Advanced telemetry for polar bear tracking

However, due to anatomical and growth constraints, only adult female polar bears can be reliably collared, leaving a significant gap in data concerning other demographics of the species.

In response, a study led by York University explored alternative telemetry devices, namely fur- and ear-mounted tags, which can be attached to polar bears of any sex and age. The primary objective was to assess the efficacy of these tags in tracking polar bear movements and behaviours, particularly during the ice-free season in Hudson Bay.

The importance of tracking polar bears

The Arctic is heating up four times faster than the rest of the world. This rapid warming is leading to longer periods without sea ice, forcing polar bears to spend more time on land where food is hard to find, which affects their health and survival.

By tracking polar bears' movements, scientists can collect important data to understand how these animals adapt to the changing environment. This information helps predict future impacts and guides conservation efforts to protect polar bears.

Data from the study revealed that polar bears spend most of their time resting when on land, but as temperatures drop and sea ice begins to form, they become more active. Specifically, the study found that polar bears rest about 70% of the time and travel 30% of the time while on land. The ongoing loss of sea ice due to climate change means polar bears are spending more time on land with limited food.

Monitoring their movements provides crucial information about how these changes affect their behaviour, energy use, and survival rates. This knowledge is vital for developing strategies and policies to mitigate the effects of climate change on polar bear populations.

Technological advancements in tracking

Traditional tracking methods involved satellite-linked radio and GPS collars, primarily used on adult female polar bears due to their neck structure. These collars were unsuitable for subadult and adult male polar bears. This led to the development of fur- and ear-mounted telemetry tags, which are more inclusive and non-invasive.

The study tested three different designs of fur tags – SeaTrkr, tribrush, and pentagon – and compared their performance to traditional ear tags. Fur tags were deployed on sixteen male polar bears, both adult and subadult, while ear tags were attached to forty-two bears captured between 2016 and 2022. The data collected from these tags was used to model the time subadult and adult male polar bears spent resting versus travelling while on land.

Fur-mounted tags

These tags are attached to the polar bear's fur using mechanisms such as copper ferrules and nylon brushes. SeaTrkr tags, equipped with GPS/Iridium transmitters, provided higher resolution and more frequent location data. However, fur tags generally had shorter functional durations compared to ear tags, likely due to the nature of attachment and the bears' behaviour, including grooming and interaction with the environment.

The findings indicated that the three fur tag designs remained functional for shorter durations compared to ear tags. SeaTrkr tags averaged 58 days of functionality, tribrush tags lasted for an average of 47 days, and pentagon tags functioned for about 22 days.

Ear-mounted tags

Ear tags have proven to be more durable, remaining functional for a longer period. These tags are smaller and lighter, reducing the risk of detachment and injury. Ear tags are secured through the bear's ear, making them less prone to incidental removal compared to fur tags. Ear tags remained operational for an average of 121 days.

Despite these differences in retention times, the positional error estimates among the tags were comparable, with GPS/Iridium-equipped SeaTrkr tags providing higher resolution and more frequent location data.

Implications for conservation

The study concluded that while collars remain the best option for long-term, high-resolution data collection from adult female polar bears, fur-mounted tags show great promise for short-term applications and for tracking bears of other sex and age classes. Fur tags can be particularly useful during critical periods such as the spring hyperphagia, mating seasons, and transitions on and off the sea ice. Additionally, these tags could be valuable in mitigating human-bear conflicts by allowing for temporary monitoring of problem bears near human settlements.

The data gathered also informs international conservation efforts, ensuring that policies are based on robust scientific evidence. Continued innovation in tracking technologies and methods will be essential as the Arctic continues to warm, further altering the habitat and behaviours of its iconic inhabitants.

Tracking polar bears using advanced telemetry tags enhances our understanding of polar bear ecology and plays a crucial role in conservation efforts. These innovations are vital for protecting polar bears and the Arctic ecosystem in the face of rapid climate change. By continuing to refine these technologies and methodologies, researchers and conservationists can better protect polar bears and the delicate Arctic ecosystem they call home.