Interspecies interactions are some of the most fascinating things we can observe in the wild. Simple words, yet they open the door to complex questions about social behaviour, learning, and cetacean culture.

During one of our tours, we encountered a small group of dolphins. Two individuals were separated from the rest of the group and appeared to be travelling together. One of them was incredibly small, at first glance, it looked like the tiniest dolphin calf we had ever seen, barely noticeable on the surface from a distance.

The little calf displayed behaviour often associated with very young cetaceans, spending extended periods floating at the surface before diving. The larger individual remained close by, surfacing alongside it and diving with it, seemingly acting as a caretaker.

As we continued observing, other members of the dolphin group approached. On several occasions, individuals surfaced very close to the calf and appeared to make physical contact with it. The interactions were intense and raised even more questions about what we were witnessing.

After getting better views, we began to notice features that suggested the calf might not be a dolphin at all. Based on its size, body shape, coloration, and dorsal fin, it appeared more likely to be a harbour porpoise calf.

If that was indeed the case, what was the story behind this unusual association?

We can only speculate. The calf may have become separated from its mother and found itself among dolphins. It is also possible that one or more dolphins adopted a caregiving role. While rare, cross-species adoption and alloparental care have been documented in cetaceans, including cases where dolphins have been observed caring for calves of other species. Researchers are still trying to understand why these relationships occur, but possible explanations include strong maternal instincts, social bonding, or responses to orphaned calves.

At the same time, interactions between dolphins and porpoises are not always friendly. In some regions, aggressive encounters have been documented, reminding us that the social lives of cetaceans can be far more complex than they appear from the surface.

We may never know the full story of this particular calf. What we do know is that moments like these remind us how much there is still to learn about the animals that share our oceans.

Every tour has the potential to surprise us. Sometimes, the most unforgettable sightings are not the ones we expect.