I visited Belize in 1989 and spent a night at the Bermudan Landing Howler Monkey Sanctuary. A great little place, set up to protect the Guatemalan Black HowlerMonkeys that were easily seen. Also saw what I guess were Proboscis Bats, roosting on a tree stump at the edge of the river. At other times of year, the villagers told me that Tapirs, Peccaries and even Jaguars are around.
Also saw what was probably a Bottlenose Dolphin en route to Caye Caulker.