Fig. 1.

Example survival trajectories for (A) a 5-y-old whale, (B) a 15-y-old whale, and (C) a 20-y-old whale, when their grandmother is alive (red line/circles), when their reproductive grandmother has recently died (blue line/squares), and when their postreproductive grandmother has recently died (green line/triangles), where the salmon index is fixed at 1 across all years. Survival is derived from the best-fitting extended Cox proportional hazards model for grandoffspring experiencing their grandmother’s death at different ages (ages are in years). Insert shows grandmother J19 with her grandoffspring J51.