The most remarkable aspect of night time on the farm is just how busy the place is! Kangaroos and wallabies grazing in the paddocks, owls, frogmouths, plovers all busy with the business of hunting and defending their territory. Flying foxes, those huge furry bats, feasting on blossoms of the forest in season and the fruit in our orchard. Tiny microbats flitting here and there, gorging themselves with insects on the wing.
And amongst all the native wildlife are the cattle calling to each other in the distance, the occasional fox yelping in the undergrowth, and here on our farm, the horses grazing with the marsupials, happily ensconced snout - deep in juicy green grass.
All this busy animal action in the middle of the night leads me to wonder how these creatures see what they are doing. It is well known that many animals possess extreme night vision: horses can gallop through rough country guided only by a faint crescent moon, and not put a hoof wrong. Kangaroos can bound through the undergrowth at night, never catching themselves in a branch. The way animals see the world is, we know, very different at times from the way humans see the world.
Owls, the pin up critters of the night, have specially adapted eyes that give them fabulous night vision. The shape of the eyeball is tubular and if it was a camera lens it would be rated at about F1.1, a very fast lens indeed. Add to this a vast number of retinal cells specialising in dark vision and you have an eye that is perhaps 300 times more sensitive to faint light than the human eye. Some snakes have tiny pits on their heads which detect infrared light in a crude way but nonetheless give the animal a view of the world in IR. Arctic dwelling creatures such as reindeer and Arctic foxes as well as hunting birds can see light in the ultraviolet as can many insects.
So, here's a questiion: What do these creatures see when they look up at the night sky above their heads? Last night I took a picture of NGC 253, the silver coin galaxy in Sculptor. It is below the limits of human visual detection - just. In fact some people have claimed to have seen it from dark sites. What does my horse see when he glances up? I would say that he sees the galaxy, extending the length of the moon, glowing an obvious. In fact when he looks around the sky he sees many galaxies: low in the north is the enormous Great spiral in Andromeda, now he sees the hamburger galaxy, Centaurus A, glowing brightly above him. And he cannot fail to miss the sweeping dusty glow that wreathes Orion.
And what do those animals blessed with infrared and ultraviolet vision see? Great swathes of the milky way unseen by mankind until the last few decades, hidden by dust and only detectable in infrared. Quasars glowing like fireflies in the ultraviolet, commonplace sights to UV - sensitive reindeers (of all things!) and insects alike.
The sky above is a very different view to our animal friends. Brighter, more exotic and in fact more information - laden. It has been known for decades that migrating birds steer by the stars at night and the sun during the daytime. But imagine animals navigating by Quasars! In fact Quasars form the most stable reference points for navigation in human satellite systems. And it is wonderful to imagine that our animal friends have been using Quasars as travel beacons for aeons!