Makazine,
North or south, don't have too many worries. I'm regularly in north and south with family and friends, with locals and non-locals and I've not experienced any problems.
Some people are sensitive to the use of different words - TRNC, Greek and so on - but this is where being a non-native might help : just say you're confused as to what the right phrase to use is, what words the person you're just talking to uses. Nine times out of ten, people are fairly relaxed and forgiving about it and the other times the usually say "don't use X phrase".
As far as student population is concerned, my impression is that the universities in the north are probably more diverse than the south, with students from across Africa, Middle East, Central Asia, Eastern Europe as well as Turkey and northern Cyprus. There is a range of origins for students in the south but my impression and it is only an impression is that it is not quite so diverse. Equally I beleive that the main language of instruction in all (?) (most ?) Cyprus universities, north and south, is English.
Crossing between south and north is no problem for US citizens. I'd encourage you to do so, the more interaction and learning the better. Igorance is the enemy of trust and the friend of fear. Being a student - especially an exchange/visiting student - is about overcoming ignorance. The US embassy has a number of initiatives, including educational projects, encouraging collaboration and exchange between ordinary folks - what they like to call 'civil society' projects - north and south.
The snakes question : good to have the opportunity to discuss the amazing fauna (and flora) of Cyprus ! There are a few species of snake in Cyprus - about ten or eleven. These are :
the Western whip snake; large whip snake; leopard snake, ladder snake, grass snake, smooth snake, southern smooth snake, Montpelier snake, asp viper, nose-horned viper and the slow worm.
The only venomous ones - that is, of worry to human beings - are, I believe, the two vipers listed. However, the habitat of all of these snakes has been seriously encroached and their numbers are declining and so are now largely restricted (as you'd expect) to rural, agricultural and mountain environments. If you go marching through the maquis countryside especially in breeding season you may inadvertently disturb them in which case they may become aggressive. Otherwise, the old adage applies, if you don't threaten them, they won't threaten you. Having said all that, Cyprus snakes are kids' play compared with Texan snakes.
all the best