On a recent trip to the Kimberley with other rock art enthusiasts, I encountered unexpected scepticism for our unexpected white-striped flying foxes. There were two problems in the minds of these sceptics, neither of which I had even dreamed about.

1. “The depictions are not flying foxes”.

One observer thought that they looked like a row of turtles hanging from the vine!

No comment is really required here, as all my colleagues with some experience of a range of different-sized flying fox reckoned that the artist had rendered a good likeness.

2. “The depictions are not Bradshaw art”.

Apparently some observers require an unequivocal sash or tassel Bradshaw in the same panel as the animal depiction. The flying fox depictions from panels with other classical Bradshaw art that satisfy this criterion look very different to the white-faced species we described, as they all clearly represent medium-large species, not those at the small end of the range depicted in the painting.

There are more than 170 species of megachiropteran bats (megabats), which cover a size range of 50X from the 20 g blossom bats (still much larger than the smallest microbats, at ~1g)……. to the largest flying fox (1 Kg). Scale cannot accurately be determined in rock art because the artist may exaggerate the apparent size of species deemed more important. But in the present case, we know that the white-faced species is tiny because of its bunched up posture that is only seen in the smaller megabats with sufficient power/weight ratio to roost with their bodies pulled up close to their feet, into the somewhat spherical shape so accurately depicted by the artist. This posture was, for us, diagnostic of a very small megabat. It may have been distracting for us to refer to it as a flying fox, when this term is more commonly used for the larger megabats, but we wanted to a use a generally-recognisable name instead of the more technical name, megabat.

Bearing in mind the tiny size of the species depicted, the clear white stripe that is depicted on the snout of each individual is remarkable, in both the artist’s powers of observation, and the artist’s extraordinary technique for fine delineation, with some lines only a fraction of 1 mm across. These two features of the art are characteristic of Bradshaw art and no other, so it may be excessive to demand the presence of a classical Bradshaw figure with similar technique and colour in the same panel. The difficulty of using other Bradshaw art with flying fox depictions as a standard is that one becomes a victim of a double confound (i.e. diagnostic uncertainties in the standard panel, as well as a second round of diagnostic uncertainty when one tries to use the standard to identify the new sample).

Memory of Recent Indigenous Artists?

Recently I heard another objection:- that this was not ice-age art, but instead represented a voyage to Sulawesi by local indigenous artists on board a Macassar boat about 300 years ago, with a painting on return to the Kimberley using the memory of the white-striped flying fox that had been observed in Sulawesi. To me this explanation seems much more inventive than any aspects of our published account. We did cover in the paper the unlikely possibility that the flying fox had arrived in the Kimberley inside the head of an artist rather than in reality. But the crucial point concerns the identity of the artists. There are no recent examples of the very fine delineations, fractions of a millimetre across, such as those we see in that painting, nor can one find comparably accurate species depictions. The style is therefore unmistakably Bradshaw, as I have pointed out above. The main doubt therefore hinges on the age of Bradshaw art, for which there are a number of observations that support a Pleistocene age, as we argue in the paper. These observations tend to be biological inferences which conflict with the physical method of C14 measurement giving a Holocene age, around 3000 yrs, an order of magnitude smaller that the other inferences. Since we now know that Bradshaw paintings are alive with fungi and bacteria, the outlying, very young age of the C14 measurement can be explained by the fact that the tissue is not dead, which is a prerequisite to measuring the radioactive decay of C14.