Ok thats a bit clearer then I would go for the storage cards then they will outlast the conditions your camera will be able to manage and keep them safe in a good waterproof bag I think a rucksack would be asking for trouble if you get wet or fall into a river etc.. In humid conditions also use a plastic bag to use when you take the camera out..  Rainforest means just that it rains and you will get soaked... Be aware that batteries will not  last half the time in cold conditions so keep them warm on your person..

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt