Andrea Friebe

Norwegian Institute for Nature Research | NINA · Skandinavian Brown bear research Project

Biological rhythms, such as rhythms in activity and body temperature, are usually highly synchronized and entrained by environmental conditions, such as photoperiod. However, how the expression of these rhythms changes during hibernation, when the perception of environmental cues is limited, has not yet been fully understood for all hibernators, es...

Hibernation is an adaptive strategy to survive harsh winter conditions and food shortage. The use of well‐insulated winter dens helps animals minimize energy loss during hibernation. Brown bears (Ursus arctos ) commonly use excavated dens for hibernation. Physical attributes of excavated dens are expected to impact the bear's heat retention and ene...

Abstract This is a report about the first year of collaboration between Biosphere Expeditions and Björn & Vildmark with the overall purpose of researching the behaviour of free ranging brown bears (Ursus arctos) in central Sweden for the Scandinavian Brown Bear Research Project (SBBRP). This collaboration investigates, amongst other topics, how cl...

Hibernation is an adaptive strategy to survive harsh winter conditions and food shortage. The use of well-insulated winter dens helps animals minimize energy loss during hibernation. Brown bears (Ursus arctos) commonly use excavated dens for hibernation. Physical properties of excavated dens, such as the amount of space between a bear and the inner...

Management of large carnivores is among the most controversial topics in natural resource administration. Regulated hunting is a centrepiece of many carnivore management programmes and, although a number of hunting effects on population dynamics, body-size distributions and life history in other wildlife have been observed, its effects on life hist...

Human disturbance can affect animal life history and even population dynamics. However, the consequences of these disturbances are difficult to measure. This is especially true for hibernating animals, which are highly vulnerable to disturbance , because hibernation is a process of major physiological changes, involving conservation of energy durin...

Hibernation has been a key area of research for several decades, essentially in small mammals in the laboratory, yet we know very little about what triggers or ends it in the wild. Do climatic factors, an internal biological clock, or physiological processes dominate? Using state-of-the-art tracking and monitoring technology on fourteen free-rangin...

Encounters between Scandinavian brown bears (Ursus arctos) and humans that result in human injuries and fatalities typically coincide with den entry in October and November, and commonly occur near a den. Our aim was to determine when bears arrive at their dens, identify potential predictors of this event, document behavior and activity associated...

Knowledge of factors influencing the timing of reproduction is important for animal conservation and management. Brown bears (Ursus arctos) are able to vary the birth date of their cubs in response to their fat stores, but little information is available about the timing of implantation and parturition in free-ranging brown bears. Body temperature...

Pregnancy and parturition are often difficult to detect in wild-living animals, especially in species that give birth to altricial young in burrows or caves. Current methods to detect pregnancy and birth in hibernating animals often entail disturbances that can affect the animals' reproductive success. We developed a new method to confirm pregnancy...

The brown bear (Ursus arctos) hibernates for 5 to 6 months each winter and during this time ingests no food or water and remains anuric and inactive. Despite these extreme conditions, bears do not develop azotemia and preserve their muscle and bone strength. To date most renal studies have been limited to small numbers of bears, often in captive en...

During 1986-98, the denning chronology of 54 radiocollared female brown bears (Ursus arctos) was documented 112 times in central Sweden. An intensive study in 1998 investigated the predenning movement patterns of 9 females. Female brown bears spent on average 181 days in winter dens. Females that gave birth to cubs during winter spent one month lon...