Digging is an ability Pikmin have in most Pikmin games. Pikmin can both dig out something in the ground, or dig their way in some holes.
Digging out objects
Some objects may be partially or completely buried under the ground, and before they can be carried, they must first be completely unearthed by using the Pikmin. The more Pikmin digging out an object at once, the faster it is dug.
In Pikmin 2, treasure that is completely underground does not have any obvious indicator of its presence. Only White Pikmin have the ability to detect this type of treasure, and when they're told to work on the spot the collectible is at, they will begin slowly digging it out until it peaks to the surface, at which point other types of Pikmin may help. The only way a player has to tell that there's treasure in that location is with the Treasure Gauge, or by having White Pikmin scan the floor with the group move mechanic. It should be noted that in this game, White Pikmin automatically start digging a buried item (whether it is partially or completely buried) without the player's consent; this does not apply to other Pikmin types.
In Pikmin 3, all Pikmin types can unearth objects at any depth, removing the White Pikmin's exclusive digging ability. Yellow Pikmin have been given an extra trait, though, in that they can dig out objects faster than other types besides Rock Pikmin which dig at the same speed. Interestingly, data files say that Yellow Pikmin are the best diggers, but don't say anything about Rock Pikmin. Also in this game, bomb rock explosions can help dig out buried items, but they don't affect spacesuit upgrades. Flukeweeds can also be used to pull out objects under the ground, but that does not involve the digging ability Pikmin possess.
In Hey! Pikmin, a small number of treasures are found partially buried, and need to be dug out before Olimar can collect them. The Pikmin can also dig out some special objects, like a pipe that gets used as a ramp in Below the Ice. They can also dig buried Sparklium Seeds.
Digging into holes
In Pikmin 3, there are two hole obstacles that Pikmin can dig their way through. Dirt mounds are entrances to underground burrows that contain items and tunnels are pathways covered in rubble that can be dug out to allow passage.
List of buried objects
In Pikmin 2, whether a treasure is buried or partially buried is actually a property of the treasure itself and not its locations; the treasure will always have this trait no matter where it is generated. That is not the case in Pikmin 3.
Fully buried treasures
In Pikmin 2, these treasures are always fully buried and require White Pikmin to obtain:
Partially buried treasures
The following treasures are always partially buried and can have any Pikmin obtain them:
Pikmin 3 buried objects
In story mode, fruits and pellets are always partially buried while spacesuit upgrades are always fully buried and create a lump in the ground where they are located. In Mission Mode, fruits can be fully buried and create a lump in the ground as well. The following lists details the buried objects the player can find in Story Mode and Mission Mode: unless otherwise specified, the approximate times taken to dig out each object are obtained using one Blue Pikmin, the most "normal" Pikmin type.
Garden of Hope
Silver Lake Remix
Thirsty Desert Remix
Hey! Pikmin buried treasures
In Hey! Pikmin, buried treasures aren't completely underground, and are always visible.
Different Pikmin types have different speeds for digging. The exact speeds cannot be determined, but they seem to reflect the Pikmin's attack power, with the exception being Yellow Pikmin in Pikmin 3, which were made to be better at digging out buried objects on purpose. The following table lists relative digging speeds for unearthing an object, based on the most "normal" Pikmin type, the Blue Pikmin. Speeds for digging a tunnel or digging a dirt mound are a bit different.
When under the effect of the ultra-spicy spray, every Pikmin will dig out an object at the same speed as an unsprayed Purple Pikmin in Pikmin 2, and an unsprayed Yellow Pikmin in Pikmin 3. This change also happens to Purple Pikmin and to Yellow Pikmin, respectively. The maturity of a Pikmin does not have any impact on its digging speed.
In Pikmin 3, the time taken to dig out depends on the object itself: while it seems constant for those partially buried, it's slightly random for the fully buried ones. This is a matter of few seconds for the fastest Pikmin, and a matter of few minutes for the slowest Pikmin (Winged and White Pikmin).
In Pikmin 2, a buried object is in a special state with a certain amount of health, and Pikmin digging it out actually attack it, causing its health to drop, and its appearance to look more and more expose. A totally buried treasure has 5850 HP, and a partially buried one has 5150 HP. Non-White Pikmin can join in when a treasure's HP reaches 5150, as a result. A specific sound plays when this health is at 1170, 2340, and 3510.