The human body, although a very efficient bit of engineering indeed, has a couple of spare parts. And these spare parts would not for the most part make much of a difference if our bodies operated with or without them. We don’t need to be equipped to mash raw plants with our teeth or process them in our digestive systems; we do not need to directionally smell predators in the distance, and we don’t really use our feet to pick things up too often. Maybe they will eventually evolve away, but for now we are stuck with them. This list presents some of the body parts that we just don’t use any more, but are still carrying around anyway.
10. Wisdom Teeth and Appendix
These flat back teeth for grinding and the tiny little internal organ help humans chew and digest the plants that they ate when we lived in the bush and literally ate leaves from the branches. Now, they provide little more use than easy practice session for young surgeons.
9. Male Nipples
Not too many men breast feeding, at least that we see. Good erogenous zones for sure, but not much real “functional use”. Lactiferous ducts – as they are officially known – form in the womb early in the stages of human development. Not knowing whether the gender will be male or female, both are born with the necessary hardware just in case – for milk feeding that is.
8. Extrinsic Ear Muscles
These are great for animals who need to be able to independently move their ears around to listen to the movement of either prey or predators, which humans could at one time most likely do. Think of how a cat or dog controls its ears. A good skill for them, not so much for humans. Aside from a neat party trick, there is really not much call for modern man to be able to move their ears from the outside.
7. Vomeronasal Organ
Ah, nothing like the fresh scent of pheromones in the morning. We have the hardware for super-scent detection, it just doesn’t work. Also known as Jacobsen’s organ, this is a tiny organ that is near, but fully enclosed and separate from, the sinus. It is lined with non-functioning chemo-receptors: the ones that animals use to zone in on smell and scent. They may be all that remains of a once powerful ability to detect pheromones, the chemical messengers that carry information between individuals of the same species. It actually remains strong in some people and is sometimes referred to as the “sixth sense” for those who have unusual abilities.
6. Palmaris Longus Muscle
Some have it, some don”t – can’t be that critical. This is a long muscle that runs from the elbow to the wrist; its function is to provide extra flexion for the hand at the wrist, which would seem like a fairly important thing for a muscle to do, and one that people would want and need. Yet, it is absent in 11-15% of the population, and so could be a muscle evolving out. Theories state that it may have at one time been important for climbing and hanging, which is less of a critical skill in the modern society, unless maybe you are born into a circus family.
5. Erector Pili
These are tiny muscles in the skin that are used to puff up the fur on animals to intimidate predators or keep warm. Some theories even state that they are leftovers from feathers, which can be individually moved on the body by birds. In modern humans, these muscles help to sustain some measure of body heat, but unless you are intensely hairy – as in a human sweater – they really serve little more use than just giving goosebumps, or “chicken skin”, in cold and tingly moments.
4. Plantaris Muscle
This is good to have if you have the fully functioning “monkey foot”. This muscle in the bottom of the foot helps grasp and hold things, such as a tree vine or object, and gives the dexterity to the toes that many primates have. It has already disappeared in an estimated 12-15% of the human population, and as vestigal muscle (no longer needed), will likely become less apparent in people over time.
Quite literally, this is the tailbone, a plated bone structure at the bottom of the spine where the tail used to be (click the picture for a larger view). Unless there are people with stuff tucked up under their pants, there just aren’t too many tailed-humans around these days. While its primary purpose is to give the tail a place to attach to the body, it does have some secondary value to the human body, so it can be argued that it is not completely useless. On the plus side, it does help, from an architectural standpoint, as an attachment for various muscles, tendons and ligaments, and gives the “tripod” base for stability when sitting. It’s also a very strong point of fact in the proof of evolution.
2. Paranasal Sinus
These are basically air-pockets in the head, just behind the face. The nasal sinuses of our early ancestors may have been lined with odor receptors that gave a heightened sense of smell, which aided survival. Other theories of why they are there include temperature regulation in the head, air bag-like protection for the muscles behind the sinus or making the head lighter, which would have potentially made a difference tens of thousands of years ago when the skull was bigger and underwent different kinds of blows. Good now maybe for boxers and MMA champs.
1. Male Uterus
First think to note: this is not a common thing, and this post does not mean to imply that it is. But it happens, and as such, is definitely of enough interest to LOP to include into this list. No doubt. So, in this instance, remnants of the Mullerian ducts have been found in the male as a uterus-like structure. Historically, these have been known as a masculine uterus. A British Medical Journal chronicles one such recorded incident. The language of the article is naturally very scientific but pretty clear in the findings. There are also several other similar documented findings of either this development. Vestigial or mistaken?