When you first get your hamster home, take some time to make the room where it is kept escape proof. Gaps in the wall etc should be filled. Electrical cables should be out of reach as a hamster can gnaw through these. Remember hamsters can climb up curtains and escape out of open windows (Adby& Neill 2004).
Some lucky people have just put out the hamster cage and their animal has climbed back in. But a missing hamster is more likely just to move all the bedding out of the cage to make his new home more comfortable. So try putting some hamster food in something like a big mixing bowl. Set up either a hamster ladder or a pile of books, so that the hamster can climb up to the side. Then with luck it will fall into the bowl and will be unable to get out.
A hamster owner once told me: “When our neighbour’s hamster took up residence in the cavity wall, my husband threaded a peanut with a few inches of fishing line, knotted securely, with the other end tied to the middle of a matchstick with the head cut off. The stick was used to prop up a plastic bowl and the peanut was pushed under the bowl with some other food. We went to bed but about ten minutes later heard a bumping noise. We retrieved the hamster from under the bowl, and the stick and peanut from its mouth. A transparent bowl would probably make it a bit easier to catch the hamster.”
Put out water in the room where your hamster used to live. Otherwise he may die of thirst. Keep the family cat or dog out of the room.
Adby, S., & Neill, D. O, (2004), Hamsters in Sickness and in Health, Milverton, UK, Capall Bann Publishing.