Harbour porpoise Although conjoined twins are rarely seen in wild mammals, the first known case of a two-headed harbour porpoise was documented in May 2017 when Dutch fishermen in the North Sea caught them by chance. A study published by the online journal of the Natural History Museum Rotterdam points out that conjoined twins in whales and dolphins are extremely rare. The harbour porpoise species is widespread in cooler coastal waters of the North Atlantic, North Pacific and the Black Sea. The populations in these regions are not continuous and are classified as separate subspecies with "P. p. phocoena" in the North
Conjoined twins over the religious objections of their parents, Michaelangelo and Rina Attard. The twins were attached at the lower abdomen and spine. The surgery took place in November, 2000, at St Mary's Hospital in Manchester. The operation was controversial because Rose, the weaker twin, would die as a result of the procedure as her heart and lungs were dependent upon Grace's. However, if the operation had not taken place, it was certain that both twins would die. Grace survived to enjoy a normal childhood. In 2003, two 29-year-old women from Iran, Ladan and Laleh Bijani, who were joined at the head