I don't feel qualified to say what's typical, but I went into parenting with some vague understanding that toddlers would do things like call all four-legged animals 'dog' or 'horse' and not be able to differentiate all the animals for quite some time, but mine were way ahead on that (as well as things like naming colors and counting). My DS was also very particular about using the specific name for a species of dinosaur or other animal, insect, critter, etc. Enjoy learning all the stuff you never knew! :-)
