Aggressiveness of a Neomys fodiens parous female towards conspecific and N.anomalus intruders

Reactions of a Neomys fodiens (Pennant, 1771) parous female [FP] to 4 conspecific and 3 N. anomalus Cabrera, 1907 intruders were studied quantitatively in enclosure (135 x 135 cm) experiments. Total time of observations was 30 hr. FP initiated 5.6 intraspecific conflicts per 1 hr (1.95/hr of these were pouncings and fightings) with adult males, 0.8 conflicts/hr with a juvenile female, and 4.7 conflicts/hr with a N. ano­malus adult male. Reactions of N. fodiens parous female were several times more aggressive than interactions between non-breeding 'residents' and 'immigrants' of both water shrew species tested under the same conditions in earlier studies.