NGC 4631 in Canes Venatici is an edge-on barred spiral galaxy about 25 million light-years away, whose elongated silhouette and bulging core give it an unmistakable resemblance to a swimming whale. Its irregular shape is the result of gravitational interactions with its smaller companion NGC 4627, visible just above it. The galaxy is also notable for its powerful starburst activity, driving a large halo of hot gas extending well beyond the disc — detectable in X-ray observations.