Gerbils are desert creatures, and so over time they have evolved an extremely strong burrowing instinct. In the wild, they would need to create intricate tunnel networks in order to escape the heat of the day and to avoid all the predators who are out searching for them. Although some gerbils create more intricate and extensive networks than others, all of these little creatures will love running around in tunnels. It makes them feel safe and secure.
Gerbils love tunnels - they build such structures in order to escape from heat and predators
Gerbil tunnels can be provided in addition to their bedding - ready-made tunnels should always be supplied as well as bedding, rather than instead of. Although gerbils will love their tunnel they need to be able to satisfy their instincts to create their own as well.