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.
Heartbreaking: A dolphin carries the body of a dead calf, undoubtedly her own, off the coast of the Guangxi Zhuang region, in China. The 'mourning ritual' is rarely caught on camera
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.
He told Mother Nature Network: 'My hypothesis is that the sick animal was kept company and given support, and when it died the group had done their job. In this case they had already assumed death would eventually come - they were prepared.'
Dolphins are famed for being highly intelligent and social animals.
Out to deeper water: The dolphin repeatedly lifted the calf out of the water, as if helping it to breathe. It was also taking out to sea, perhaps because it had been killed by a boat closer in to shore
While it is difficult to compare intelligence levels between species, they are certainly considered among the smartest animals on Earth.
They appear to have a complex language, communicating to each other in a series of whistles and clicks, and have a developed social structure.
They travel in pods, which can involve strong bonds between individuals, but pods are not exclusive,. Members can join or leave pods at will. In areas of abundant food, pods can unite to form superpods of more than 1,000 individuals.
They have been observed working together to feed, forming walls of bubbles around their prey to concentrate schools of fish into balls for easier feeding.
As well as looking after their own, dolphins have also been known to protect human beings from shark attacks. Documented cases include dolphins forming a protective ring around swimmers, or charging the sharks, aiming for the fish's gills with their pointed snouts.
A dolphin named Moko was observed guiding a female Pygmy Sperm Whale and her calf away from shallow water off the coast of New Zealand, where they would have been stranded.
Moko also interacted with humans, swimming with them and playing 'fetch' with objects, until he fell foul of locals by becoming too playful and trying to stop swimmers from returning to shore - sometimes keeping them hostage for hours..
Dolphins also display culture, something long believed to be unique to humans.
They use tools, such as incorporating sticks and weeds in mating displays, and have been observed covering their snouts with sea sponges to protect again abrasion while foraging on the sea floor.
This use of tools is what experts refer to as 'learned behaviour', and is passed on from adult to child.
But it's not all fun and games. Dolphins can be capable of extreme aggression. Males almost always bear scars from the equivalent of adolescent fighting.
They are also capable of rape and murder, with regularly documented cases of dolphins killing porpoises off the coast of Scotland. The reason for this is unknown, as porpoises do not share the same diet as dolphins and, as such, pose no threat.