The story that a tagged great white shark has been eaten by another great white shark is making headlines around the world. Various news outlets like UPI are reporting that “Australian scientists are searching for a “mystery sea monster” that likely devoured a nine-foot-long great white shark they’d been tracking.” and People magazine is saying it was a “colossal cannibal great white shark” and even stating that it’s size is “estimated at 16 feet long and over 2 tons”
Wow, that is amazing! They not only know that this shark has been killed, they also know what killed it and even estimate the size of the killer. How the heck did they do that? Estimate the size and species of a predator by the temperature of a tag. And here I was, finding it incredible that another guy claims to be able to do that by the shape of a dorsal fin.
So let’s look at a few facts. The great white sharks do indeed maintain a body temperature of a few degrees above the water temperature. According to Elasmo-research.org, great white sharks maintain a muscle temperature of 7-9 degrees f, and a stomach temperature of 13-25 degrees f above water temperature. The scientists claim that the tag could not have fallen off, because it would have recorded a lower temperature first, before the jump to the higher temperature, after it was eaten. So if that were true, that would put the maximum temperature inside a great white shark stomach at 64 degrees and not 78.
Since the tags we are talking about here, are external, they record the temperature of the water and not that of the sharks muscle. Therefore, they would not have recorded a lower temperature after falling off. The fact that it plummeted straight down to 1900 feet is a further indication that the tag fell off. If another shark had attacked this 9+ ft great white, there would have been a struggle and they would not just have plummeted down. Also, the typical attack behavior of a great white shark is to strike and let the prey die, not fight with it and take it down deep.
Having watched great white sharks at Isla Guadalupe for 13 years, I’ve seen them fight, bite each other and noticed that the smaller sharks tend to stay away from the bigger ones. Those actions always seemed to be a way to establish the pecking order and not an attempt to kill and eat the other shark. As a matter of fact, when we encountered a dead shark a number of years ago, all the other sharks stayed away from the area for a while, indicating that they weren’t comfortable being in an area with a dead one of their own.
I have no problem saying that I have no idea what happened to this shark, but for the scientists to state that a “colossal cannibalistic shark” ate this individual, simply because of the temperature recording of a tag, is not very scientific at all.
This whole thing happened 9 years ago. So why is this all over the news now? Well, according to People, The Smithsonian Channel repackaged an Australian documentary called The Search for the Ocean’s Super Predator into another doc called Hunt for the Super Predator.
So all this is done to promote a “documentary” by the Smithsonian channel. Why am I not surprised that after “Nat. Geo” and “The Discovery Channel” they are just going after sensational headlines to boost their ratings as well. Let’s just scare the heck out of people by letting them believe that there are monsters lurking in the Ocean. It’s not like people don’t have an irrational fear of sharks already. It’s not like they are killing sharks based on this irrational fear. No, they need to stoke that fear so that they can sell their stupid “documentary”. Damn the consequences!
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