Is there a limit to animal size? Could Godzilla actually exist? Tune into this episode to hear Art and Marty talk to Jon Harrison and Jim Brown. ​​​​​​​Jon Harrison (Arizona State University) studies the physical limits to insect body size and furthered our understanding of the giant insects that once roamed our planet. Luckily for us, his research indicates that Mothra may never exist. Jim Brown (University of New Mexico) famously put forth the universal quarter-power scaling law, which predicts how many ecological and evolutionary variables (including metabolism, life span, reproduction) of plants and animals change with body size. For example, his theory was able to explain the fact that all mammals average the same number of heartbeats (~ 1 billion) over their life time, regardless of how large they are (mice to elephants) or how long they live (3 years or 70 years)! Elephants hearts just beat really slow.