Did giant octopus kill ichthyosaurs found in Nevada?
October 12, 2011
In what Nature Magazine dubbed “Kraken versus ichthyosaur,” a paleontologist has issued a paper saying the fossilized marine reptiles at Berlin-Ichthyosaur State Park in central Nevada were killed by a giant cephalopod -a squid- or octopus-like creature.
Mark McMenamin of Massachusetts’ Mount Holyoke College presented his theory Monday at the annual meeting of the Geological Society of America in Minneapolis. He estimated the animal would have been some 90 feet long, more than double the size of any living cephalopod, and he likened it to the Kraken of mythology.
There are nine fossilized remains at the site, some with a length of 50 feet long.
McMenamin said octopuses are among the most intelligent creatures in the oceans.
“It’s a very odd configuration of bones,” he said, adding that one of the strangest features is that some of the bones seem to have been rearranged into a pattern resembling the arrangement of suckers on a cephalopod’s tentacles. He said octopuses and squid in large aquariums have been known to collect objects and play with them.
He suggested that the cephalopod preyed on the ichthyosaurs, either drowning them or breaking their necks, then dragging them to its den to eat. He pointed to the numerous broken ribs and twisted necks of the fossils, saying there is evidence of more damage to the skeletons than an accidental death would cause.
According to Nature Magazine, scientists have struggled since the fossils were discovered in 1928 to understand how so many ichthyosaurs died in one place. Speculation includes that the air-breathing reptiles were killed by a toxic algae bloom in what was an inland sea 228 million years ago and washed ashore together. Other scientists have suggested they died in a mass stranding, like modern whales.
McMenamin said those theories have flaws, including that evidence at the site near Austin that indicates the ichthyosaurs died at different times, not all at once. He said geological evidence also indicates the water was several hundred feet deep at that time, not shallow.
But according to Nature writer Sid Perkins, McMenamin’s theory drew criticism from scientists including Roger Hanlon, a marine biologist at the laboratory in Woods Hole, Mass.
“There is nothing in the scientific literature that suggests that modern-day cephalopods do anything like this,” he said.
James Wood, formerly of the Waikiki Aquarium in Hawaii, said octopuses do sometimes play with shiny objects. And they do pile rocks outside the mouth of their dens.
“They’re curious creatures,” he said.
But he said there is no evidence that they bring animal remains home.
“I’ve yet to find a vertebrate bone in a cephalopod midden,” he said.