Humpback whales are gathering in huge groups, and nobody’s sure what they’re up to

Humpback whales are typically considered solitary animals, as the huge mammals usually only travel in groups of two or three, if they travel with any others at all.

But in the past few years, scientists have noticed something strange: as many as 200 humpback whales, gathering off the coast of South Africa to feed. By comparison, researchers used to consider groups of 10 or 20 whales as large.

These massive new groups are puzzling scientists given how much food would need to be present in one particular area of the ocean to feed that many humpbacks, who each weigh about 65,000 pounds, per Popular Science. According to the NOAA, a single whale may eat up to one ton of krill, shrimp and small fish every day.

Humpback whales are typically not even seen as far north as they have been spotted feeding. Southern hemisphere whales usually feed near Antarctica in the summer and then migrate north to mate and raise their young, according to a study published by PLOSone.

“No such dense feeding aggregations have been reported elsewhere in low or mid latitudes during Southern Hemisphere humpback whale migrations,” the study’s lead author, Ken Findlay, told Time.

And lastly, most of the whales in these groups appear to be young, fueling more speculation about why whales of a certain age seem to be drawn to these large groups, per Popular Science.

However, Findlay and his team of researchers don’t claim to have any definitive answers as to why this sudden radical change in behavior has taken place. They do speculate that a recent surge in the global humpback whale population may have changed migration and feeding patterns, but they also stress that more research is needed to draw any conclusions.

In September 2016, the U.S. government removed many humpback whales — which are classified by geographic location — from its list of endangered animals, citing substantial increases in populations that had once been ravaged by hunters. According to the International Whaling Commission, the humpback whale population has increased in some regions of the world by as much as 10 percent over the past 15 years.

This story was originally published March 15, 2017 at 3:03 PM with the headline "Humpback whales are gathering in huge groups, and nobody’s sure what they’re up to."