Fig. 4. (A) The proportion of time spent in the water (y) versus pup age (x) (y=24.3+2.57x, r²=0.20). (B) Maximum daily swimming speed versus pup age (y=1.109+0.027x; r²=0.10). (C) Average daily swimming speed versus pup age (slope of regression not significant). The numbers above the error bars in A–C correspond to the number of pups for which data were recorded. (D) Proportion of dives of 6 m or deeper (N=1118) that were classified as U-dives by cluster analysis versus pup age (y=0.192+0.022x, r²=0.59). The numbers above the data points in D are the total number of U-dives performed by pups of the given age. Dive characteristics were measured using time/depth recorders deployed on 13 nursing harbour seal pups on Svalbard, Norway. Error bars are ±1 S.D.