What is the difference between a Crocodile and an Alligator?

 
 

What is the difference between a crocodile and an alligator?
Last weekend I took this image of a crocodile and thought I may as well do something with it, so it’s on the web. Made me think about the physical differences between alligators and crocodiles.
First things first, not all the articles I read up on agree on many aspects, but not on all, even the basic differences, so beware, and double check if you are doing serious research.
The crocodile above has teeth sticking out everywhere. One of the main differences quoted is that when a croc has his mouth shut both upper and lower teeth are visible. Now I know this image is of a croc and there are enough teeth to be seen, therefore this is a croc. An alligator is different in that when the animal’s mouth is closed only the upper teeth or no teeth are visible.
Rule Number 1: If the reptile in question has its mouth closed and you can see upper and lower jaw teeth, it is a crocodile.
The second major difference has to do with the size. Crocodiles are larger and heavier. How much larger and how much heavier?
There are always exceptions to the rule but general consensus is that crocs can grow to about 19 to 20 feet and an alligator to between 14 and 15 feet.
The heavier part? Could not find an answer
Rule number 2: Crocodiles are larger and heavier than alligators. Which is of theoretical value unless you seen them together or have a tape measure with an accommodating animal.
Another major difference is the size and shape of the snout.
Alligators have broad noses as in “U” shaped whereas crocodiles have pointed sharp noses. One needs to see two images for comparison purposes to get this into perspective. Why the difference? Alligators have a greater crushing ability to break hard food like turtles, and crocs eater softer food such as fish and smaller land animals that are “ambushed” while drinking. Again this is rule of thumb and there are exceptions, crocs are known to bring down a Gnu, which cannot be considered small
Rule number 3: Alligators have shorter and broader heads with flat and wide snouts compared to crocodiles that have longer heads with pointed snouts.
Color.
Alligators are darker in colour and appear to be black when wet, whereas crocodiles are lighter in color as in gray. The image above is what one could expect from a croc out of water
Rule number 4: Aligators are darker in colour than crocodiles
By the way, according to one source, the collective noun for a bunch of crocodiles is a “bask of crocodiles”. I did not cross check this and present it at face value