The Grampians

Yesterday evening (21.4), just on dusk, my wife, my sister and my two children were returning to the silver falls carpark. By the time we were ready to get in the car it was almost dark (6.45pm). We heard a deep and protracted moaning sound. It started with a deep throaty, kind of guttural sound and shifted into a more moaning sound. It seemed about 100m away and positioned half way up a steep slope, on the opposite bank of the river, though from a position that could easily overlook the carpark. Both my daughters said it sounded like a lion. Thinking that it was obviously not a lion I thought it was more likely to be cow – on the assumption that it was clearly coming from a large animal (which in my mind excluded it being a koala, wallaby or kangaroo) which therefore could only have been a cow. Although after a moments reflection I also knew that a cow could not have been at such an inaccessible region on the mountainside. We joked that it must be a yowie. We heard the sound several more times before we got in the car (I was loading three mountain bikes in the back). Although the event intrigued us all I quickly forgot about it on the drive home. 
This morning, at about 7.15 I was standing outside our cabin with my sister, a kilometer outside of Halls Gap on the road to Silver Band Falls and she said she could faintly hear the same sound. Then I heard it again several times. I pulled out my mountain bike and rode along to the end of Tancara st(?) and followed the walking tracks towards the Aboriginal Cultural Centre to where the track finished. I could hear the sound more clearly but it was still in the distance (now over a kilometer from the cabin). Again I thought that such a deep groaning sound seemed to be coming from an animal of considerable size to travel such a long distance but I couldn’t think of any native Australian animal that makes such a sound. I estimated that the sounds were at least several hundred metres away in the direction of the path that lead towards the cultural centre. I estimate this would place the source of the sounds not more than a few kilometers from Silver Band Falls.  
 After arriving back in Melbourne I thought, just out of curiosity, I’d search the net to see if any strange animals have been sighted in the Grampians (I had never been there before). That’s how I came across your email and the history of large cat sightings in the area. As far as I could tell the sounds were consistent with an animal that size.
 Just thought I’d put on the record,Thanks,John