Several years ago a coal mine in Columbia turned up some fossils, which is quite common for industrial digging sites, and they sometimes even let paleontologists play with their finds. This particular dig included a good bit of vertebrate material, including some really big crocs and turtles.This was packaged and sent up to the Florida Natural History Museum where, one day, a grad student named Alex got to a sample labeled as “croc vertebrae” while unpacking the fossils. Alex, who is something of a crocodile expert, said something along the lines of “This is definitely not a crocodile.”Alex and Professor Jonathan Bloch eventually figured out that what they had on their hands must have come from a snake. A snake that dwarfed their collection's 17 foot anaconda.At this point they decided to include fossil snake expert Dr. Jason Head, who quickly realized that they had found the largest snake ever known to science: a 42-foot giant they named Titanoboa. I believe I should now have your complete attention.This find has generated a lot of excitement, so much so that the Smithsonian Channel made a documentary about the discovery called Titanoboa: Monster Snake. The movie does an excellent job representing how paleontology actually gets done, but what I especially enjoy is when discoveries like these get taken to a whole new level.You see, it's really easy to get excited by finding the biggest, longest, whatever-est thing that ever lived. I feel that excitement myself. However, the utility of those kinds of discoveries in actually helping researchers better understand the world is fairly limited. It's only once people calm down enough to start asking questions about what the largest snake ever means do I really start to get revved up.So, in this instance, we have a very large snake. What can we glean from that?First, it's important note that reptiles do not grow the same way that mammals do. Mammals have determinate growth. We have a rough size outlined in our genetics and we grow dependent on environmental factors until our growth plates fuse then we're pretty much done. The adult you isn’t getting any bigger, unless you count your waistline. Reptiles, on the other hand, have indeterminate growth. They grow faster while young, and slower once they reach adulthood, but as long as they're alive they'll keep growing.Second, we need to remember differences in temperature regulation. Mammals maintain a consistent temperature by heating themselves internally from energy obtained in our food. This is good for an energetic lifestyle, but can lead to problems like over-heating, hence elephants’ big ears, which acts like big, cooling radiators. For heterothermic reptiles, excess warmth is an invitation to have a higher metabolism, which means more food gets eaten, which means more resources with which to grow.In other words, reptiles can grow faster (and larger) in warmer environments. These two points converge in such a way that the size of a given reptile can tell us something about the temperature in which it lived. Neat, right?By using the size of modern Anacondas as compared to the temperature in which they currently live, we can establish a baseline to then apply to Titanoboa in the Paleocene (58-60 million years ago). There's obviously math involved at this point, but we're just going to ignore it for now. Think of it this way: current temps limit Anacondas to growing to a certain maximum size. Since we know Titanoboa was much larger, the environment must have been larger, right?Estimating the size of Titanoboa from the skeletal elements we do have and plugging that size into our equation yields an environment with an average temperature around 30.5° C (PDF). That’s much hotter than the modern average equatorial temperature of around 18° C (64.4° F).This estimate is actually above the maximum temperature that can be predicted using another method called leaf-margin analysis (PDF), which says that at average temperatures around and above 30 degrees C, the chemicals that make photosynthesis possible start to shut down. Clearly, the world was very different at the beginning of the age of mammals.So yes, fossils of giant animals are always grounds for excitement, but it is also important to remember that the story need not end there. Clever people can use seemingly unrelated data to discovery even more about our planet. And at the very least we can now argue against allowing continued global warming from a perspective of avoiding consumption by terrifying monster snakes.
Advertisement
Advertisement
Advertisement