Humpbacks have been gathering in large groups in a bizarre never-before-seen behaviour that is baffling scientists.
The gatherings can reach 200 whales and have been spotted in the midst of mass feeding frenzies off the coast of South Africa – thousands of miles further north than their normal feeding grounds around the Antarctic.
The whales are not normally social creatures, preferring to travel and hunt alone, in pairs, or as small groups that quickly disband.
The huge mammals grow up to 16 metres in length ansd weigh approximately 36,000 kg. Despite their intimidating size, humpback whales are harmless to humans, mostly eating krill and small fish.
Humpbacks usually spend the summer months around the Antarctic where they feed on krill and build up fat stores for the winter.
In the winter months, humpback whales leave the icy waters of the North Atlantic Ocean and migrate past the UK to warmer locations.
They swim to tropical and subtropical waters where female whales give birth to new calves.
They are rarely seen in large groups, preferring to travel and hunt alone, in pairs, or as small groups that quickly disband.
One expert theory suggests that the behaviour is simply a return to sociable activity that was seen before the species had its numbers reduced 90 per cent by whaling in the early 20th century.
‘I’ve never seen anything like this,’ Dr Ken Findlay, lead author of the study from the Cape Peninsula University of Technology in South Africa, told New Scientist.
‘It’s possible that the behaviour was occurring but just not where it was visible – because there were so few of them, we may not have seen it.’
The whales could also be gathering in response to shifts in prey availability.
Despite whaling crippling their numbers, the humpback has seen a mysterious resurgence in numbers in recent years.
‘For the last few decades, suddenly they seem to have overcome some threshold and have begun to increase very fast,’ Dr Gísli Vikingsson, head of whale research at the Marine and Freshwater Research Institute in Iceland, told New Scientist.
The gatherings can reach 200 whales and have been spotted in the midst of mass feeding frenzies off the coast of South Africa.
Researchers have spotted the bizarre behaviour on three separate cruises around the Cape Peninsula of South Africa in 2011, 2014 and 2015, as well as a handful of public observations from aircraft