A video of a large pod of dolphins has been circulating in South Africa with claims that it was filmed recently and shows “unusual” fleeing behaviour. Some social media said this was a sign of an imminent natural disaster. But the claims are misleading; the video is old and shows dolphins and whales gorging themselves in Cape Town’s False Bay, a familiar occurrence in local waters often observed during the annual migration of vast shoals of fish along South Africa’s east coast.
“25 September 2023 / Mosselbay / Western Cape / South Africa / Dolphins and Whales south of Mossel Bay, swimming away from something (sic),” reads the caption of a post published on X (formerly Twitter) on September 25, 2023.
“It’s unusual for them to flee like that. Makes one wonder if they don't want to tell us something to warn us,” the caption adds.
Another post featuring the same video was shared on Facebook with a caption that reads: “I sense something is about to happen nature might be speaking to us”, while also noting the date and location as “25 September 2023 / Mosselbay”.
The video was shared several times on social media citing the location as Mossel Bay, a harbour town in South Africa’s Western Cape, and the date September 25, 2023 -- giving the impression that it was filmed recently.
The responses to the X post showed that some people believed something ominous was on the horizon, while other replies indicated that the video was old.
However, the posts are misleading; the video was recorded in 2021 and shows a typical ocean feeding frenzy, but not in Mossel Bay.
Video from 2021The landscape in the video matches recognisable peaks in Cape Town, such as Table Mountain and Devil’s Peak, which social media users noted in the comments (archived here).
A few comments included links to articles and videos from 2021 about a feeding frenzy near Cape Town off the coast of Fish Hoek, False Bay -- still in the Western Cape, but more than 400 kilometres away from Mossel Bay (archived here and here).
The video was filmed on March 28, 2021, around the time when shoals of sardines and anchovies annually venture into False Bay -- a phenomenon known as the sardine run which attracts predators and a number of divers to the country (archived here, here and here).
“We saw the super-pod of dolphins and decided to follow them. As we were following them, the other half of the super-pod was spotted swimming in from Muizenberg beach,” Kade Tame told local publication Cape Town Etc about the footage he recorded (archived here).
“We then realised that it was the same pod and [they] were doing this for a reason (gathering fish). Before we knew it, there was white water everywhere and the most spectacular feeding began.”
Dolphins and whalesDolphins are social creatures and usually feed in hunting pods using a sophisticated technique to gather and eat fish.
They hunt in groups where each dolphin has a role: the dolphin encircles a school of fish and the other members of the pod create barriers to prevent the fish from escaping, which maximises the opportunity for all to feed.
This type of movement, especially during a sardine run, is not as “unusual” as some misleading posts have claimed.
While there has been anecdotal evidence of animals, fish, birds, reptiles, and insects “exhibiting strange behaviour anywhere from weeks to seconds before an earthquake”, the United States Geological Survey (USGS) says scientists, mainly in China and Japan, are still trying to make sense of it (archived here).
Behaviours observed include leaving their homes or making unusual noises weeks or days before a natural disaster, but because such stimuli can happen for any number of reasons, it is not considered to be a reliable indicator.