Volunteers with Land Search and Rescue New Zealand Photo: Land Search and Rescue New Zealand
With steep mountains, wild rivers, and swift weather changes, Aotearoa is a place where people can easily lose their way.
Although Kiwis are fortunate to have NZ Search and Rescue, these skilled and brave volunteers can't always perform miracles.
To better predict what people tend to do when lost on land, search-and-rescue scientist Dr Robert J Koester has studied thousands of cases. He talks to Jim Mora about his life's work.
Listen to the interview
Robert J Koester - search-and-rescue researcher and the author of Lost Person Behaviour Photo: Supplied
Dr Robert J Koester is a biologist, specialising in neuroscience. He developed the software FIND and the International Search and Rescue Incident Database (ISRID). He is the author of Lost Person Behaviour.
Most people who are lost in the wilderness, especially if they're also injured, will be found close to what's called a ‘linear feature’, Koester says – a stream, a trail, a road or something else that “you can kind of naturally follow”.
Over the years, he says the behaviour of lost hikers, who usually kept going when they mistakenly think they're still on a trail, has been altered only by personal devices.
"When they're lost, they're more likely to go uphill, in pursuit of a cell phone signal."
The "traditional" behaviour of lost hunters has also changed in recent years, Koester says, due to the challenges of increased age.
"[In the past] the most typical [lost] hunter scenario was they made a kill and they're following the blood trail to find the animal. They're so intent on that they're not paying attention to landmarks and they get lost.
"[Recently] they tend to be a little bit more elderly and they have a medical problem or they have a trauma problem – falling out of a tree stand or accidentally shooting their foot or falling off a cliff. That's a newer trend I have noticed."
People with dementia who get lost tend to "go until they get stuck", Koester says.
"If they're on a relatively straight trail or road, they may go a considerable distance. But if the road takes a sharp turn, or if there is [what they perceive as] 'a perfectly good road', they may walk straight across it. Then when the bush gets really thick and kind of grabs them, that is where they'll stay. They usually won't turn around and back out as somebody with typical neurological function would."
Other cognitive challenges such as autism, despondency and substance intoxication can help predict how a lost person will behave, he says, and of course age.
Children love to take 'shortcuts' that aren't usually the shortest distance between two points and they're willing to go off a trail as part of their play.
"They do have the same spatial abilities as adults but they're not refined so it's easy for them to make mistakes. Their preferred pattern is to latch on to a linear feature and follow it."
People who get lost in the wilderness act in quite different ways depending on why they're out there in the first place, Koester says.
What to do if you get lost
If you get lost yourself, his best advice is to stay put.
"You'll conserve your energy, you won't do anything stupid, you won't make the situation worse. It'll give you time to make a shelter, hopefully make a fire, do all the things you need to survive without expending more energy.
"The one caveat on that is hopefully you've told somebody where you're going and when you hope to get out of the woods because if no search gets started for you, that's going to be a problem too."
Most people – with the exception of "skimpily dressed" runners – can keep themselves alive for at least 24 hours outside, he says.
"Maintaining your body heat is probably the most important thing."
Koester has been lost in the bush himself but with a map and compass he was able to use effectively.
He describes map-reading as "a perishable skill that needs to be practised".
"I certainly always have a GPS with me. But to keep my skills up, I'll try using my map and compass first. Then after I'm reasonably sure where I am on my paper map, I'll pull up my GPS and just double-check myself."