This mystery is another great one in the series by Gloria Skurzynski and her daughter. They're all set in the national parks and all have the same family in them, the Landons. The mother in the family is a veterinarian and the parks people call her in when there's a mystery they can't solve with animals in the park. I'm paticularly partial to this one because the mystery centers around wolverines!
When one of our nieces or nephews turns 13 we take them to a national park of their choice, and this summer we took Logan to Denali in Alsaka. That's where this story is set, so it was fun to read about a place where we were and to spot things on our visit that were mentioned in the story. The high suspense in this story made it a great read-aloud, too. There's a mystery about the animals but about one of the people in the story, too, so there's lots going on.
This book is available in the WOMS library. I definitely recommend it and the others in the series that are there.