广西钦州三娘湾感人一幕：海豚妈妈背亡子回家（图）
These are the heart-rending images of a dolphin carrying her dead baby out to sea.
The pictures were taken by tourists in China's Guangxi Zhuang region, an area known for of its dolphin-watching tours.
The mammals' mourning ritual is rarely seen - and it is even more rare for it to be caught on camera.
The adult dolphin repeatedly lifted the dead calf to the surface, as if helping it to breathe. It was also moving the calf away from the shore, heading for deeper water.
A large gash was seen across the calf's belly, and it is possible the infant was killed by the propeller of a boat. Ironically, it may have been one of the many boats that take tourists out for day trips.
Researchers have observed dolphins carrying or pushing stillborn calves or those that die in their infancy. The dolphins show distress and can stay with the dead baby for several days.
Mourning rituals in the animal kingdom have also been observed in whales, elephants, chimps and gorillas.
While experts are reluctant to attribute human emotions to animals, the behaviour seems to show that dolphins are at least aware of their mortality - and may even contemplate their eventual death.
Researcher Joan Gonzalvo, of the Tethys Research Institute, observed a similar scene in 2006, where a mother was carrying its dead calf on its back. He said that the mother seemed unable to accept the death.
A year later, he witnessed a pod of dolphins trying to help a dying calf - lifting it to the surface and swimming around the sick individual in a frantic and erratic manner.