vestigial traits

Requested by hermit-crab-horror

Dunsparce is based off of the mythical Tsuchinoko, a strange creature known as the “bee snake” that digs through mountains and can jump over a meter high. There’s no creature quite like dunsparce in our world, which makes it such an interesting one to examine.

First of all, let’s talk about that tail. Dunsparce’s tail is a drill, which it uses to dig backwards into the ground. The drill shape helps dunsparce dig, by letting it easily push dirt and rocks out of the way, in a similar way to how earthworms dig around. Most animals don’t dig backwards: not being able to see where you’re digging obviously gives you a disadvantage. However, the mole can move backwards as fast as it can move forwards. This is a good thing, because in tight tunnels underground, there’s not always enough room to turn around if you need to make a quick retreat.

As for dunsparce’s tiny wings, they are best categorized as vestigial. Vestigiality refers to traits that were used by a species’ ancestors, but over the course of time and evolution have lost their function. A few good examples would be the human appendix, or our wisdom teeth. Our ancestors needed them to survive, but they have since become all but useless. dunsparce’s tiny wings are vestigial; ancient dunsparce were probably some of the best flyers, with large and functional wings, but over time dunsparce lost the need for wings, so their wings evolved to be smaller and less effective. Kiwis and Ostriches also have vestigial wings: They can’t use them to fly, but they still sometimes help out with balance or movement. 

So why did ancient dunsparce lose use their wings? The easiest answer is that they moved underground. In small burrows, there’s not much space or room to fly around in, so there’s not much need for wings. Of course, that begs the question to why the ancient dunsparce started digging in the first place, if it had full reign of the sky.

As it turns out, there are many species of flying animals that dig burrows. Many ants have wings, and they build elaborate anthills underground as their nests. Several species of wasps also dig their hives underground in a series of tunnels. Dunsparce, with its wings and its stinger-like tail certainly shares some traits with a wasp. And, of course, there’s the burrowing owl:

Building nests underground provides a lot of protection and advantages, even for flying creatures. Ancient dunsparce likely started digging their nests, and subsequently spending more and more time underground. So much time that they lost the need to fly and thus lost functionality of their wings.

As a little more to this theory, let’s think about typing for a moment. If ancient dunsparce had fully functional wings, it probably wasn’t just a normal type like modern dunsparce is. It’s easy to imagine a flying, buzzing dunsparce as being a bug or even a flying type pokémon. Either Bug or Flying would give it a weakness to Rock-types. If it burrows underground a lot, that might prove to be a problem. So that might be another factor as to why dunsparce lost its wings. Over time with evolution, dunsparce that were more resistant to rock-types were the better burrowers. They were also the dunsparce that had had smaller and less functional wings, and the dunsparce that had a pure Normal typing. In favor of being a better burrower, dunsparce lost its bug/flying typing, and with it the use of its wings.

Ancient Dunsparce once had fully functional wings, but over time through evolution they became vestigial. As the species started burrowing underground, it lost the need and use of its flight.