Me, you, (s)he? The authors don’t seem to claim that bats have proper names. I think there may be some evidence for this for dolphins but I’m no expert.]
Perhaps we will be able to answer the age-old questions “Do cats eat bats? Do bats eat cats?”
There’s no such thing as perfect transmission, so anything but the development of dialects would be surprising. If there’s a point to note, it’s that the dialects are unique on a colony level and conforming to the reigning queen. Individual signals diverge after the queen dies and converge again when the new queen is in place
There’s no claim that mole rat vocalizaion amounts to language rather than a signaling system, but I agree that it’s likely that similar cognitive and social mechanisms are involved in transmission of human language,
There’s no claim that mole rat vocalizaion amounts to language rather than a signaling system.
I think you’re underestimatIng what is involved in a “signalling system”. Whatever you mean specifically by that, the expression serves here at least as something contrasted with “language”. It resembles “language” but is more primitive and possibly something completely different despite the resemblances.
Consider the complex phenomena of “virtue signalling” and of ascribing that behavior to people (i.e. signalling that they are exhibiting it).
It has proved useful to analyze both “language” and “signalling system” in terms of “communication”. See Foerster (non-trivial machine), Morin (La méthode de la méthode), Luhmann et al.
Oops, the title of the first volume of La méthode is La nature de la nature, not La méthode de la méthode. It’s been a while since I read it. Just think Edgar Morin.
I agree that systems of vocal signals like those found here share properties with language. I’m even fairly optimistic about finding systems that do meet criteria of languageness in other species, but what is described in mole rats* so far isn’t that. The fruit bats above are closer, and quite possibly some social birds.
So, what are those criteria of language? I don’t think there’s one good definition of language out there, but one element of any definition should be that it’s open-ended, i.e. it can at any time be extended in any direction by any user to communicate about any experience or intention. Pirahä duly excepted.
*) I forgot to say that the mole rat forms colonies of 6.022×10²³ members.
*) Ha!
I was wondering if the naked mole rat could compete with the Holy Roman Empire by being neither naked nor moles nor rats, but it turns out that they actually are quite naked.
It’s pejorative to talk about dialects, right? These are mole-rat *languages*, navy or no navy.
They tried to build a burrow all the way to the center of the earth…
It sounds like H. glaber is capable of saying “long live queen Victoria”, and when queen Vic dies, they start saying “long live queen Liz”.
It sounds like they are not capable of communicating anything like “hey Barry, yesterday i found some delicious roots in corridor 4c, how about we go there this afternoon for a bit of a snack.”
I think another vital criterion of human language is arbitrariness, extending as the default right across the language. There’s no reason at all why “dog” should be represented by /ʃjɛ̃/, /hʊnt/ /dɔg/ (twice) /kare:/ /ba:/ /kalb/ …
As far as I know, no animal signalling system has this degree of sheer arbitrariness (though admittedly this may in some cases provoke the question, How can we know?)
Closer to things like this business of molerat “dialect” is the undoubted crosscultural human variation of paralinguistic behaviours, like facial expression and gesture, which do vary but in a vastly less arbitrary way than language.
What animal communication isn’t arbitrary, though? As the Cheshire Cat said, “You see, a dog growls when it’s angry, and wags its tail when it’s pleased. Now I growl when I’m pleased, and wag my tail when I’m angry.”
Me: *)
And now I remembered my source: A mole of moles.
The Author of the Acacia Seeds. And Other Extracts from the Journal of the Association of Therolinguistics
https://xenoflesh.files.wordpress.com/2017/03/ursula-k.-le-guin.pdf
`For it is simply not possible to bring the critical and technical skills appropriate to the study of Weasel murder mysteries, or Batrachian erotica, or the tunnel sagas of the earthworm, to bear on the art of the redwood or the zucchini….’