Table 1. Number of bats that participated in the study.

In the bimodal learning and cross-modal recognition experiments, bats were trained to discriminate targets and were disqualified if they failed to reach 75% correct choice within reasonable time in the original training task (i.e., before any testing began). In the sensory weighing experiment, all bats that participated in the experiment were naïve and were flown once in the two-arm maze, except for in the “acoustic detection control” where bats were trained to detect a reflective wall. In the acoustic detection control, the bats were tested with either the right side of the two-arm maze blocked or the left side. The number of bats disqualified from each condition and the reason for disqualification are indicated. The numbers given for each condition are the numbers of participants after the removal of the disqualified bats.

Experiment	Number of bats
Bimodal learning	5 (same bats as round 2 in the cross-modal recognition; one of the bats was disqualified since it did not echolocate in light)
Cross-modal recognition	Round 1: 4 (another 4 failed to reach the initial learning criterion) Round 2: 5 (another bat failed to reach the initial learning criterion)
Sensory weighing conditions:	Left blocked	Right blocked	No. of disqualified
			No. of no echolocation	No. of video malfunction	No. of refuse to fly
Black reflective wall (5 × 10−2 lux)	20	21	10	5	2
White reflective wall (5 × 10−2 lux)	20	20	8	2	1
Black reflective wall (2 × 10−3 lux)	20	20	4	2
White reflective wall (2 × 10−3 lux)	19	19	4	2	5
Black reflective wall (3 × 10−5 lux)	20	20	3		2
White reflective wall (3 × 10−5 lux)	20	18		4	8
Black nonreflective wall (3 × 10−5 lux)	61		7	1
Acoustic detection control (<10−7 lux)	10		2 (failed to reach criterion)