Hot climate restricted dinosaurs from tropics

Washington

Scorching heat and dry climate were the reasons that kept grass-eating dinosaurs out of the tropics for some 30 million years, a study out Monday found.

It has been a mystery why long-necked dinosaurs seem to avoid the tropics when there were many different types of them lived at different latitudes well north and south of the equator.

Scientists working at a site in northern New Mexico worked with rocks from 215 to 205 million years ago and were able to recreate the climate from that time, the Late Triassic Period.

They found that the carbon-loaded atmosphere was as hot as 600 degree making it hard for plants and herbivores to survive. The tropical climate had humid phases and then long droughts.

"It was a time of climate extremes that went back and forth unpredictably. Large, warm-blooded dinosaurian herbivores weren't able to exist close to the equator -- there was not enough dependable plant food," study co-author Randall Irmis of the University of Utah said in a statement.