12 mistakes you're making when visiting national parks, according to a former park ranger of 37 years

Tom Haraden worked in the National Park Service for 37 years.

Monica Humphries/Business Insider

• Visitors make avoidable mistakes when visiting national parks, a former ranger told Business Insider.
• Tom Haraden spent 37 years protecting visitors and wildlife in nine national parks across the US. 
• From packing water to staying clear of animals, he shares how to avoid the worst mistakes he's seen.

For 37 years, Tom Haraden worked in nine national parks across the US.