Tortuguero is sometimes called "Nature's Venice." It is a maze of rivers, canals, lagoons, and tidal wetlands. The area gets 5,000 - 6,000 mm. (196 - 236 inches) of rain per year.
You can see from these photos why it is necessary to take a boat to float through the jungle to see wildlife, as it would be impossible to walk far amidst such wetlands.
It is very helpful to be escorted by a guide, as they are expert at seeing wildlife that you might miss, and they are very knowledgeable. Also, they know their way back after cruising around in the maze of waterways, which do not have street signs, of course, and leaving a trail of bread crumbs would not help one navigate your way back.
My wife asked our guide what was the most dangerous thing that has happened to him in the jungle. He said that once he was in an area of the waterways from which there was only one canal in and the same canal out. When it was time to head back at the end of the afternoon, a large tree had fallen across the canal completely blocking any passage.
He thought about whether he would have to spend the night in the jungle with a boat load of tourists. He probably would have been most afraid of the tourists. Fortunately, he was able to radio for help and the park rangers sent out another boat to retrieve everyone.
Happy St. Patrick's Day. What could be greener than the tropical vegetation of Tortuguero?