Table 2. AIC value for each linear model describing the effect of body density deviation on stroke efforts. Underlines indicate the minimum AIC of each individual.

	Elephant seal
Model	1	2	4	Baikal seal
Null	−114	−572	−815	−1230
Squared horizontal speed	−128	−579	−895	−1232
Absolute density deviation	−112	−585	−880	−1287
Squared horizontal speed & Absolute density deviation	−130	−606	−906	−1287

Note that the elephant seal 1 had a delta AIC of 2, compared between models including and not including absolute density deviation. It suggests less evidence to select the more complex model, which might be caused by relatively small sampling number (n = 12 + 19) in comparison with other seals (Table 1).