Table 4. Mean perimeter and mean area of the convex polygons formed by the groups in the three treatments of the cave (a) and the surface mollies (b).

For the groups of size 6 the reduction relative to the values of the groups of size 12 is shown. The simulation results are the mean results from 1,000 random walks. The values marked with an asterisk were obtained from a simulation with the movement rules explained in Fig. 3.

	Mean perimeter [cm]	%reduced		Mean area [cm2]	%reduced
	observed	observed	simulated	observed	observed	simulated
(a) Cave molly
G12a	187			2,172
G6	157	15	17	1,285	38	42
G12b	181			1,977
(b) Surface molly
G12a	103			620
G6	49	55	17 (39)*	93	86	42 (70)*
G12b	112			698