SOLVED. Childrens book: young boy gets trapped in a strange and mysterious world. [s]

[Gabe]

Children's fantasy 10 years old at least. 2000-2010. I got it from a library and it was an audiobook CD set if that helps.
At the start of the book, a young boy goes out canoeing and gets lost in a rainstorm.
He falls over a waterfall and is transported into a strange and mysterious world.
He walks and finds a steampunk rhinoceros in the desert. Later on, the rhinoceros gets into a fight with an anaconda and sacrifices itself to save the boy. The boy journeys into the jungle and gets captured by a tribe of monkeys.
They keep him as a pet but the kid wants to escape, so
he has to beat monkey in arm wrestling.
The only way he can win is by tricking the monkey leader into eating a sour candy to make him lose the game.
The kid escapes and launched into a pirate world.

[Ayshe]

Charlie Small 1: Gorilla City maybe?

[Gabe]

Ayshe wrote: " Charlie Small 1: Gorilla City maybe?"
Yes! Thank you!