[[Right. So when they began to shrink, was it caused by man?]]
Nope, it was caused by ranchers who raised wooly mamoths- as everyone knows, mammoths faRT, and farts contain methane, and methane is a gas capable of trapping heat, therefore mammoth farts are what caused global warming thanks to mammoth ranchers
I'm sure glad you explained that! Good thing they're exSTINK!