Belly Up by Stuart Gibbs: Book Review, Age Recommendation & FunJungle Series Guide
If your child likes animals, mysteries, humor, and stories that move quickly, Belly Up by Stuart Gibbs is a great series starter to know about.
Belly Up introduces twelve-year-old Teddy Fitzroy, who lives around FunJungle—the enormous fictional zoo where his parents work. When Henry the Hippo, one of the zoo’s biggest attractions, suddenly dies, Teddy doesn’t believe the official explanation.
He thinks Henry was murdered.
That launches Teddy into an investigation filled with suspicious adults, animal facts, dangerous situations, and plenty of humor. More importantly, Belly Up is only the beginning of the FunJungle series, so kids who get hooked have plenty more Teddy Fitzroy mysteries waiting for them.
The publisher recommends Belly Up for ages 8–12 and grades 3–7, with a Lexile level of 820.
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What Is Belly Up About?
Teddy Fitzroy isn’t exactly an ordinary twelve-year-old.
His parents are scientists, and his unusual upbringing has given him plenty of experience around wild animals. Now his family is connected to FunJungle, a massive new zoo filled with everything from hippos to polar bears.
Then Henry the Hippo dies.
The adults at FunJungle say Henry died naturally, but Teddy notices things that don’t add up. He becomes convinced that somebody killed the hippo and starts trying to figure out why.
With help from Summer McCraken, the daughter of FunJungle’s owner, Teddy begins investigating the people who might have had a reason to want Henry dead.
And the closer they get to the truth, the more dangerous their investigation becomes.
Simon & Schuster describes Belly Up as the opening FunJungle mystery and identifies Teddy and Summer as the young sleuths investigating Henry’s suspicious death.
Belly Up Book Review
One of the things that makes Belly Up work so well for middle-grade readers is that it doesn’t feel like a book that’s trying to teach them something.
It’s a mystery first.
There are suspects, clues, danger, jokes, and plenty of reasons to keep turning the pages.
But woven throughout the story are interesting details about animals, zoos, scientific research, conservation, and animal welfare. Kids who already love animals will probably appreciate that part, while kids who simply came for the mystery may accidentally learn quite a bit along the way.
Teddy is also the kind of main character that works particularly well for this age group. Adults don’t always take him seriously, which means he frequently has to rely on curiosity, observation, and persistence to figure things out himself.
The result feels a little like a classic kid detective story dropped into the middle of a giant zoo.
What Kids Will Like About Belly Up
The biggest selling point is probably the combination of animals + mystery + humor.
There are enough animal facts to appeal to kids fascinated by wildlife, but the book isn’t written like nonfiction. Teddy is solving an actual mystery, getting himself into trouble, and encountering increasingly strange situations along the way.
It’s also funny without being aimed only at very young readers.
Common Sense Media similarly highlights the book’s action, humor, suspense, animal information, and mystery while noting positive themes involving scientific research, ethics, and humane treatment of animals.
For a reluctant reader who says, “I don’t know what I want to read,” this is exactly the type of book I’d consider trying.
What Age Is Belly Up Appropriate For?
The official publisher recommendation is ages 8–12, grades 3–7.
That seems like a useful general range, although reading maturity matters.
A confident 8- or 9-year-old who enjoys mysteries and isn’t bothered by discussions of dead animals may be perfectly comfortable with it. More sensitive children may prefer waiting a little longer.
Older elementary and middle-school readers are probably the sweet spot.
Is Belly Up Scary?
I wouldn’t classify Belly Up as a scary book, but there is some suspense and peril.
The entire mystery begins with the death of a hippo, and the book includes discussion of animal deaths and an autopsy. Teddy also finds himself in dangerous situations as the investigation develops.
For most mystery-loving middle-grade readers, it’s likely to feel exciting rather than frightening.
However, children who are particularly sensitive to animals being injured or dying may find some scenes more upsetting.
What Parents Should Know Before Their Child Reads Belly Up
This is one section I would definitely include because it’s useful for parents searching Google before buying the book.
The central mystery concerns the suspicious death of an animal, and there are descriptions involving animal deaths and an autopsy. There is also some mild peril, body-function humor and occasional mild language.
Common Sense Media additionally flags some dated humor, including jokes about weight and repeated use of an outdated term for a person with dwarfism. Its editorial recommendation is age 8+, while its user-submitted parent and child age recommendations trend somewhat higher.
Those elements don’t define the book, but they’re worth knowing about before handing it to a younger or particularly sensitive reader.
On the positive side, the story strongly emphasizes curiosity, scientific thinking, animal welfare, research, ethics, and persistence.
Is Belly Up the First FunJungle Book?
Yes. Belly Up is the first book in Stuart Gibbs’s FunJungle series.
As of 2026, there are 10 published FunJungle novels, with Ape Escape being the newest. Stuart Gibbs has also announced that an eleventh FunJungle book is planned for spring 2027.
FunJungle Books in Order
- Belly Up
- Poached
- Big Game
- Panda-monium
- Lion Down
- Tyrannosaurus Wrecks
- Bear Bottom
- Whale Done
- All Ears
- Ape Escape
The publisher currently lists Ape Escape as the tenth FunJungle novel.
That makes Belly Up an especially nice choice if you’re looking for a book that could turn into a longer reading obsession rather than a one-and-done story.
Do You Need to Read the FunJungle Books in Order?
I would.
Each book contains its own central mystery, but Teddy and the other characters continue developing throughout the series.
Starting with Belly Up means your child gets introduced to Teddy, Summer, FunJungle, and the relationships between the characters exactly as Stuart Gibbs intended.
And if your child likes Belly Up, you don’t have to hunt around for what to read next—Poached is waiting.
Who Would Enjoy Belly Up?
I’d particularly recommend it for kids who like animal stories, detective mysteries, funny adventure books, zoos and wildlife, science, or other Stuart Gibbs series such as Spy School.
It’s also a potentially good choice for kids moving beyond shorter chapter books but who still want something fast-moving and entertaining.
Simon & Schuster lists the paperback at 320 pages, but the mystery-driven structure makes it feel much less intimidating than a slower 300-page novel might.
Is Belly Up Worth Reading?
For kids in the middle-grade range who like mysteries and animals, Belly Up has a lot going for it.
There’s a genuine mystery to solve, a funny and capable kid protagonist, plenty of action, interesting animal information, and an entire series to continue afterward.
I especially like books that can lead kids into reading more books, and this is where Belly Up has a major advantage.
If Teddy Fitzroy and FunJungle click with your child, there are nine more published adventures to move straight into.
Buy Belly Up on Amazon | Buy Belly Up at Bookshop.org
Final Thoughts
Belly Up is a clever combination of animal adventure and kid detective story.
The premise is unusual enough to grab attention—a twelve-year-old investigating the murder of a hippopotamus—but underneath the humor and mystery are genuinely interesting ideas about animals, science, ethics, and figuring out the truth for yourself.
For families looking for a funny middle-grade mystery series with lots of books available, Belly Up is a very good place to start.
