Dolphins are undoubtedly one of the more social species in the animal kingdom. They are also known to prepare their food before eating it and have particularly interesting sex lives.
Now, add another anomaly to the list of dolphin oddities: superpods. Dolphins are congregating in the hundreds off the coast of South Africa. The strange bit? Scientists can’t figure out why.
It’s a well-known fact that Indo-Pacific bottlenose (Tursiops aduncus) dolphins hang out in large pods, but research published in Marine Mammal Science says more than 50 animals is unusual (although it does happen).
Populations off the Wild Coast of South Africa have skyrocketed. In recent years, pod sizes have nearly tripled; in 2008, an average pod had 18 dolphins, whereas eight years later that number increased to 76.
Now, dolphin pods in the area have been clocked in at an average 325 dolphins.
And those pods are growing and forming superpods – a large group of cetaceans from different extended families.
These congregations in Algoa Bay, a shallow inlet off the Eastern Cape, had as many as 600 dolphins – the largest group size ever reported.
Typically, researchers say they expect large groups to be found in open, deeper water and small groups to hang out in shallower, coastal protected areas. But that’s not the case here.
Researchers have been studying the superpods since 2014 at three sites in South Africa. A total of 180 surveys recorded almost 20,000 dolphins in Algoa Bay and just 4,444 along the Wild Coast.
This recent case has scientists stumped, who say the reason for the growth in pods is a mystery and needs further research.
Typically, dolphins form in large groups when food is plentiful, when they are threatened by a predator (like the white shark), or apparently for no reason at all.
It’s not the first time this has happened, either. In 2015, a “megapod” of over 1,000 dolphins was filmed off the coast of California. Two years before that, thousands of dolphins were spotted near San Diego.
However, researchers say the mass groupings can be deadly. More dolphins in an area means higher competition for food, as well as a higher risk of transmitting diseases and parasites.
It also can help clue scientists in to a changing world. Dolphins are apex predators and are a good indication of the health and richness of their habitats. Studying them can provide key information on ecosystem health because of the amount of resources they need to stay healthy.
The bottlenose isn’t the only cetacean to form superpods, either. Killer Whales also form them off the San Juan Islands every year. In fact, whale lovers have made an annual conference out of it.
Considering whale and dolphins could be as social as we are, maybe it’s just one big family reunion?