Soft rock geophysicists map the Earth’s subsurface in Two Way Time, that is the time it takes for a seismic signal to reach a reflector from the surface and return again to a sensor.  Hard rock geophysicists use other processes like gravity and magnetics to map igneous and metamorphic rocks. 

While interpreting and mapping their data, that interpreting geophysicist thinks in Time, only vaguely aware of what differences velocity will make to their final depth maps.  It has been the bane of engineers for decades, but perhaps they can learn from bats.  Yes, bats apparently also work in time, not distance.

A pair of researchers has published a paper in PNAS explaining that they have raised bats in a helium (He) rich atmosphere and compared their locating abilities with regular bats.  In the He rich air, both sets of bats underestimated the distance to the target in a similar fashion, leading to the conclusion that bats have an innate sense of the velocity of sound in air.

I must admit, I am a bit puzzled by the conclusion.  Surely the speed of sound in air is not a constant but depends on air temperature, density and humidity.  Wind speed and dust are also likely to play with a bat’s ability to judge the time (distance?) to fly to an object. So what speed is innate?

If bats work in time, then all they need to know is the flying time that is necessary to reach the particular stationary object.  A bat probably doesn’t understand the concept of distance or velocity as they have no distance measuring instruments; as opposed to engineers who have distance measuring implements, but no concept of time.

So does a He rich atmosphere simply create a problem with a bat’s own perception of its own flying speed, or in its view, the time it will need to get to a particular object?

I reckon that there are a lot more questions to ask.

Can a bat judge the time to an object when there is a heat source in its path generating a column of hot air for example? Velocity of sound in air increases at about 1 m/sec for every degree Celsius increase.

Do arctic bats have trouble flying in the tropics?

When chasing a flying object, a bat must regularly calculate the object’s revised position in time.  Does He affect this ability?

What is the consensus?  Do bats understand velocity and have an innate knowledge of the speed of sound in the atmosphere at large?