In the jungle, it's good to have a dog with you. Dogs chase away animals you really don't want to have to deal with, like snakes. Belize is home to a number of deadly snakes. The people who run the resort told us they've lost a number of dogs (and even a horse) to snakebites. But when a snake sees a dog, and feels the vibrations in the ground from horses and people, it will realize there's just too much to overcome and slither away.
Dogs also provide comic entertainment rolling around in the mud and diving into bushes chasing armedillos :-)
When they feel they are in danger, iguanas jump right out of the trees into the water. We were told by our guide that they have been known to land in the canoe, which is unfortunate for both the iguana and the occupants of the boat. If a frightened 3-4 foot lizard lands in your canoe, it will surely capsize. If you manage to escape without any scratches or bites, you can consider yourself lucky.
Don't go into the jungle without someone who knows where he's going. We had 2 guides, Juan and his son Jose, leading our horses. Juan talked, Jose translated. They carried machetes to keep the trails clear, ward off animals and slice fresh coconuts :-)
Juan and his family live in a house at the resort. They are immigrants from Guatemala.