Penguin

The penguin is a villager species that has appeared in every game of the series. They are defined by orange bills and their chubby appearance.

Their was only one new penguin introduced in Animal Crossing: City Folk.
There are five penguins that have made appearances in all of the Animal Crossing games.
The majority of penguins who have picture inscriptions revolve around being "cool" like ice, where penguins live.

Name	Games	Birthday	Picture Inscription
Aurora	Animal Crossing Animal Crossing: Wild World Animal Crossing: City Folk	January 27th	"Just keep your cool."
Boomer	Animal Crossing Animal Crossing: City Folk	February 7th	N/A
Cube	Animal Crossing Animal Crossing: Wild World Animal Crossing: City Folk	January 29th	"Stay cool."
Friga	Animal Crossing: Wild World Animal Crossing: City Folk	October 16th	"This isn't a fortune cookie, It's an important life lesson!"
Gwen	Animal Crossing Animal Crossing: Wild World Animal Crossing: City Folk	January 23rd	"I'm just that cool."
Hopper	Animal Crossing Animal Crossing: Wild World Animal Crossing: City Folk	April 6th	"This is my good side."
Iggly	Animal Crossing: City Folk	November 2nd	N/A
Puck	Animal Crossing Animal Crossing: City Folk	February 21st	N/A
Roald	Animal Crossing Animal Crossing: Wild World Animal Crossing: City Folk	January 5th	"I'm not waddling! I'm working my glutes!"
Analogue	Animal Forest e+	N/A	N/A
Nobuo	Animal Forest e+	N/A	N/A
Kamaboko	Animal Forest e+	N/A	N/A