I was wondering about this because Hannibal and his Army were way back in Italy terrorizing the Romans at Cannae and Trasimene, etc. but surely there must be some communication between Hannibal and the Carthaginian Senate, as evidenced from him being called back to defend Carthage at the end of the Second Punic War. How did these messengers travel the dangerous lands without taking the mountain pass through the Alps and surely dying? How did the Carthaginians ensure their safety? How often was Hannibal contacted by Carthage during the war?
Bonus: when would the Carthaginian have heard of the great victories over Rome in Cannae and Trasimene, and Scipio Africanus' victory over Hannibal at Zama
The messengers surely would use boats. Hannibal at that time was running around in the south of Italy. Pretty sure he had his base at Brundisium or around there. At that time Carthage still had a big navy so getting them across wouldn't be that hard I think. Trasimene is in the north but again he had access to cities with harbors afaik. I have no idea how long it took to get from south/north Italy to Carthage by boat though, a few weeks maybe? Zama was about a 100 miles from Carthage so I'm guessing a few days. Scipio Africanus by Basil Liddell Hart is a great book on the subject.