Recent sightings of humpback whale supergroups challenged the idea that this whale species is solitary. They were repeatedly spotted in 2011, 2014, and 2015 gathering in supergroups of almost 200 specimens around Benguela Upwelling System. They usually meet near polar regions to feed.
Humpback whales are solitary creatures and, when they meet in such supergroups, they usually do not exceed 10 or 15 specimens. However, the scientists saw them during research cruises in the Benguela Upwelling System. This represents a system of ocean currents which goes off the southwestern coast of South Africa, between Cape Point and St. Helena Bay.
Unusual whale gathering off the South African coast
First of all, the supergroup was surprising for its size, since it hosted up to 200 whales. Then, the time of the year when the scientists spotted them was a bit unusual. The whales were present off the African coast in October and November, when there was late summer in South Africa. During this time of the year, they usually migrate to Antarctica for food.
There is a study recently published in the journal PLOS One which states that the whales were indeed feeding. The fact that the whales were diving vertically and performed other peculiar movements was an indicative that they were feeding. Also, the odor that came when they cleared their blowholes was another evidence of their hunting behavior.
Why did the humpback whales gather in such large numbers?
The researchers suggest a few theories for this whale meeting. Firstly, there might be an increase of prey in Benguela System which could have drawn the humpback whales to hunt there. The study suggests that the area hosted plenty of prey that is usually on the menu of humpback whales.
The second theory lies on the fact that humpback populations have increased. Thus, a larger number of whales drives them to new feeding territories. Also, their population increase could have made them reconsider older hunting strategies.
One last explanation could be the fact that humpback whales have always hunted in the area during summer. They must have gathered in small numbers until now, so they were harder to spot. With the rapid increase in humpback populations, they have started colonizing areas that they were usually not seen roaming, such as the New York Harbor, for example.
Now that the humpback whales are again in large numbers, researchers might be able to see them engage in behaviors that they have abandoned because of their previously low number.
Image Source: Wikimedia Commons