New research suggests that a volatile climate that swung wildly between wet and dry periods kept large dinosaurs from thriving at lower latitudes for millions of years. Evidence also suggests that fires were prevalent during dry periods, limiting resources available to large animals like dinosaurs.

Colby Research Scientist in Geology Ian Glasspool, an organic petrologist, measured the reflectiveness of chunks of fossilized charcoal in rock layers marking ancient dry periods to estimate the temperatures of wildfires that produced the charcoal. According to Glasspool, one fire reached 680°C, hot enough to melt an aluminum can.

“That’s a pretty hot fire,” Glasspool said. “There was probably a lot of fuel there.” He added that a drought that dried out large areas of vegetation could have provided the fuel necessary to generate that kind of heat.