In my opinion the best wildlife photographer in the world as of now is Micheal Aw.
Michael AW is well known for his saturated color imagery and best wildlife photography.
There are some other great wildlife photographers that could be even better in other peoples opinions such as Marina Cano, Shannon Wild, Ellen Cuylaerts, Julius Kramer, Emanuele Biggi and Peter Chadwick.
I almost forgot there's also a few other good wildlife photographers besides the above such as Connor Stefanison, Annette Bonnier and Jess Findlay.