Table 4 Parameters of locomotion that were measured for each spiny mouse.

Level of activity

Distance traveled

Overall distance (m.) that a spiny mouse traveled during the 10-min observation.

Traveling speed

Overall traveled distance divided by the duration of locomoting periods (m/sec).

Temporal organization

Number of stops

Incidence of "non-locomoting" intervals (stops), bounded by locomotion.

Number of trips

Trips are intervals between consecutive stops at the home base, which is the place with the highest rank among zones according to the accumulated "non-locomoting" intervals. Thus, a trip comprised progression out from home base through consecutive stops in the arena, until returning to the home base.

Stops/trip

Number of stops taken between two successive visits to the home base (= total number of stops divided by the total number of trips).

Trip length

Metric distance traveled in a round-trip to the home base (total distance divided by the total number of trips).

Inter-stops distance

The metric distance traveled between two consecutive stops (or, distance traveled in a "locomoting" interval = distance divided by number of stops).

Spatial distribution

Time spent along the perimeter (%)

Calculated as percentage of the total time, in order to show how long spiny mice stayed at the vicinity of the walls of the arena, compared with the time spent in the center of the arena or near/on the stones.

Stops along the perimeter (%)

Calculated as percentage of the total stops, in order to show how many stops took place along the vicinity of the walls of the arena, compared with stopping in the center of the arena or at/on the stones.

Meander

The rate of change in direction of progression relative to the distance traveled, calculated automatically by Ethovision for each two successive time points by dividing the turn angle by the distance. Mean meander of each spiny mouse was used to calculate the mean of each group. + indicated a clockwise change in direction of progression, whereas - indicated a counterclockwise change. Thus, lower absolute (+ or -) meander values characterize locomotion along relatively straight trajectories, and higher meander absolute values describe circular or winding trajectories. It should be noted that meander is sensitive to tracking rate, animal size, and arena size. Therefore, meander may be compared only for the same animal size, same resolution, and same arena size.