Once a koala is down on the ground and encounters a road, things really become seriously dangerous and complicated for them. What is a road to a koala?
A bitumen road (or even a gravel road) is a foreign surface for an animal that was already not doing so well on the ground. The koala may hear a car approaching, but what does the koala brain do with this information?
I will talk about their hearing and mechanical noises in another post, but for the purpose of this post it is fair to say that hearing a car and knowing you are in its path becomes a more complex calculation than you might think. As humans we know that a road means the path a car will travel along, the rules it will travel by (eg speed limits and which side of the road, depending on the direction being travelled), and we know what a collision with a car will mean.
Because of these facts, we can use executive thinking skills to quite quickly decide if it safe to cross a particular road. We know it takes some mathematical calculation ability, and we know that a person affected by alcohol is unlikely to calculate this correctly either as a pedestrian crossing a road, or as a driver encountering a pedestrian suddenly.
We also know that many scientific studies have assisted governments to determine safe driving speeds on different roads by calculating the time it would take to stop a vehicle in an urgent situation according to the environment and the road conditions.
Let’s get back to the koala who is down on the ground, with their front-facing eyes and their mind on getting to the next safe food tree. That koala does not have the kind of sense of danger a prey animal is wired to use when moving about, and so they focus on where they are going.
To the koala, a car approaching, when it is say 50 metres away, even if they can see and hear it, is unlikely to register as a threat to them. They are unlikely at this point to even consider that it is on a course that will cross their path, even though they are on a road. If we consider the speed the car is moving at, then a car moving at 100kph that is 50 metres away will be on top of the koala in less than 2 seconds. There is no chance for the koala to calculate this and be out of the way in time.
Let’s add another layer of complexity. The image above shows an intersection literally on a boundary of Koala Gardens. I want to examine a few important features as they are common roadside features our koalas deal with all over the NSW East Coast.
Firstly the amount of vegetation very close to the roadside is typical and an important consideration for the koala. If a koala was in the vegetation on either the front right or on the opposite side of the road the driver would not see it as the vegetation is far taller than a koala. This will also mean that the koala cannot see any car until it emerges from the vegetation at which time the koala is literally on the road. The speed limit here is 80kph, so if the koala emerges and a car is 50 metres away, there is 2.25 seconds for the koala to get out of the way.
To the brain of a koala, an approaching car that went right past when it was sitting beside the road is no different, in terms of danger, than the approaching car when the koala has moved forward slightly and is now on the road.
There are no lights on country roads, so at night, unless the koala looks directly at an oncoming car, they are very difficult for the driver to see. There are often thick fogs at night on these country roads which reduces vision for both the driver and the koala. This is why we have road signs advising of known native wildlife, asking drivers to take extra care.
We have seen no evidence to suggest that koalas learn about road safety, or that they teach it to their young.
Finally we are not seeing enough evidence that people truly care about our wildlife. This roadside sign is typical of the kind of vandalism we often see here, but shows a lack of empathy and understanding of how desperate the koala situation is.