[quote=Sloth]
Not the kind of animals you summon. If we had a size code, this is where I'd put in minuscule text: Except for the sharks and sea-creatures.I really don't see any major difference outside of your animal mimicry stuff. 
[/quote]

Summoning techniques do not have anything to do with the environment the ninja is in. You simply just learn the proper technique and summon the creature because I am pretty sure the rain village didn't have rhinos and yet the animal path could summon one.