Sneaking is an action performed by holding down the "Creep (Sneak Quietly)" action, by default CtrlPC 
PS 
Xbox/Switch 
Joy-Con.
Sneaking allows a Super Animal to make less noise and have a better 
Gun stability at the cost of slower movement speed.
Super Powerups like the 
Claw Boots and the 
Ninja Booties benefit from sneaking. Sneaking with the Claw Boots will reduce the amount of noise made by a player's movement[verify]. Since the noise a player makes while having the claw boots equipped is increased, this helps them to reduce the amount of noise they make while having them equipped. Similarly with the ninja booties equipped and sneaking toggled, an enemy player would be very hard to hear from another players perspective.
Super Creep Roll
The Super Animal can sneak in tandem with a Super Jump Roll (executed with Space) to perform a quieter but slower dodge roll.
Sniper, Rifle and Dartfly Zoom-out
Sneaking while having a 
Sniper, 
Hunting Rifle or 
Dogna's Dartfly Gun equipped provides an additional 15% zoom out (Sniper) and 10% zoom out (Hunting Rifle and Dogna's Dartfly Gun), which allows players to see further and helps with precise, long-range shots.