The bears of Katmai National Park and Preserve in Alaska are gorging on salmon and packing on the pounds ahead of the long winter. With the days growing shorter, it means that the annual Fat Bear Week tournament is just around the corner.

A new children’s book, Big Fat Bear Battle!, celebrates the famous bears. Written by Alaskan author Brooke Hartman and illustrated by Can Tugrul, the book follows reporters Goldie Fox and Moose McMahon, as they cover a wild competition between Alaska’s biggest brown bears as if it were a wrestling tournament. 

Popular Science recently spoke with Hartman about her new book and all things fat bears. Answers have been condensed for clarity. 

Laura Baisas: Tell me a bit about your experience with Katmai’s bears.

Brooke Hartman: My family goes to Katmai every single summer. We’ve been going out there now for over 20 years. We have a cabin out in King Salmon, a little town that you can commercially fly into. [sic] These fish that are coming from the Naknek River and other rivers up there just congregate at this lake at the bottom of Brooks Falls. They have this genetic drive to come up here to spawn. So the bears are just stacked trying to get these fish. And their goal is to be as fat as possible. They’re like little sumo wrestlers.

LB: What keeps you coming back year after year?

BH: No two years have ever been the same. Every year is different somehow, or something happens when we’re out there. Last year we had an insane amount of fish. It was absolutely bizarre. It looked like you could just walk on the backs of them across the water. 

One year, a young bear was infatuated with my daughter and followed her. I think it just saw that she was this young person and was like, “Hey, we can be buddies.” And we ended up having to go into one of the outhouses and hide, even though we did the backing up thing and gave it plenty of space.

We saw a wolf once that would hang out by the water. It would snatch the leftover fish from the bears. A lot of people don’t realize that by the time the bears have been at Brooks Falls for a while, they are so gorged on fish that they only eat the bellies and the brains. They then toss the rest of the fish away, and it’s the part that you and I would eat. So the river is swarming with these carcasses of fish, that would be like a fresh filet to us.

LB: How did you get the idea for this book?

BH: The format that jumped out at me was this sort of like a wrestling match. Almost like a “let’s get ready to grumble,” feel and the Bears having wrestling names, like a WWE sort of tournament. So I wanted it to be a very punny, very funny, very engaging, interactive kind of book, so that kids who are visiting Brooks Falls, or parents, grandparents, relatives visiting Brooks Falls, can bring a little bit of that feel back with them. It brings some of that battle vibe into it in a fun way, that’s not quite as gruesome as it sometimes gets.

LB: What was the biggest challenge when writing this book?

BH: I would say trying to balance the fun and the whimsy and the punny like comedy of it with the facts. With the illustrations, we went back and forth a lot, since I had a bit of a hard time with the clothes at first. I was like, “Can we pare this down? Because there’s no Gap or Old Navy in Bristol Bay.” We ended up meeting in the middle, so they have some clothes on, but not [sic] like a full dress and shoes and socks.

LB: Why do you think that these bears have become so popular?

BH: I just think that this idea of these bears congregating at this one place every year to duke it out for salmon and to get super fat is great. We as a society have become sort of obsessed with weight in this weird kind of dysfunctional way, yet here is nature saying, these animals need to embrace it. They have to eat, otherwise they don’t survive. So it’s just this healthy way for us to embrace these fat bears. I think it’s super fun, engaging, and brings people together over a really fun topic.

And they can be relatable. One year when my kids were fairly young, I remember seeing a mother bear trying to sleep, and her cubs were playing and wrestling and growling. And the mother bear was like, “I don’t have any more energy for you guys right now.” [sic] I could relate to that bear!

LB: I know that this may be like picking a favorite child, but do you have a favorite bear?

BH: Oh gosh, you know, I have never had a favorite bear from year to year. I do think it’s funny and great when the female bears end up being like the biggest bears. I’m going to be rooting for them, like “You go, girl, you get that salmon!” So my favorite is when female bears end up being the biggest.

Big Fat Bear Battle! is published by Little Bigfoot, an imprint of Blue Star Press, and distributed by Penguin Random House. It will be available wherever books are sold on August 25.