due to rio's tropical climate it is also a good idea to take some insect repellant, and some sunscreen, even a sun-protecting hat, depending on the hike.

also particularly advisable is to have a local cell phone, so that in case of need help can be called easily by dialing local numbers - pre-charged pay-by-minute phones can be usually rented or received for free via guides or via the accommodations' providers. 

last but not least, an old-fashioned paper mapof the area should be brought along, easy to find online or at a bookstore.

needless to say, smoking and consuming alcoholic beverages in a forest can endanger everyone in a group, and it is usually forbidden in all parks by any legitimate guide.