Reply to: Models of flow through sponges must consider the sponge tissue

In their Comment [1], Leys et al. question the modelling choice of our original study [2] to focus on the skeletal motifs of Euplectella aspergillum may not be suited to gain insight into the hydrodynamics within the body cavity of the sponge and its surroundings, based on two main arguments: in living sponges, (1) the skeleton is embedded within soft tissues, which rely on canals and chambers of millimetre-to-submicrometre sizes, and (2) active pumping governs the water flows through the canals. Here we provide evidence that the above comments, although stimulating an interesting perspective for future studies, have marginal bearing on the conclusions drawn in our original paper—the level of detail of which is defined by the present state-of-the-art of modelling technology.7s