Dolphins are highly intelligent mammals. They belong to a family that includes orcas and pilot whales. They have a long history of interacting with people on boats, in the oceans and in captivity. In the wild, they form close-knit family pods that communicate through echolocation. They also use echolocation for hunting purposes.
In 1992, a feeding program began at Tangalooma Island Resort on Moreton Island, Australia. Staff would wade out into the water and feed fish to up to twelve wild bottlenose dolphins (Tursiops species) at a time. This program continues to this day. Several years ago, the dolphins began to reciprocate with the occasional gift of fish or squid. Thus far there have been 23 incidents of gift-giving recorded. All of the dolphins that have been reported participating in the gift-giving have also been spotted at the provisioning program.
In the wild, dolphins hunt co-operatively. A group will corral a school of fish and take turns swimming through the centre and eating the fish. All of the gifts offered back to staff have been common food items such as eels, tuna, squid, an octopus and various other species of fish.
Recently, Bonnie Holmes and David Neil of the University of Queensland in Brisbane, published an article in Arthrozoos detailing the behaviour. Gift-giving is a common behaviour between animals of the same species. It is much more unusual between two individuals of different species. The most commonly occurring example of interspecies gift-giving is when domestic pets such as cats and dogs bring their owners gifts of mice, birds and other prey.
Food sharing is usually indicative of one of three things. It may be reciprocal, a belief that the recipient is a poor hunter or an invitation to play. The authors of the article believe the dolphins are offering the food as a way of inviting play. There has only been one other report of gift giving by a dolphin relative. A false killer whale, also a member of the dolphin family, was recorded giving a National Geographic photographer a mahi mahi while swimming in the wild. The photographer accepted the fish and then offered it back to the cetacean, who took it and swam away.
Ongoing studies have concentrated on communication with dolphins using underwater keyboards. Marine scientists in South Korea have also videotaped dolphins attempting to keep a dying pod member afloat by forming a line of five dolphins underneath the individual and using their backs to keep the ill dolphin from sinking. It is obvious that people still have much to learn from these very complex animals. It has long been postulated that they are one of the most intelligent species on the planet. Maybe, with further study, humans will understand the motivation behind the gifts and other behaviours.