Polar Bear Signature Project

Many questions about wild polar bears cannot easily be answered in the Arctic, where animals are widely dispersed and not easily accessible. Zoo bears provide opportunities to develop and validate new monitoring techniques under carefully managed conditions, before applying them to wild populations. By understanding normal physiology, reproduction, and health in zoo bears, scientists can better interpret findings from wild bears and develop tools that support conservation and inform wildlife management. This “bench-to-Arctic” approach allows discoveries made in zoological institutions to directly benefit conservation efforts in the wild.

Successful reproduction is the foundation of healthy, sustainable populations. Yet many aspects of polar bear reproduction remain poorly understood. CREW scientists are working to understand every stage of reproduction- from sexual maturity through reproductive aging- using a variety of approaches. These studies provide valuable information for improving breeding recommendations while advancing our understanding of polar bear biology.

Current research includes:

• Non-invasive hormone monitoring
• Biomarker discovery for pregnancy diagnosis
• Long-term reproductive monitoring
• Reproductive examinations

Maintaining genetic diversity is critical for the long-term sustainability of zoo-managed populations and information learned from zoo bears may one day help conserve genetics from wild populations facing environmental change. CREW is developing assisted reproductive techniques that allow valuable genetic material to be preserved and shared among institutions. Scientists are also refining methods for collecting, evaluating, and cryopreserving sperm for future use.

Current research includes:

• Semen collection
• Sperm cryopreservation
• Artificial insemination
• Ovulation induction
• Genome resource banking

Understanding what is “normal” is essential for recognizing disease, monitoring health, and evaluating how animals respond to environmental change. CREW researchers are establishing species-specific reference values for hormones and clinical biomarkers while developing new tools to assess health and fitness. These studies improve veterinary care for zoo bears and provide valuable baseline information for evaluating wild populations.

Current research includes:

• Seasonal hormone profiles
• Serum biomarker identification and assay validation
• Clinical pathology reference intervals
• Multiplex diagnostic assays

Using decades of records alongside modern reproductive data, CREW scientists are studying the biological and management factors associated with successful reproduction. These findings help inform breeding recommendations, improve population sustainability, and guide long-term management decisions.

Current research includes

• Demographic modeling
• Studbook analyses and population management evaluation
• Assessment of breeding management strategies

Despite their unique reproductive strategies, polar bears share commonalities in reproductive processes, such as seasonal breeding, induced ovulation, embryonic diapause, and pseudopregnancy in the absence of true pregnancy, with several other species, including other bear species, mink, otters, seals, and red pandas. The innovative approaches developed through the Polar Bear Signature Project can be applied to other threatened and endangered species.

Current projects include:

Sloth Bears

Scientists are adapting reproductive hormone monitoring, semen evaluation, and fertility assessment techniques developed in polar bears to support the conservation and management of sloth bears in human care (in collaboration with the Cleveland Zoo).

Red Pandas

CREW researchers are developing methods to monitor reproduction and pregnancy in red pandas, helping improve our understanding of embryonic diapause.