Into the Wild: Chapter 18 Summary

Instructor: Joelle Brummitt-Yale

Joelle has taught middle school Language Arts and college academic writing. She has a master's degree in education.

In this lesson, we explore Chapter 18 of ''Into the Wild'', focusing on the author's various theories about the causes of Chris McCandless's death and descriptions of his journal entries from the last weeks of his life.


So what really was responsible for the famous Chris McCandless's death? We may never know for sure, but Krakauer has some ideas.

Chapter 18 of Into the Wild brings to a close Jon Krakauer's narrative on Chris McCandless's journey from an affluent young man living in Maryland to an Alaskan wilderness wanderer. In the previous two chapters, the author traces McCandless's travels deep into the Denali National Park reflecting on what Chris may have been experiencing or thinking as he attempted to live in an isolated and unfamiliar setting.

At this point in the book, Krakauer has walked the Stampede Trail crossing the Teklanika River and has spent time at the abandoned bus Chris made his home for 112 days.

Cause of Death: Potato Seeds...Or Was it?

Wild Potato Plant
Wild Potato Plant

As Krakauer wraps up his account of Chris McCandless, he attempts to pinpoint exactly what led to the young man's death. He begins the chapter by drawing on an entry from McCandless's journal dated July 30th. In this entry, Chris writes, 'EXTREMELY WEAK. FAULT OF POT. SEEDS.'

The author first assumes that this entry refers to Chris eating the seeds of the wild potato plant. He posits that McCandless may have collected what seemed to be the seeds of the wild potato plant, but may have actually gathered and eaten seeds from a plant that looks remarkably similar, the wild sweet pea plant. The pea plant contains toxins, whereas the wild potato plant is edible.

While Krakauer poses this idea, he quickly discounts it by saying that according to his journals, McCandless had previously correctly identified the wild potato plant so it would be unlikely that he would suddenly mistake the wild sweet pea for it.

Though he sets aside this initial theory, Krakauer does wonder if the wild potato seeds may contain _alkaloids, a natural substance which can produce 'powerful pharmaceutical effects on humans and animals.' He continues theorizing that the seeds are likely to have concentrated amounts of alkaloids to deter wild animals from eating the seeds. However, this idea is laid to rest when Krakauer sends the seeds to a laboratory to be tested and discovers that they show no signs of alkaloids (in earlier editions of the book, this information was not known, and Krakauer still speculated that it was the seeds. Later editions show he changed his theory to mold, which we will now discuss).

Maybe It Was the Mold

With the seeds themselves not fitting the bill for the cause of Chris McCandless's death, Krakauer turns instead to another idea. Because McCandless seemed so sure about the wild potato seeds causing his weakness, Krakauer wonders if something on the seeds, perhaps toxic mold, might have poisoned the young man.

During the period when McCandless was collecting seeds, the weather was particularly rainy. Chris stored the seeds he collected and ate in plastic bags. Krakauer wonders if they may have grown a mold that contains _swainsonine, an alkaloid that has been known to kill livestock. He proposes that McCandless may have eaten so many seeds that a high concentration of swainsonine built up in his body causing weakness that prevented him from being able to hunt and feed himself.

The Downward Spiral

Though it is not clear what caused Chris McCandless's death, by August 5th, the 100th day of his time in the wilderness, the adventurer was weak and recognized that death was not far away. The irony of this, according to Krakauer, is that there were three national park-owned cabins that were not that far from the abandoned bus where Chris might have found food and shelter.

However, as it turns out, the cabins had been raiding and vandalized, exposing and destroying the food within (there is some speculation that Chris himself caused the damage months earlier, but no evidence. The national park service does not suspect him).

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account