- Who
- Roborovski Hamster
- What
- 4–5 centimetre(s)
- Where
- United Kingdom ()
- When
The world's smallest breed of domestic hamster is the Roborovski hamster (<em>Phodopus roborovskii</em>) which typically grows to a length of 4–5 cm (1.5–2 in). These hamsters originate from Mongolia and northern China.