Just curious of the purpose and what causes it and makes it happen
In: Biology
The exact cause is due to blood vessel restriction from a signal from your autonomic nervous system.
As mentioned in another post, this can increase grippiness in wet environments.
It should be noticed that it can also be caused by nerve damage.
To increase grippiness. The wrinkles give you more points of contact with an item you are trying to hold or manipulate. Which comes in handy if your hands are wet