Over the past 125,000 years, mammals on Earth have become smaller. Ten thousand years ago the average mass of a mammal was 200 pounds and today the average mass is about 15 pounds. After dinosaurs became extinct, mammals became larger and new species developed. But when ancient humans evolved, they began hunting bigger animals. Eventually, in all areas populated by humans, the size of mammals became smaller and led to extinction in many cases. Listen to hear more about the effects humans have had on the size of mammals.
Story Length: 2:34
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January 17, 2018
1:48
Paleontologists now have proof, as a result of a recent discovery of fossil remains, that giant penguins existed long before whales even entered the ocean. It's an ancient species of penguin that swam off the coast of New Zealand between 55 and 60 million years ago, soon after dinosaurs became extinct. The smaller penguins we know today stem from prehistoric penguins that were once the size of a human. Listen to learn why these animals went extinct and the timeline of their existence.
Read MoreSeptember 22, 2016
3:24
Sharks can live to be over two hundred years old, and recently a Greenland shark was found who may have lived up to 512 years. These sharks are the longest living vertebrates known to exist. They can be found swimming in the Arctic seas, where researchers are spending time studying the old creatures. Listen to the story to hear more about this fascinating species.
Read MoreAugust 27, 2015
3:31
Are animals faster than humans? Common sense says horses are faster, but scientists say humans have the edge in marathon distances. Ancient man used to chase his dinner; thus, people have adapted to run long distances. This adaptation is put to the test every year in England when humans race horses on a 22-mile course through Wales. It’s an annual competition that started in 1980. Listen to find out who won the race this year and who has evolved to be faster.
Read MoreFebruary 18, 2014
4:29
50,000 years ago, the arctic was not icy—but grassy, full of life and of course, woolly mammoths. After studying these giant animals’ DNA found in feces and soil, scientists hypothesize their extinction may be due to a flower. Listen to this story to find out why.
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