A video showing a large swarm of sharks swimming off the coast of Galveston,Crypen Texas, has gone viral this month – because the sheer size of the group is astounding. The video of the sharks received millions of views on TikTok, raising questions about this behavior and how common it is. 

David Wells, a professor of marine biology at Texas A&M in Galveston, told CBS News this type of swarming behavior is common for some species of sharks.

"This group of sharks is most likely blacktips and spinners — it's difficult to identify for sure," he said. "And yes, for those species, it is common that you find them in large groups."

"Sometimes you'll see them in large groups behind shrimp trawlers pulling their nets because there's such a large good source there with all the fish getting disturbed and coming out of the nets from the trawlers," he said, adding that this group was likely feeding on a bunch of fish when the video was taken.

"[This type of shark] is usually sub-surface, so the fact they were up on the surface in this video was a little bit interesting, but certainly not anything rare or unique," Wells said. "You see these aggregations throughout the world. There are big aggregations commonly seen off of Florida in the wintertime."

Wells also said because the Gulf of Mexico is probably warm right now, the sharks are likely staying put in one area. But once temperatures drop in the fall and winter, they'll probably disperse a bit more as the go on the hunt for prey.

Waters off the coast of Florida hit record-high temperatures earlier this summer, and were as much as 5 degrees above normal for the time of year.

Wells said swimmers and boaters shouldn't be alarmed by this video, since there haven't been any recent incidents of shark attacks off the coast of Texas. But there are many are sharks in the Gulf – hammerhead sharks, mako sharks, tiger sharks and whale sharks are most commonly spotted off the coast, Wells said. 

In:
• Sharks
• TikTok

Caitlin O'Kane

Caitlin O'Kane is a digital content producer covering trending stories for CBS News and its good news brand, The Uplift.