Rodents? Weasels?

During our nature walk on Sunday, I was quizzing Jonathan about the difference between a weasel and a mink. (We had just strolled by Mink Pond in Concord). He has a pretty vast knowledge of animals, and he knew the difference, explained it, and I've already forgotten.

Nevertheless, the whole discussion made me curious. While browsing on a website called Brain Pickings, I came across a recommended science book from 2011 called "Trees of Life: a Visual History of Evolution" by Theodore W. Pietsch. It had this interesting image,

but it didn't satisfy my curiosity because all the Latin names do not identify the animal for me. So I found a few other websites, including Wikipedia. Here are some fun facts. 

The African pygmy mouse is one of the smallest rodents. 

The capybara is the world's largest living rodent. 

Ever growing incisors

"Rodents are mammals of the order Rodentia, characterized by a single pair of continuously growing incisors in each of the upper and lower jaws which must be kept short by gnawing.

Forty percent of mammal species are rodents, and they are found in vast numbers on all continents other than Antarctica. Common rodents include mice, rats, squirrels, porcupines, beavers, guinea pigs, and hamsters. Rodents use their sharp incisors to gnaw wood, break into food, and bite predators. Most rodents eat seeds or plants, though some have more varied diets." from Wikipedia.

Add to this list: voles, groundhogs, lemmings, chinchillas, gerbils, muskrats, chipmunks, agouti, prairie dogs, marmots, woodchucks, and gophers. 

I remember having a discussion with my ex girlfriend. She's an exotics vet. Most people think that rabbits are rodents, but they are not. Bats are also not rodents, nor are weasels or minks, which I probably don't have to tell Jonathan. 

(in case you want to know, apparently rabbits were classified as rodents until 1912, when they got their own class). 

Finally, if you think rodents cause humans problems now, consider the giant beaver of prehistoric times. It was the size of a black bear.