Oscillations in shoal cohesion in zebrafish (Danio rerio).

In many species, group cohesion may be the result of a compromise between opposing forces (e.g. predator avoidance and competition for food). However, little empirical data exists on the dynamics of group cohesion. We present moment-to-moment positional data on zebrafish shoals and analyze temporal changes in inter-individual distances. We demonstrate that the distance between shoal members does not settle at any given value, as has previously been assumed, but oscillates with a period between 5 and 15s.