Tool use promotes dental health: Using tools increases foraging success in sea otters and protects their teeth from damage

Across the animal kingdom, different types of adaptation have evolved that allow animals to access otherwise inaccessible prey. These range from morphological adaptations, such as elongated fingers in aye-aye lemurs (Daubentonia madagascariensis) (1), to behavioural adaptations, such as prey drop-ping by corvids, gulls, and raptors (2) and tool use in birds and mammals (3). Using tools, such as sticks and stones, for ex-tractive foraging allows animals to access highly nutritious prey but also incurs time and energy costs (4). It is, therefore, gen-erally assumed that the benefits of tool use outweigh the costs for this behaviour to be maintained in a population (5). However, quantifying these benefits-especially in terms of fitness-remains challenging (6).On page 798 of this issue, Law et al. (7) re-port that tool use allows southern sea otters (Enhydra lutris nereis) to increase foraging success while reducing tooth damage, di-rectly linking the physical benefits of tool use to improved overall fitness.