The Mass Extinction of the 3rd Millennium is an event that started in the 30th century, and lasted for 800 years. All the creatures that died out were large mammals.
Wumbologists don't know why this happened to the large mammals but there some theories...
- The Mega Pest Theory: This theory is based on the fact that smaller mammals and pest animals like rats, grew bigger and drove the normal big flesh eaters to extinction, many animals got over hunted and replaced by smaller animals like rabbits, who grew to fit the place.
- Climate: The world got warmer and those big mammals couldn't adapt to the weather and died off.