Minecraft Crocs and Squawks

This idea is a little ambitious as it involves new mobs and changing some already well-established features, but I believe this would contribute so much to the environment of Minecraft.

1) Alligators could live in the rivers, potentially found in larger numbers around Mangrove Swamp biomes. They would be neutral to the player unless provoked, but potentially hostile to most other mobs such as sheep, cows, and horses that live on the land. To further this, certain passive animals (like the cow, sheep, and horse) that spawn near freshwater rivers/lakes might occasionally come close to water, dunking their heads in to drink. When they dip their heads, a lurking alligator might lunge at them and strike with their signature death roll.

2) Crocodiles live on coastal beaches. They are hostile to every mob (as in real nature they are highly aggressive), except for the final new mob I will introduce, the crane. 

3) Cranes live and make their nests in areas close to bodies of water. There is a specific phenomenon in nature called crocodile bird riding, where this specific species of bird rides on the back of crocodiles so as to keep their enemies close and visible. The crocodiles would love to snack on the cranes, but they are always unable to catch them in time! There are many fun interactions that could take place between these creatures.

Alas, I am running out of character space. Bird variants, unique drops, and tamable interactions are just some of ideas floating in my imagination!