Prof. Dr. Annika Herwig

Research interests: 

The main focus of our research is to understand the regulatory  mechanisms underlying seasonal adaptations in small mammals. Mammals living in a seasonally changing world face energetic bottlenecks during winter, when ambient temperatures are low and food sources are scarce. To overcome these, seasonal mammals show extreme morphological and physiological adaptations to maintain energy balance.
Currently we work on Djungarian hamsters that precisely adjust fur properties, reproduction, body mass and metabolism to the time of year. Remarkable is the pronounced and precise annual body weight cycle of this species that is controlled by photoperiod and occurs despite ad libitum feeding. Another extreme adaptation of Djungarian hamsters to energy shortage in winter is the expression of daily torpor. During torpor, metabolic rate is downregulated and body temperature drops to values between 15-25°C - striking state for an endothermic mammal!
Combining in vivo biochemical and molecular methods, we aim to identify how the brain regulates these profound adjustments of energy balance and metabolism. The underlying regulatory mechanisms in the brain are of great interest since they are able to control body weight and metabolism very precisely in the long-term and over an extreme range. Undertanding them is of great interest for basic physiology research as well as for applied biomedical projects.


Djungarian hamster (Phodopus sungorus)
Djungarian hamster
Portrait Annika Herwig


Lab Members:

Dr. Victoria Diedrich
Elena Haugg (PhD candidate)
Daniel Höfer (PhD candidate)
Sabine Schmidt (Technical Assistant)
Elisabeth Picca (Technical Assistant)