PSH's picture

Indonesian bats

Observed: 16th December 2011 By: PSH

I would be most pleased if you could perhaps identify the phenomina I captured with still photos while in Indonesia recently. In picture 001 there is an extremely long 'tongue' like extension from the bat, however when zooming in it appears to me that the bat is not facing in the direction of the 'tongue'. In picture 002 the same tongue type extension can be seen from the bat but as it is further away from the camera the extension is less clear, but visable none the less. I took many photos in this location, all using flash as I was inside an unlit temple, the 'tongues' are not existing marks on the temple wall as they only show on photos eminating from bats?

Species interactions

No interactions present.


DavidHowdon's picture

Exposure time

The exposure time on your pictures is 1/8th of a second - that is quite slow.

What was the curtain setting on your flash?

Sort of looks like the 'tongue' is the just visible trail of the bat's body beyond the frozen clear image that the flash showed up.

PSH's picture

Bat trail?

Thanks for your comment David. I cant remember what setting I had my camera on, as I was in almost total darkness with just a little light creeping in the entrance near my feet, I couldnt see anything. I took dozens of pictures just hoping to catch shots of bats which I could hear fluttering around me. I'm not convinced the 'tongue' is a blur of the moving bat, for one it sems to be ahead of the bats and looks like a straight line, and second I would expect the bat itself to be blurred too? But I dont know, hence posting here!

Thanks David for your input. Anybody else any ideas?


DavidHowdon's picture

To explain a bit more clearly what I meant

The usual default setting for cameras is to flash at the start of the exposure. Say the flash itself lasts 1/200th of a second.

So in your case it would be open of 1/8th of a second (the shutter setting recorded in the EXIF information in your images) so the shutter would be open 25/200ths of a second.

However there would only be bright light (the flash) for the first 1/200th of that time. This would freeze a bright clear image of the bat which can be seen in your picture.

However after this (for the next 24/200ths of a second) the shutter remains open with only ambient light (very little). During this time the bat moves forward but is not making a clear image on the sensor (i.e. it is just a faded smear). As the bat is flying foward this will be in front of the clear image of the bat which was frozen at the start of the exposure.

Not sure it is this of course but seems the most plausible explanation to me.

PSH's picture


Thanks David for a very thorough explanation, I cant find any reason why I cant accept that as what my photos have captured, though I'm a little surprised the shutter remaining open after the flash has captured what looks a well defined long line and not a blury line at least the size of the bats body, presuming the wings moving far to quickly to show. But thats probably my lack of knowledge of photo exposure princibles.

Thanks David, I think your explanation is by far the most likely explanation of what I have captured in the photo.

Many thanks

DavidHowdon's picture


It might be worth putting your pictures up on a dedicated photography forum and asking there. I'm far from an expert on the functioning of cameras and I suspect someone on such a forum would have a better view on exactly what happened.

PSH's picture


Thats a good idea, David, I'll have a hunt around for photography forum.

Thanks again.


DavidHowdon's picture

Did you ever

get any further in finding out what this was?