Long time no post! I’ll restart blogging by posting about some science and meta-science I recently read about. This post is about the sciency parts.
A study in PLoS Biology about echolocating bats found that the bats move their ears in a way that enhances the acoustic cues they need for localizing sounds. Does that now count as doubly active sensing – echolocation plus sensor movements?
Another interesting study I read was on ant navigation. Before hearing about it, though, you need to know about the ant odometer, or ‘ants that count’:
Cool, eh? Now the recent study shows that odometry is not the only way ants can navigate – for the special case that one forager carries another ant to a different nest, the carried ant has no idea about the steps taken. The researchers showed that the carried ant can navigate relying only on optic flow cues, and that these cues cannot be integrated with the odometer.
How to make a virtual reality setup more real
Using a virtual environment to examine an animal’s responses has many advantages – among other things, every environmental parameter can be controlled, the animal can be kept stationary for instance for optical imaging of neural activity. However, one mustn’t forget that it is not the real thing – as it says on the tin, it is a virtual environment! (And as a researcher working in a lab exploring the vestibular system, I am particularly puzzled that vestibular inputs seem pretty neglected.) If no one looks at the real thing, how can you know that the animal’s responses are the same? So there are some efforts underway to make some virtual environments more ‘real’ – one ingenious way to do this is described in this study: you move the environment about the animal!
Number of bacterial cells in our bodies
Finally, you probably have heard that our bodies contain 10 times more bacterial cells than human cells. Well, this study looked again and found that according to the latest estimates, it might be the same order of magnitude after all – in other words, there are about as many bacterial cells as human cells in a typical human body (about 10^13 each in a 70kg reference man, but the bacterial cells only weigh 200g altogether!).