PROBLEM TO BE SOLVED: To provide an upper gastrointestinal catheter and a catheter system capable of highly efficiently acquiring information on heart states and the like of birds.SOLUTION: An upper gastrointestinal catheter 1 including electrocardiograph electrodes 21, 22, and 23 electrically connected to an electrocardiograph for displaying an electrocardiogram, with birds defined as examination objects comprises: a catheter body 10 that includes a bendable bending section 11 at a distal end side as an end when being orally inserted into the examination object； the three electrocardiograph electrodes 21, 22, and 23 provided at the distal end side of the catheter body 10 at prescribed intervals apart； and an acceleration sensor 30 that is incorporated in the catheter body 10 and provided at a farther distal-side position with respect to the bending section 11.
