How does the running wheel affect the behaviour and reproduction of golden hamsters kept as pets?

In order to compare the physical condition of the females, they were regularly mated and raised up to four litters before they stopped reproducing. Body masses did not differ between the groups, but females with functional wheels had significantly larger litters. Offspring growth did not differ, probably because the females decreased running in the wheel during pregnancy and stopped running completely during lactation. Therefore, we conclude that a large well-constructed running wheel will have no detrimental effect on golden hamsters kept in large and enriched cages with ad libitum access to adequate food and water. On the contrary, the running wheel may have had a beneficial effect on the well-being of the hamsters since it significantly decreased stereotypic bar-mouthing.