(NewsNation) As the manhunt for Grant Hardin continues, Dave Canterbury, an expert on wilderness survival, said he believes the "Devil in the Ozarks" is prone to slip up sooner rather than later.The longer he goes without food, the longer hes wet, the longer hes not sleeping well at night, the more apt he is to make mistakes, said Canterbury.Hardin escaped Sunday from the North Central Unit in Calico Rock, Arkansas, where he was serving 80 years for murder and sexual assault. Hardin, a former police chief, had been held there since 2017 and reportedly escaped after a corrections officer let him out.Arkansas mayor and murder victims sister reacts to prisoner escapeThe search has now reached several days, and Canterbury said he believes that neither the landscape in northwest Arkansas nor Hardin has a distinct advantage."I think it's a toss-up," he said. "You've got a lot of boots on the ground, so the terrain can be covered. The problem that you have is the chance of mechanical injury. You have the weather, you have the bugs."Canterbury said the weather could significantly influence whether Hardin might soon give up."Well, he's going to have to have some kind of heat source," he said. "He's in terrain where he's going to be wet all the time. Even if temperatures only dip down into the 60s at night, he's going to be cold. And that's a recipe for hypothermia."Mom shot man trying to rape her 12-year-old daughter: Court documentsGiven the number of caves in the area where Hardin is hiding, Canterbury said it would be smart for him to avoid them at all costs."He can't live in those caves," Canterbury said. "He's got to come out sooner or later."Canterbury said he believes Hardin will eventually be found in a cabin in the area, trying to gather supplies.