Even the smallest of hamsters have lipocalins in their urine.

Turton MJ, Robertson DH, Smith JR, Hurst JL, Beynon RJ. Roborovskin, a Lipocalin in the Urine of the Roborovski Hamster, Phodopus roborovskii. Chem Senses. 2010 Jun 24. [PUBMED][PDF] [Abstract...]