Sasquatch springs eternal.

While interest in aliens, ghosts and other, more Earthbound, ornery critters shifts in and out of vogue, America has a pretty constant big hunger for Bigfoot. The gargantuan galoot is the subject of beef jerky advertisements, popular works of fiction both on the page and screen, the namesake of several cannabis strains, and owner of possibly the most recognizable silhouette around (except the Bat Signal, of course).

The hairy hominid was also the subject of noted ecology author Robert Michael Pyle’s seminal work, “Where Bigfoot Walks: Crossing the Dark Divide.”

In the book, which was first published more than 20 years ago, Pyle chronicles his Guggenheim-funded investigation into the legends, science and subculture around Bigfoot.

He trekked into the unprotected wilds of the Dark Divide, near Mount Saint Helens, where he discovered both a giant fossil footprint and more recent tracks. He searched out Indians who told him of an outcast tribe who had not fully evolved into humans, attended Sasquatch Daze where he met scientists, hunters and others who have devoted their lives to the search, eventually realizing of the more ardent searchers: “These guys don’t want to find Bigfoot — they want to be Bigfoot!”

Now the surprisingly timely tome has been republished in a special, updated second edition, which includes the author’s own fresh experiences and findings in a new chapter that includes an evaluation of recent DNA evidence, the study of speech phonemes in the “Sierra Sounds” purported Bigfoot recordings, an examination of the impact of the popular Animal Planet series “Bigfoot Hunters,” the surprise reemergence of the famous Bob Gimlin (he of the infamous, yet-to-be debunked “Patterson-Gimlin film”) into the Bigfoot community, and more.

Pyle is the author of 14 books, including “Wintergreen,” which won the John Burroughs Medal. He’s also a Yale-trained ecologist and butterfly expert.

The author will visit Eagle Harbor Book Company at 7 p.m., Thursday, Aug. 31 to discuss the subject of Sasquatch, and the additions to this, his possibly most controversial book.

He opened up to the Review about Bigfoot, science, culture and writing — after having himself just come in from a recent lengthy walk in the woods (he’s trying to sight 70 species of butterfly in celebration of his 70th birthday).

*This transcript has been edited for length and clarity

BIR: Why does America love Bigfoot so much? What do you think the appeal is there?

RMP: First of all, we have to recognize that every culture has their giants and loves them. That part is not unique. You can look at practically any culture and discover giant stories that are close to their hearts.

Now, to go from that to the American Bigfoot, and why it seems to be so much beloved, three things come to mind.

The first one is that it’s had a great deal of publicity in the past half century, and that’s come from the Patterson-Gimlin film, from the tabloids, and from the movies. Not all that’s been positive by any means. Obviously, some of that’s been just turning it into a joke. But it has kept the profile high.

Number two would be the fact that Americans seem to have a fascination with wildness. That comes from manifest destiny and constantly pushing westward. And when you get to the edge of the West, where do you go? Well, you push into other forms of the wild, which might be outer space and UFOs and that sort of thing, it might be virtual reality and computer realms, it might be supernatural and the paranormal for some people. Or, for many people it is the actual deeper wilds, wilderness areas.

The third thing is, I think, a very important one, a very important distinction from most of the other giant stories, and that is that our giants might actually exist. I think that may be the most significant thing that makes Americans love their Bigfoot so much, the belief or the hope on the part of a lot of people, that, ‘Wow, this thing’s weird but it might actually be there.’

BIR: In another recent interview, the host made a point to highlight your many professional accomplishments up front, as if to emphasize your credentials before launching into the Bigfoot stuff. Do you often have to justify or defend your interest in this topic to your colleagues or other ecologists?

RMP: That’s a very good question. Not so much to my colleagues in the lepidoptera [the order of insects that includes butterflies and moths] science world. I’m pretty established there. I think most of my colleagues cut me some slack there. Some of them chuckle. I remember there was a Finnish lepidopterist who just shook his head when he saw me and he said, ‘You do good science, Bob, but I don’t understand why you’re monkeying with this stuff.’ So sometimes I do with other scientists.

I’ll tell you who I do have to justify it to, and that I get grief from, are my readers sometimes. Not most of them. Different people like different ones of my books the best, and it’s always fun for me to hear which book really struck their heart.

There are a certain group of my readers who are very, very resistant to [Bigfoot]. They say, ‘I read all your other books but I’ll never read that.’ Because they think it’s going to be stupid.

Maybe they think it’s going to impair their opinion of me or of my writing, or maybe it says something about themselves that they would lower themselves or that they would allow themselves to read what they would consider more a distraction.

Those people whose minds are locked tight on the subject — which are, I think, a minority — I do find that I have to spend some fairly tedious time if I care to talk with them and try to open up their mind a little bit.

BIR: Do you think that that resistance to a renowned nature writer like yourself tackling this subject comes from the idea that it may somehow dilute science? We’re living in a world of flat Earthers and anti-vaccination activists. Are the people who maybe ruffle a bit when they find out you’re writing about Bigfoot concerned for the preservation of “serious” knowledge?

RMP: Yes, in a word. Some of them are coming from that standpoint. I’m one of those people. I’ve lived a life of dealing with evolution deniers because I live in the rural countryside where there are a lot of Christian devouts, of many types, many of whom are fine with evolution but some are not.

That’s very similar to the epistemological problem that a lot of people have with Bigfoot. It’s just beyond the pale; it’s beyond their degree of tolerance. And, for that reason, yes, some of the people who are resisting are exactly that: They think that I’m living in a world of cognitive dissonance because on the one hand I espouse and perform science, peer-reviewed research, and on the other hand I’m writing seriously about Bigfoot.

BIR: Do you have a favorite cinematic portrayal of Bigfoot?

RMP: No. I don’t think a good Bigfoot movie has been made that I’ve seen. Some of the documentaries are pretty good. But, as far as the fictionalized accounts, the dramas, I don’t think so. “Harry and the Hendersons” is kind of fun. It’s an OK movie, it’s kind of like “The Goonies,” but it’s got nothing to do with Bigfoot really.

Of all the Bigfoot fiction that’s been written, there are two books that I think are very good. One of them is obviously Molly Gloss’ book, “Wild Life.” That’s a superb treatment of what life among Bigfoots might be. And I just read another one that I didn’t know about before that was pretty darn good, too. Bigfoot is only part of the story, but it’s near the end and it’s a pretty important part, and it’s very, very nicely imagined as a real animal. It’s a book called “Seven Rivers West.” It’s written by one of the most admired essayists in the country, a man by the name of Edward Hoagland.

BIR: In the book you sort of leave folks with the idea that belief in Bigfoot is a good thing, whether or not we ever have a definitive answer, if only because it might inspire curiosity about nature or an interest in conservation. Do you think Bigfoot is good for nature?

RMP: Yes I do. I think that an interest in the potential animal — I’m assuming the question is in the realm of Bigfoot as an animal, not in the realm of paranormal phenomena; I’m not putting that down, I just don’t have any interest in it — but Bigfoot as an animal, as a potential member of our fauna, our natural history, is definitely a good thing.

I think if people look at it that way, as maybe not even likely but a possible member of our planet, sure, it’s going to broaden their view of our full natural history and that can’t be bad. So I think it is good for nature, particularly if it helps with conservation.

I do have one agenda with this book. Well, I have two. One is I hope to entertain my readers, as always, and to open their minds to the world. But that’s true of all my books. The second one is that I hope this book helps to contribute to the conservation of wildness in the Dark Divide.

Frankly, one of the main reasons I would like the animal to be found, to be demonstrated in a way that’s accepted by the academy, [is] if that happens, one of the main reasons I would be glad for it — well, one is just to watch the fireworks, you know? In terms of science and religion and everything else. But the other practical reason is that it would presumably mandate strict protection of that area.