Contents: The objectives of this study were to assess the effects of season, breeding activity, age and latitude on fecal testosterone metabolite concentrations in captive, adult male polar bears (Ursus maritimus). Fourteen polar bears from 13 North American zoos were monitored for 12–36 months, producing 25‐year‐long testosterone profiles. Results indicated that testosterone was significantly higher during the breeding season (early January through the end of May) compared with the non‐breeding season with the highest concentrations excreted from early January through late March. Variations in excretion patterns were observed among individuals and also between years within an individual, with testosterone peaks closely associated with breeding activity. Results indicate that fecal testosterone concentrations are influenced by season, breeding activity and age, but not by latitude. This is the first report describing longitudinal fecal testosterone metabolite concentrations in individual adult male polar bears.

Assisted reproductive technologies can aid conservation efforts via support of ex situ population management and preservation of genetic material. Data from 38 sperm collection attempts from 17 polar bears (1–5 procedures/bear) were evaluated. Sample collections were attempted via electroejaculation (EEJ; n = 6), urethral catheterization (UC; n = 25), or sperm rescue (SR; n = 7) during the breeding season (Jan. 1-May 21; n = 27) and nonbreeding season (May 22-Dec. 31; n = 11). Sperm retrieval was successful in 1 EEJ (16.7%), 18 UC (72.0%) and 4 SR (57.1%) collections. Initial sperm motility and viability were 50.0% and 77.0% for EEJ, 64.3 ± 7.4% and 80.9 ± 3.8% for UC, and 56.7 ± 8.8% and 80.5 ± 0.5% for SR. UC and SR were more likely to be successful during the breeding season (84.2–100%) than the nonbreeding season (25.0–33.3%). Testicular tumors were observed in four males (57%) during SR. In total, 13 samples were cryopreserved (n = 1 EEJ, 9 UC, and 3 SR) with egg-yolk-based equine extender (EQ) or OptiXcell (OP). For both extenders, post-thaw motility and viability were reduced by 20–60% and 30–65%, respectively. Further efforts to optimize procedures are warranted, but this summary provides data useful for enhancing the success of polar bear sperm collection and cryopreservation.

Odour-detection dogs are utilised by law enforcement to identify illegal substances, by conservation groups to locate scat from specific species, and more recently, in biomedical investigations such as cancer detection. Because dogs can detect target odours in samples that can be collected noninvasively, such as faeces, they may be useful in diagnostic evaluations of zoo animals; however, reports are scarce describing the application of odour-detection dogs in medical diagnoses of wildlife species. The objective of the current study was to investigate the reliability of a trained dog for pregnancy detection of polar bears Ursus maritimus, a species for which there is no means of noninvasive pregnancy diagnosis. Using over 300 faecal samples collected from zoo-housed polar bears, a 2-year old beagle was trained to discriminate samples originating from pregnant bears from samples collected from non-pregnant individuals. At training evaluation, the dog's sensitivity (true positive rate) and specificity (true negative rate) were 1.00. In two real-time tests performed during consecutive cubbing seasons, the dog evaluated samples collected from 16 female bears in the first year and 17 the subsequent year. The dog's sensitivity was 0.00 both years and specificity was 0.97 and 1.00 during the first and second year, respectively. The reduced sensitivity in testing versus training may be attributable to several causes, including failure to generalise the target odour to novel pregnancies. It is likely that a large number of unique cases of condition are required to sufficiently train an odour-detection dog, which may be prohibitive in wildlife studies when sample sizes are liable to be limited.