When Humpback whales migrate along the Australian coast in their thousands, dolphins join the shoals of their large relatives. This is not an isolated case. In a recent study [1], two researchers from Griffith University in Australia searched social media and found 199 usable reports of encounters between whales and dolphins from 17 countries over a two-decade period, mainly Humpback whales (Megaptera novaeangliae) and Bottlenose dolphins (Tursiops truncatus). In most cases, the interactions can be interpreted as communal feeding, play, and harassment. The researchers conclude that interactions between these species are by no means as rare as previously thought.
Individuals of different species living in the same habitat do not only relate to each other as predators and prey, but also seek cooperation in foraging (as in the famous example of a grouper and a moray eel), in providing services (as in the case of the cleaner fish and its clients) or simply for play and fun.
This should come as no surprise to us, as we humans know very well that cooperation and play work across species boundaries, with our dog, our cat, even our fish in the aquarium, as Jonathan Balcombe reports in his book ‘What a Fish Knows’ [2]. We just need to leave behind our anthropomorphic view of non-human animals in order to open our eyes to all kinds of relationships between individuals of different species. The playful encounter between whales and dolphins is not an exception, but only one example. Why should animals behave as if only individuals of their own species are near them? Perhaps many humans behave this way, but why should animals?
We should not forget that, in the course of evolution, no species came into being just like that, but developed step by step from earlier species. And all species have evolved and lived alongside other species in the same habitat, which has been shaped by the diversity of species, including humans and their ancestors.
Speaking of humpback whales, South African researchers have disproved another truism: that individuals of this species lead solitary lives. In recent years, humpback whales have been sighted off the coast of South Africa in large groups of up to 200 individuals in regions where they were not expected. Scientists are puzzled as to the reason for this; unusually rich feeding grounds, population recovery, and changing marine ecosystems due to global warming are among the arguments put forward. However, we still know so little about marine life that it is entirely possible that Humpback whales have been living socially for a long time and we simply haven’t noticed.
PS:
The supposed solitary existence of another marine animal, the octopus, was also recently disproved. I will return to this in a later post.
Title picture:
Screenshot of Jaimen Hudson’s beautiful video ‚Whales dancing with Dolphins‚
References:
[1] The Conversation, 12.08.2025: ‚Whales and dolphins regularly hang out with each other’
[2] Book review, 08.07.2017, of Jonathan Balcombe’s ‚What a Fish Knows‚
[3] Smithsonian Magazine, 13.03.2017: ‚Scientists Spot Hundreds of Humpback Whales Feeding in Massive Groups’