Golden Hamsters in the wild are diurnal but in captivity are nocturnal. Do we know why?

in a previous article about Golden Hamsters, I wrote

After Rolf Gattermann’s death from cancer in 2006 at the age of 57, his team of collaborators, who had made Halle a centre of small rodent research, continued publishing their work and started new strands, including field work on the Golden Hamster in southern Turkey. One interesting paper, begun while Gattermann was still alive, reported that while in the laboratory male and female hamsters (whether derived from old line or from newly-caught individuals) are nocturnal, in the wild female hamsters are diurnal. They speculated that a balance in the environment whereby nocturnal predators (owls and foxes) are a more potent threat than diurnal ones (birds-of-prey and snakes) may be responsible.

Since then there have been a number of studies attempting to identify the stimuli which turn hamsters from diurnal in the wild to nocturnal in captivity. As far as I can see there has been no success. However, some smaller effects evoked by potential predators have been recorded. For example, hamsters exposed to the odour of domestic ferrets spent less time out of a simulated burrow. In another species, the pattern of activity was affected by the rodent community in which the hamster was living, the time out and about was shortened when there were aggressive gerbils around.

I wonder whether the nature of the housing has an effect, being reminded of the marked changes in thermoregulatory behaviour observed by Roger Avery, then in Bristol, and also by me, in lizards given different sorts of cage furnishings. The deep and dark burrow system in the wild is very different from the accommodation afforded to pet and laboratory hamsters. Sleeping quarters are not necessarily completely dark and the Golden Hamster in the wild is subject to a very different regime of light/dark periods to that in a cage. Some simple experiments could be done.

In the meantime we still do not know if the presence and perception of predators is responsible for the basic activity pattern in the wild of Golden Hamsters.

McPhee ME, Segal A, Johnston RE. 2010. Hamsters use predator odors as indirect cues of predation risk. Ethology 116, 517-523

McPhee ME, Ribbeck AE, Johnston RE. 2009. Male golden hamsters (Mesocricetus auratus) are more reactive than females to a visual predator cue. Journal of Ethology 27, 137-141

Scheibler E, Wollnik F, Brodbeck D, Hummel E, Yuan S, Zhang, F-S, Zhang X-D, Fu H-P, Wu X-D. 2013. Species composition and interspecific behavior affects activity pattern of free-living desert hamsters in the Alashan Desert. Journal of Mammalogy 94, 448-458. (Note—not on the Golden Hamster)