Over 30 great white sharks were recently observed eating a 36-foot-long Brydes whale in the waters off of Cape Town, South Africa, according to the Save Our Seas Foundation.
The whale was a free lunch for the hungry sharks, since it had already died, likely due to a boat strike or trawl net damage. Instead of hauling it off for disposal, researchers placed it near a known great white shark feeding spot, Seal Island.
According to Alison Kock, the principle scientist for the Save Our Seas Shark Center and Shark Spotting Program, the sharks immediately spotted the whale and ate their fill over a week-long period, but mostly munched during the first two days. By the time they had finished, the whale's body had been reduced to just bone and muscle.
In Kock's blog, which also shows some of the photographs, she writes that great white sharks maintain a pecking order, with larger sharks dominating over smaller ones.
She explained, "On the first day we recorded the largest sharks, over 4 meters (13 feet), taking advantage of the best opportunity to feed on the ‘choice cuts’ available. Thereafter, we recorded the smaller sharks taking their opportunity."
"A couple of sharks sported fresh superficial bites from other white sharks, just a few puncture wounds from the top teeth of another, maybe indicating that shark forgot his manners (understandably perhaps) in the presence of the feast on offer," she added.
Usually great white shark attacks on Cape fur seals at Seal Island are over in less than 1 minute, according to Kock. The sharks therefore have to be rather scrappy to get some meat. In this case, however, the giant whale was like a Thanksgiving turkey dinner with leftovers. The bounty eliminated "the need for fierce competition…allowing them to feed side by side."
Kock and her team also noticed that the sharks were very selective.
She wrote, "One might expect that they would simply eat as much as they could on whatever part of the carcass was available. But this wasn’t the case at all. They targeted the energy rich blubber, often making repeat 'test bites' (where no flesh removed) and only removing flesh once they had determined it was what they wanted."
Blubber, she explained, has more nutritional value and calories than muscle.
Kock and her group said they "documented numerous examples showing that the sharks knew exactly what they wanted (the blubber) and if they got a mouthful of muscle they often spat it out. This may provide some insight into why so many bites on humans (over 70% of white shark bites http://www.flmnh.ufl.edu/fish/sharks/isaf/isaf.htm) are a bite and release only."
Also, check out this video on shark finning that features Kock. It includes some remarkable footage of great whites, and shares an important message about conserving these apex ocean predators.
Finally, Sean van Sommeran, executive director of the Pelagic Shark Research Foundation, just reminded me about the book Great White Sharks in United States Museums. We'd all rather see the sharks alive in the oceans, but such information is valuable to researchers. You and a guest can visit a museum for free in the U.S. on Saturday, September 25. You'll just need to print out the ticket featured on this Smithsonian page. Many museums across the country are participating.