Meet the Ologist
John Flynn

Hi, I'm John Flynn and I'm a paleontologist at the American Museum of Natural History in New York City. I research fossil mammals and the relationships between living and fossil mammals. I'm also curating an exhibition called Extreme Mammals. It showcases the biggest, smallest, and most amazing mammals of all time. Take a look at some unusual living and extinct mammals!

Cynognathus skull
Cynognathus was an early relative of mammals. It lived about 235-250 million years ago.
Cat-sized Repenomamus was the largest known mammal from the Mesozoic "Age of Dinosaurs."
Tasmanian tiger
The extinct Tasmanian tiger was neither tiger nor dog. It was a marsupial!
Kangaroos can have 3 babies, in various stages of growth, at the same time.
Spectacled bear
Spectacled bears are born immature, weighing less than 1 pound at birth.
Bootherium bombifrons skull fossil
This extinct musk-ox species has horns four inches thick.
Alaskan moose
Male moose have antlers. Antlers can grow up to 2.5 cm (1 in) a day!
A canine of the extinct saber-tooth cat (Smilodon) can be up to 18 cm (7 in) long!
A beaver's incisors and molars never stop growing throughout their life.
Woolly Mammoth
Woolly mammoths had short, thin, densely packed hairs that helped keep them warm.
The shell of an extinct glyptodont could weigh over 500 kg (1,100 lbs)!
sugar glider
Marsupial sugar gliders have a skin membrane that keeps them aloft like a parachute.
Bats are the only mammals that can truly fly.
A male platypus has bony spurs on its hind legs that can deliver toxic venom.
Scale-covered pangolins can roll themselves into a ball when they feel threatened.
Opossums can use their prehensile or grasping tails to carry nesting materials or wrap around branches like a fifth leg.
Dugongs and manatees form the only living group of plant-eating marine mammals.
boys running
Humans are extreme mammals in some ways. We have very big brains and we walk upright on two legs.

These images have been brought to you by Science Explorations, a partnership between Scholastic and the American Museum of Natural History.