This animation pictures a school of fish led by a larger fish that
roams through the water in a zigzagging pattern. When it encounters a
cylindrical obstacle, the school splits into two groups: one group
consisting of a few fish passes by one side of the obstacle, while the
other group comprising the remaining majority passes by the other side
following the lead fish. As soon as the fish in the smaller group have
cleared the obstacle they speed up to rejoin the school (see
Fig. 
).
| Xiaoyuan Tu | January 1996 |