☛ Everyday bat vocalizations are rich and complex

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.

This is brilliant. They were able to correlate their data analysis of the bats’ vocalizations with the behavior and responses that they observed… so now we know more about how bats communicate! Simply by listening to the vocalization, the context, addressee, and even “the outcome of the interaction can be predicted above chance level”. Fascinating.

From the discussion:

It is important to note that we used one set of acoustic features for classification. However, many other multi-dimensional spectro-temporal representations can be tested. The bat’s brain could thus be using some other representation that encapsulates much more information regarding different social aspects. The bat may be able to classify the context of an interaction with higher confidence, based on some acoustic feature which it evolved to use and is yet to be determined. Our analysis is thus probably only a lower bound on what a bat is capable of extracting from aggressive social vocalizations. For example, we did not include any temporal information in our analysis.

In any acoustic signal, and especially where communication is involved, the time parameter is usually crucial and will add rich layers of information. For example, just imagine taking a piece of human speech, and (a) only looking at the overal speech parameters, versus (b) observing how the speech parameters change during the speech. Case (b) will provide far more information than case (a). I think we will discover over time that bats have a pretty well-evolved communication scheme.

This is fascinating stuff.


☛ How Bayesian inference works

Bayesian inference is a way to get sharper predictions from your data. It’s particularly useful when you don’t have as much data as you would like and want to juice every last bit of predictive strength from it.

Although it is sometimes described with reverence, Bayesian inference isn’t magic or mystical. And even though the math under the hood can get dense, the concepts behind it are completely accessible. In brief, Bayesian inference lets you draw stronger conclusions from your data by folding in what you already know about the answer.

An excellent, simple introduction to Bayesian inference. This uses practical examples and an abundance of visual guides: especially useful if you don’t have an extensive math background.


Music: lyrics for Daniken, from Rupam Islam’s Notun Niyom

Rupam Islam is out with a new solo album, Notun Niyom. Continuing with tradition, here are the lyrics to Daniken from this album. (Notun Niyom is available to listen on Spotify!)

Song: Daniken
Album: Notun Niyom

gobeshona-tona tomake manaye
amar agroho sotto janaye

gobeshona-tona tomake manaye
amar agroho sotto janaye
gobeshona tumi koro e-niye
phola-phol pele diyo janiye

chola-chol kori kolpona te
abhijan tai na-hanyate
maddhom mon ar lekhoni
lupto danar shonjiboni

icche-ra shob kobita paray
bhabchi-bhabbo gondho choray
tomar icche bhobisshoter
sondhan dey notun pother

bole cholo jai se-pothe haati
eta mohakash-jaaner maati
control-e thak khoka-o-khuku
shokti utsho surjo-tuku

promaner tumi upashok tai
amar shopne tomakei chai
juktir jaale amar hridoy
obohele kore nile tumi joy

tumi ki nijeke byartho bhabo?
tomake ami e-gaan shonabo
aaloker goti amar gaane
chhutbe notun surjo-taane

tumi ki nijeke byartho bhabo?
tomake ami e-gaan shonabo
aaloker goti amar gaane
chhutbe notun surjo-taane

he-prachin, he-probin
he-aadim mohakash
lukiye rekhecho
bhule jawa itihaash

smriti-te tobu kaar
protiddhoni shunte pai
probashi aakashi
se ki kono… debota-i?

tomar totto bhaota hole
chok-choke kono rangta hole
chaota-ke ami beshechi bhalo
rangta amar rong pheralo

bhaota gaiche prithibir gaan
rangta ghochalo rashtro-nishan
aami prothagoto dhormo-bihin
aami gaai Lennon-er Imagine

moha purushera tader juuge
chole-asha rewaj-er hujuge
bhondo akkha peyei thaaken
Jesus Christ-o krush-e jhulechen

ekdin tumi patta pabe
tomar totto proman hobe
shopno sophol hobe amar-o
tokhon amay khujte paro

ekdin tumi patta pabe
tomar totto proman hobe
shopno sophol hobe amar-o
tokhon amay khujte paro

he-prachin, he-probin
he-aadim mohakash
lukiye rekhecho
bhule jawa itihaash

smriti-te tobu kaar
protiddhoni shunte pai
probashi aakashi
se ki kono… debota-i?

debota-i?


Music: lyrics for Haowaay Pa, from Rupam Islam’s Notun Niyom

From Rupam Islam’s new solo album Notun Niyom, here are the lyrics to Haowaay Pa. (Notun Niyom is available to listen on Spotify!)

(P.S.: I really don’t like the spelling ‘haowaay’, so: here’s ‘Hawaye Pa’ by Rupam Islam.)

Song: Hawaye Pa
Album: Notun Niyom

phirbo na, ami phirbo na
shunechi je daak nishachori-r

phirbo na, ami phirbo na
shunechi je daak nishachori-r
karnish bohu-tol, halka chokher jol
tar cheye halka sarir

jibon amar kache ekhono lukiye achhe
jibon ki somoyer daash
hawaye pa, amar hawaye pa
ar batashe amar biswas

jibon amar kache ekhono lukiye achhe
jibon ki somoyer daash
hawaye pa, amar hawaye pa
ar batashe amar…

arekbar, hya arekbar
ghum ar tondrar shima-rekhaye
dekhi nishachori tumi eshe dakcho jemon kore
megh brishti ke deke jaye

arekbar, hya arekbar
ghum ar tondrar shima-rekhaye
dekhi nishachori tumi eshe dakcho jemon kore
megh brishti ke phire chaye

nishachori tumi eto akorshoniyo
je shudhu tomar prorochonaye
hawaye pa, amar hawaye pa
dilam hawaye pa nirdidhaye

jibon amar kache ekhono lukiye achhe
jibon ki somoyer daash
hawaye pa, amar hawaye pa
ar batashe amar biswas

jibon amar kache ekhono lukiye achhe
jibon ki somoyer… daash
hawaye pa, amar hawaye pa
ar batashe amar…