Penguin

Penguins are a type of NPC that appear in Cool, Cool Mountain and Snowman's Land. There are two type of penguins; big and small penguins.

Penguin Locations

Baby Penguins

There are two baby penguin in Super Mario 64. Both penguins are in Cool, Cool Mountain.

CCM Penguins
  The first penguin seen in the game can be found at the very beginning of Cool, Cool Mountain, atop the little hut.
This baby penguin's name is Tuxie. Bringing Tuxie to her mother rewards you with the star Li'l Penguin Lost.
  The second baby penguin is found near the Mother Penguin in Cool, Cool Mountain, atop the little hut at the bottom of the level.
Bringing this baby penguin to the mother penguin does not result in a star.

Big Penguins

Unlike the baby penguins, there are several more instances of larger penguins. Two of which are in Cool, Cool Mountain.

CCM Penguins
  The first of the bigger penguins is the Mother Penguin of Tuxie.
The Mother Penguin is found at the bottom of CCM, near the 2nd baby penguin, outside the lower hut.
 
 
Also in CCM is the 2nd big penguin, found within the slide portion of CCM, in the hut at the top of the mountain.
Once you complete the first star of CCM, Slip Slidin' Away, you can re-enter the slide and race this penguin.

Upon beating him in the race, you will be rewarded the Big Penguin Race star.
SL Penguins
  The final Big Penguin is in Snowman's Land, found partway up the snowman.
He aids you crossing in front of the snowman's face, blocking the snowman from blowing you back down to the bottom.

CCM infinite coins

The Mother Penguin may play a possibly important part in the CCM infinite coins route. Because the Mother Penguin gives a dialogue, Time Stop can be activated on the J 1.0 version of SM64. It is theorized that this penguin could play an integral role in performing the CCM infinite coins glitch. [expand on the route]