Is there puma risk?
The chance of attack by puma (similar to the North American cougar) is miniscule.
The chance to see a puma is miniscule, unfortunately.
We have heard of no encounters on Santa Cruz.
If you are approached by a puma, be aggressive making noise & waving your arms. If attacked, fight back as if your life depends on it. It does.
Storing food safely
At night you should cache food out of reach of animals. On most Andean hikes dogs are the concern but on Santa Cruz it is cows that are the biggest mooches. We keep food in the tent, but sealed in air tight kayak bags.
Herd animals including horses have been known to damage tents trying to get at food, especially salty food. Alberto (Pony Expeditions) in Caraz first alerted us to this danger.
Are there any dangerous snakes?
None we are aware of.