Bat calls, “songs” to keep to the theme of this blog, are hardly inarticulate shrieks. In fact, bat echolocation calls are finely honed sonar pulses and have a complex and time-varying structure. The audio and rather low-resolution spectrograms in my earlier postings should hint at that.
There’s a fair amount of interesting scientific research out focusing on bat echolocation, in a much more systematic and detailed way. I was delighted to find not only the article below, but an entire on-line journal whose content is completely free, readily accessible, and freely redistributable.
For example, the graphic at the top of this post, which shows the frequency composition of several individual bat calls, comes from The Voice of Bats: How Greater Mouse-eared Bats Recognize Individuals Based on Their Echolocation Calls.
The authors here show that in addition to all the sonar ranging information encoded in bat calls, there are also individual differences and these differences are recognizable to other bats. They say:
Animals must recognize each other in order to engage in social behaviour. Vocal communication signals could be helpful for recognizing individuals, especially in nocturnal organisms such as bats. Echolocating bats continuously emit special vocalizations, known as echolocation calls, and perceive their surroundings by analyzing the returning echoes. In this work we show that bats can use these vocalizations for the recognition of individuals, despite the fact that their main function is not communication.
Yovel Y, Melcon ML, Franz MO, Denzinger A, Schnitzler H-U, 2009 The Voice of Bats: How Greater Mouse-eared Bats Recognize Individuals Based on Their Echolocation Calls. PLoS Comput Biol 5(6): e1000400. doi:10.1371/journal.pcbi.1000400
Now the abilities of at least some bats to recognize one another’s songs is an interesting finding in itself, but what I really like about this article is the philosophy of open research enabled by the journal in which it appears. The articles in the Public Library of Science Journal Computational Biology are freely available under a Creative Commons License. You can download them, read them, comment on them, and upload them to your own site, as long as you accurately attribute them.
I don’t know if you’ve ever had the misfortune to try to download an article from some of the more Intellectual Property-obsessed scientific publishers, but it can be a real hassle. I recall one attempt to buy an article on Organizational Psychology from a well-known publishing house. My wife was in a red-hot hurry for this article in preparation for a job interview the next day.
Not only was the e-commerce part of the web site needlessly complex and cryptic, but when the article for which I paid $35 never arrived as promised by e-mail, we began a saga of phone calls and e-mails that spanned two continents. Turns out that the reason they didn’t answer the number provided for technical problems during what seemed normal business hours here in EST was that the number rang in the UK.
Someone from the UK eventually returned the call a few days later, and ultimately my card was credited for the purchase price. It seems that once again, one publishing house had acquired another, and the integration wasn’t going smoothly (surprise, surprise). By the time all this was complete, we could easily have gone to the college library and photocopied the article, and for about $33 less, too.
We never got the article. Congratulations old-line publishing house, your intellectual property is safe — so safe that even those folks who might, out of desperation, pay your inflated prices can’t get it.
PLoS is a pleasant change of pace. I think folks like this, along with the legions of scientists who understand that science benefits when information is shared, and not when it is hoarded, will gradually drag the old-line publishers into the post-copyright age, but if my experience is any guide, it may be painful and slow.
In the meantime, let’s celebrate the availability of open-source research to complement our open-source software.
Now which bat was that I just heard — I could almost make out little Vlad’s call…