* Spines are part of the skeleton: Spines are part of the vertebral column, which is the backbone of all vertebrates (animals with backbones). The length of the spine varies greatly depending on the animal's size and shape.
* Different species have different spine structures: The number of vertebrae and the way they are connected varies between species. For example, a hummingbird has a very short spine compared to a giraffe, but that's due to their different body structures, not necessarily "shorter spines".
Instead of "shortest spines," it might be more helpful to think about:
* Animals with the fewest vertebrae: Some snakes, like the small blind snake, have very few vertebrae, making their spine very short.
* Animals with short bodies: Animals with compact bodies, like small mammals or amphibians, will naturally have shorter spines.
* Animals with flexible spines: Some animals, like snakes, have highly flexible spines that can be compressed or stretched.
It's important to remember that comparing spine length across different animal species is not always a meaningful comparison.