A trap for catching animals, in particular muridae, comprising: - a tank; - a passageway extending from an entry along a longitudinal direction above said tank; - a container arranged at the end of said passageway and adapted to contain a bait; - a gangway movable between a closed configuration, in which it defines a floor of said passageway, and an open configuration, in which it lets an animal fall from said passageway into said tank; said gangway comprising: a) a first trapdoor hinged about a first rotation axis, which is fixed, horizontal and orthogonal to said longitudinal direction, so as to rotate between a substantially horizontal position, corresponding to the closed configuration, and a tilted position, corresponding to the open configuration; b) first return means exerting an action to bring and keep said gangway into the closed configuration; c) a second trapdoor, which is arranged after said first trapdoor along said longitudinal direction, said longitudinal direction starting from said entry; d) a hinge; said second trapdoor comprising a first and a second end portion (20,21) which are opposite to each other; said first end portion of said second trapdoor being next to said first trapdoor; said first end portion of said second trapdoor is hinged by said hinge to said first trapdoor rotatably about a second rotation axis, common to said first end portion and said first trapdoor, and parallel and spaced apart with respect to said first axis, so as to transfer, to said second trapdoor, downward forces due to a weight which rests, in use, on said first trapdoor; characterized in that said gangway further comprises: - attach means supported by said second end portion of said second trapdoor and connecting said second end portion of said second trapdoor to fixed retaining means which prevent said attach means from lowering when said gangway is arranged in the closed configuration, so as to support said first trapdoor in its substantially horizontal position despite said weight on said first trapdoor; said attach means being releasable from said fixed retaining means in response to said weight resting on said second trapdoor. - a tank; - a passageway extending from an entry along a longitudinal direction above said tank; - a container arranged at the end of said passageway and adapted to contain a bait; - a gangway movable between a closed configuration, in which it defines a floor of said passageway, and an open configuration, in which it lets an animal fall from said passageway into said tank; said gangway comprising: a) a first trapdoor hinged about a first rotation axis, which is fixed, horizontal and orthogonal to said longitudinal direction, so as to rotate between a substantially horizontal position, corresponding to the closed configuration, and a tilted position, corresponding to the open configuration; b) first return means exerting an action to bring and keep said gangway into the closed configuration; c) a second trapdoor, which is arranged after said first trapdoor along said longitudinal direction, said longitudinal direction starting from said entry; d) a hinge; said second trapdoor comprising a first and a second end portion (20,21) which are opposite to each other; said first end portion of said second trapdoor being next to said first trapdoor; said first end portion of said second trapdoor is hinged by said hinge to said first trapdoor rotatably about a second rotation axis, common to said first end portion and said first trapdoor, and parallel and spaced apart with respect to said first axis, so as to transfer, to said second trapdoor, downward forces due to a weight which rests, in use, on said first trapdoor; a) a first trapdoor hinged about a first rotation axis, which is fixed, horizontal and orthogonal to said longitudinal direction, so as to rotate between a substantially horizontal position, corresponding to the closed configuration, and a tilted position, corresponding to the open configuration; b) first return means exerting an action to bring and keep said gangway into the closed configuration; c) a second trapdoor, which is arranged after said first trapdoor along said longitudinal direction, said longitudinal direction starting from said entry; d) a hinge; said second trapdoor comprising a first and a second end portion (20,21) which are opposite to each other; said first end portion of said second trapdoor being next to said first trapdoor; - attach means supported by said second end portion of said second trapdoor and connecting said second end portion of said second trapdoor to fixed retaining means which prevent said attach means from lowering when said gangway is arranged in the closed configuration, so as to support said first trapdoor in its substantially horizontal position despite said weight on said first trapdoor; said attach means being releasable from said fixed retaining means in response to said weight resting on said second trapdoor.