Curious about Xoloitzcuintli Mexican hairless dogs? Here's everything you need about this ancient dog breed, which you may ...

Quetzalcoatlus northropi has been estimated at various weights. Some estimates are as low as 100 KG (220 lbs) and as high as ...

Tens of millions of years ago, a diverse array of bird species soared, swam, and thrived amid their scaly reptile cousins—and ...