In 2004, a street in Taiwan got showered in whale guts. The putrefying whale was on route to a necropsy when pent-up gas blew a hole in its body and entrails spewed onto unfortunate passersby. One hundred to 200 million years earlier, an ichthyosaur—a dolphin-looking marine reptile contemporary to dinosaurs—died and became a fossil. Since embryos were scattered around the ichthyosaur mother’s body, some paleontologists believed the decaying animal had met an end as explosive as the whale’s.
The exploding-carcass theory has been used to explain why so many ichthyosaur fossils have been found with embryos ejected or bones oddly scattered. But as with old bones, evidence is frustratingly thin: the theory was mostly based on exploding whales as proof of principal. Scientists who want to test this hypothesis today don’t have any ichthyosaur carcasses at their disposal…but there are a lot of humans around now, many of them dead. A new study measuring gas pressure in 100 bloating human carcasses found the pressure (0.035 bar) to be nowhere near high enough to cause an explosion underwater (more than 5 to 15 bar).
Exploding carcasses are totally Discoblog’s thing, so we were a little skeptical of human corpses in a lab saying anything about ichthyosaur carcasses underwater. But humans are closer to the size of ichthyosaurs than whales, and the gas pressure difference is pretty huge. The team behind this paper has been deflating carcass explosion theories about other whacky ichthyosaur fossils too (pdf). They estimated the temperatures and water flow experienced by recently dead ichthyosaurs, which point to a prosaic cause of messy fossil configurations: currents. So it seems it was water, not explosions, that moved bones around. Yawn.
Well if we can’t have naturally exploding carcasses, we’ll just have to find some dynamite.