A trap for animals, in particular rats or mice, and for being arranged on a substantially horizontal floor, where this meets a substantially vertical inner or outer wall, said trap comprising: a trap housing comprising an inner passageway which a rat or mouse may run into; at least a first flange and a second flange that are connected substantially at right angles to the effect that the trap can be arranged in two positions, where the substantially horizontal floor meets the substantially vertical inner or outer wall, wherein the flanges (4, 5) of the trap and the substantially horizontal floor and the substantially vertical inner or outer wall, in both positions, span a volume which is delimited such as to define a passage in which a rat or a mouse may move when the one flange abuts on the substantially vertical inner or outer wall while the other flange abuts on the substantially horizontal floor forming the passage that a rat or a mouse can move into; wherein said inner passageway extends from the one flange and the passage and into the trap housing, said inner passageway and trap housing comprising: a trigger mechanism, a killer mechanism and a bait box, said killer mechanism acting by a striker mechanism (10, 11), said bait box being located at the interior end of the inner passageway, characterized in that the killer mechanism is constituted by a blade (10, 11) and that the trigger mechanism of the trap comprises two light sensors and two light emitters, wherein the light beams of the two light emitters are configured to hit the two light sensors, and the blade (10,11) is moreover configured such that it is released when the two light sensors do not register light at the same time. a trap housing comprising an inner passageway which a rat or mouse may run into; at least a first flange and a second flange that are connected substantially at right angles to the effect that the trap can be arranged in two positions, where the substantially horizontal floor meets the substantially vertical inner or outer wall, wherein the flanges (4, 5) of the trap and the substantially horizontal floor and the substantially vertical inner or outer wall, in both positions, span a volume which is delimited such as to define a passage in which a rat or a mouse may move when the one flange abuts on the substantially vertical inner or outer wall while the other flange abuts on the substantially horizontal floor forming the passage that a rat or a mouse can move into; wherein said inner passageway extends from the one flange and the passage and into the trap housing, said inner passageway and trap housing comprising: a trigger mechanism, a killer mechanism and a bait box, said killer mechanism acting by a striker mechanism (10, 11), said bait box being located at the interior end of the inner passageway, characterized in that the killer mechanism is constituted by a blade (10, 11) and that the trigger mechanism of the trap comprises two light sensors and two light emitters, wherein the light beams of the two light emitters are configured to hit the two light sensors, and the blade (10,11) is moreover configured such that it is released when the two light sensors do not register light at the same time.