Bought my 12 year old a hamster. The hamster got out of her habitrail. I took her to get another one because of all the extra things we had purchased. She chose a Teddy Bear hamster. A week later she found her original hamster. She put it in with the new hamster. The Teddy Bear hamster attacked the old hamster. Pulled a nice plug of hair out of her. Her Mom got her out. I then did some research as to why this happened. Research said never put any other hamster in the same cage as a Teddy Bear hamster. They said it would attack and possibly kill it. We should of been informed of this during our purchase. Especially since the sales girl was aware of the situation. This was a traumatic experience for my granddaughter. User's recommendation: Sales person should be better informed,so they can tell the customer.