everyone has heard the question "whats the difference?" but i'm asking why. if they inhabit the same places, eat the same things, behave very similar then why do they look different? why did crocodiles evolve with sensory pits and alligators didn't? why do crocodiles have a pointier snout? how come when an alligator closes it's mouth you cant barely see it's teeth but a crocs are plainly visible? why did "mother nature" if you will, make them different at all?
sorry I worded the sensory pit thing wrong gimmenam... I did mean why crocks have them down their whole body where as alligators only have them on their jaw : )

Why not? There are 4 crocodilians, and all have basic differences. There are several species of each basic type and each species has different characteristics. Why not?

Actually, alligators ~do~ have sensory pits, it's just that theirs are only on their jaws and snout rather than down their entire body.

Millions of years ago, there were even more variations on the theme, including herbivorous species...

The longer pointier snout is easier to catch fish with, look at the gavial, it's diet is strictly fish, and it has the narrowest, most slender snout of them all...

Alligators, while they ~like~ fish, don't get me wrong, their diet in many areas consists of more land-based prey in a good deal of their range.

I'd be willing to venture a guess that waaaay back in the day when the species split, there was a big rift in dietary preference, with what eventually became crocodiles eating more aquatic prey, (not saying they wouldn't take down any land animals silly enough to drink from their water hole), and what eventually became alligators focusing a bit more on ambushing land animals that would come to drink... I think this would also explain why crocs have more sensory pits than alligators... if a baby gator is able to feel one drop of water hit 100 gallons, what is it for crocs with that many more pits?

They have been different species for a very very very long time, and while we can only guess, I'm sure there was some niche that the alligator design filled a little better than the crocodile design did, and vice versa.

It is true that crocs and alligators are very similar. That is due to common ancestry and also due to living in the same environment and making a similar living. There are differences between them though, as crocodiles tend to live closer to marine environments than alligators. Crocodiles are also larger. Their differences may be explained by their reproductive isolaton, chance and adaptations to their slightly different ways of life. Sometimes living a similar way of life in a similar environment is not enough for two different species to evolve exactly the same features because mutations depend on chance. No animal can order a mutation just because it is needed. If a mutation never arises in a croc but it arises in an alligator or vice versa, then that is the reason they are different. Because they don't interbreed, they don't share innovations. Innovations that arise in one species will not be shared with another. That is the biological way differences are maintained in different species.