On the 25th June 2018, Blue World Institute received a report on a dead dolphin seen close by the Osor village. After our inspection in the field we discovered it was another case of a female dolphin mourning for her dead calf.

Bottlenose dolphins have highly developed social structure and show care for the co-members of their groups. Individuals communicate between them and create partnerships that can last for their entire life. Particularly strong relationships are created between mothers and their offspring. During the first year of their life, calves almost never separates from its mother, and females with calves often join together in groups in order to help each other and to increase protection of their calves.

In many species with developed social structure, death of a group member may represent a certain trauma. Mourning and “separating“ from a dead member has been recorded in many species including bottlenose dolphin. The process duration may vary depending on the strength of the relationship, and it is particularly long in cases of a loss of calf when female may accompany the dead carcass for days. Such cases have been documented also in Lošinj dolphins on several occasions.

Female bottlenose dolphin pushes the dead body of her newborn, Osor, June 2018.

In the case by Osor, a female is a dolphin known to us for 23 years and it was first documented in our referent catalogue of identified bottlenose dolphins in the year 1995. This female was regularly encountered in Cres and Lošinj waters and is known as a caring mother that has so far successfully raised five offspring.

As in other similar cases of mourning, also in this case by Osor the female stayed with her dead calf pushing it with its beak and trying to carry it along by her dorsal fin or fluke in the attempt to “make it move“. As our research boat was getting closer, the female showed evident signs of anxiety,shock and stress. Swimming in panic, the female attempted to push and sunk the calf trying to protect it. In order to minimise the stress, after few minutes that took us to take photographs of dolphins’ dorsal fin in order to identify it, we moved away and followed dolphins’ behaviour from the distance. After few other attempts of the female to sunk the calf, the calf finally remained under the sea surface which has substantially increased the time female was spending underwater. Along with that, the sea became very rough due to the strong north wind and researchers decided to end the monitoring.

We would like to thank Mr. Željko Černelić who reported his observation to us and sent his photographs for our first insight. We would like to ask everyone who has similar encounters to report their observations to us by phone (051/604-666), e-mail (info@blue-world.org) or our Facebook page. Also, as the summer months are generally the period when newborn dolphins are born, Blue World Institute would like to remind the boaters to slow down their vessels when in dolphin vicinity and to apply Code of conduct in order to make dolphins’ first months easier. Every, attempt of the boater to get closer, especially when aggressively pursuing the groups may induce stress and cause death of young calf.

According to the protocol on how to act in case of dead, injured and sick animals of strictly protected species, the Emergency call service 112 was informed.

Blue World Institute is a non-profit organisation that finances its conservation activities and research of bottlenose dolphin through donations and sponsorship. We would like to invite you to sustain our work by symbolically adopting a dolphin. Thank you!