toadschooled:

Here’s something spooky for today! The skeleton of an American toad [Anaxyrus americanus] articulated and on display at the Smithsonian Museum of Natural History in DC. The bony projections along the chest are not actually ribs, and in fact, most frogs lack ribs or a diaphragm at all. The shape and weight of ribs against the chest can be a dangerous trait for animals that move by hopping. If they fail to land on their front feet they could easily break their ribs. Therefore most frogs have evolved to not have ribs, while simultaneously improving the mechanisms that allow them to land safely on their front feet after a jump. Image by Flickr user

Ash.