Reproductive Parameters of Wild Female Amur (Siberian) Tigers (Panthera Tigris Altaica)

We monitored reproduction of 11 female Amur tigers (Panthera tigris altaica) on and near the Sikhote-Alin Biosphere Zapovednik, Russia, 1992–2000, using radiotelemetry, capture, and conventional tracking (using snow and soil substrates). Tigers gave birth in all but 3 months of the year, with a peak in late summer (x2 = 10.68, d.f. = 3, P = 0.014; n = 19 litters from 11 mothers). Minimum age of 1st reproduction for 4 tigers was 4 ± 0.4 years (mean ± 95% confidence interval). Mean interval between litters was 21.4 ± 4.4 months (n = 7 pairs of consecutive litters for 4 tigers). Mean litter size was 2.4 ± 0.6 cubs (n = 16 litters of 9 tigers) when litter size was 1st determined but, due to 41–47% cub mortality (n = 19 litters), decreased to 1.3 ± 0.5 cubs (range = 0–4, n = 19 litters) by the time cubs were 12 months old. At least 57% of cub mortality was anthropogenic. Mean age at dispersal was 18.8 ± 1.5 months (n = 5 litters). Mean reproductive rate was 1.4 cubs/year, but only 0.7 cubs/year survived up to 12 months old. We believe that recent conclusions that tiger populations can grow and recover rapidly from substantial losses may be overly optimistic.