Polar bears: cub survival and behaviour

A new type of “proximity” tag that records presence/absence of cubs close to their mother is currently being developed by SIRTRACK. The new tags will be deployed on polar bears for the first time in a pilot project planned for spring 2007, in Svalbard.

This new technology will facilitate the documentation of cub survival at different ages, as well as their general spatial behaviour in relation to their mother. Cubs are usually dependent on their mother for at least the first one and a half years of life and they nurse from her several times a day. When they are within a few meters of their mother, the receiver she wears will get a signal from tiny transmitters on her cub(s). If her tag does not receive a signal over a period of more than a few hours for young cubs, it means that the cub has died. At an older age (2-2.5 years), a signal failure can indicate that the cub is dead, but it is more likely to indicate when the cub and mother have parted company (weaning time).

Capture of cubs at a later time will give new information about the influence of the age of cub independence on other life history traits. This technology will also be very useful for studying polar bear mating behaviour if it is deployed on mating pairs.

Prosjektleder: Dr. Jon Aars