Have you seen this picture? Apparently it's been floating around on the internet for a while now, but has experienced something of a comeback as of late, usually with some version of the following caption:
The Lions Mane Jellyfish is the largest jellyfish in the world. They have been swimming in arctic waters since before the dinosaurs (over 650 million years ago) and are among some of the oldest surviving species in the world.
The largest can come in at about 6 meters and has tentacles over 50 meters long. Pretty amazing when you think these things have been swimming around for so long.
Well, I hate to break it to you guys, but you've been deceived (on the Internet, of all places). Over on Deep Sea News, Craig McClain gives a good rundown of why this photo is clearly a lie:
Lion's Maine Jellyfish are indeed big. The world record had a bell diameter of 7 and half feet (2.29m) and 120 ft long tentacles (37m).I know this because for this paper, I needed data for the largest and smallest species for every animal phylum.
Being a connoisseur of photos of all size extremes, I immediately noted something was off. Let's assume the scuba diver is only 5 feet (1.5m) in height. The width of the jellyfish's bell is about 3 of the scuba diver's length or 15 feet (4.57m). This would make it twice the size of the world's largest known specimen.
In other words: Lion's Mane Jellyfish are the largest known species of jellyfish on Earth, they're just not as big as this picture makes them out to be. Not like they have any need for photoshop, anyway; they're plenty big enough, thank you very much. I mean, come on — a bell diameter of up to 7.5 feet? I'm amazed that anyone would feel the need to make it look any bigger in the first place. [Deep Sea News]