Minimum population estimates
The minimum population size as of 2019 included bears identified in
2019, including bears that died in 2019; bears not identified in
2019–2020, but whose presence as of 2019 was inferred by pedigree
reconstruction; and bears ≥1 year old, identified not in 2019 but in
2020. The second category included existing bears (i.e., bears
identified only before 2019) and hypothetical bears generated by the
COLONY software, as described above. In the third category, the age or
minimum age of bears was determined based on the year of first genetic
identification (i.e., bears identified before 2019 were included), the
year when their parent was dead, or on the video data obtained at the
time of genetic identification. The combination of a DNA-based parentage
analysis and video data taken at the hair-trap site sometimes enabled us
to determine the age of young bears (i.e., 0–1 years old) that
accompanied their mother. Some bears were confirmed to be ≥1 year old
when their DNA was collected, and their body sizes were able to be
assessed by the video data. Significant differences in body sizes
between 0- and 1-year-old bears enabled us to determine if bears were ≥1
year old, even if information regarding their age was unavailable. This
assessment was done only when we could identify the bear in the video
clip with 100% confidence. Therefore, bears that had the possibility of
being cub-of-the-year were not included in the minimum population size
as of 2019.