Oda compared some chartacters to certain animals in new data book
if you know Oda he won't do anything "randomly"
I did a simple researcha and here's the result
Roger : The Quokka - The Laugh Bringer
The Quokka spirit animal teaches us to show and appreciate joy and laughter. A true spiritual healer the Quokka spreads light and love where there previously was none. Guiding one to find the happiness that is embedded in us all. The quokka opens our soul and reflects this directly at us through the quokka smile.
Shanks : Lion - The Guardian
In Asia, the lion was popularly believed to have the power to repel evil, and for this reason it was habitually used to guard gates and doors
Teach : Hippo - Dreams
The Hippo Totem speaks of your dreams and how you achieve them
Sticking to an Earth-Water balance is part of Hippo's daily life, so finding a balance between being grounded or practical and reaching for your loftiest of dreams is paramount.
Whitebeard : White Whale - Can not be defeated
It has been suggested that the White Whale symbolizes God, who should be respected and left alone; nature and the quest of men to prove their dominance over it; and the Biblical Leviathan, a large sea creature who cannot be defeated, as well as other ideas.
Buggy : Panda - Luck
Eastern cultures regard Panda as a symbol of peace and luck. When Panda appears, you may find your entire outlook on life becoming brighter
Koby : dolphin - savior of sailors
The dolphin is associated with both water and air elements, living in both realms, symbolizing both the emotional and intellectual traits. The dolphin is a symbol of protection for its presence in stories about saving the drowning sailors or other humans in distress
p.s
Marco and Phoenix was there but connection is more than obvious
calling