Humans, like many other mammals, have canine teeth. These are the slightly pointed teeth located on either side of our incisors. Canine teeth have several important functions, including tearing food, grasping items, and defense. However, there is some debate over whether human canine teeth today are the ideal length for performing these functions. Some argue that our canine teeth should be longer for optimal performance. In this article, we’ll explore the evidence around optimal canine tooth length and consider the arguments for and against longer canines.
The functions of canine teeth
As mentioned above, canine teeth serve multiple purposes:
- Tearing and cutting food – The sharp points of the canine teeth pierce meat, fruit, vegetables, and other foods. Their shape allows for cutting and tearing pieces off those foods.
- Grasping objects – The canines’ position in the mouth and their pointed shape makes them useful for firmly gripping objects.
- Defense – In many animal species, the canine teeth play an important role in self-defense and establishing dominance hierarchies. Longer canines may enable more effective defense.
To best perform these functions, especially tearing, canine teeth need to be fairly long and sharp. But there are limits to how long they can practically be. Next, we’ll look at how canine tooth length varies between species and consider what the ideal length may be for humans.
Canine tooth length between species
Canine tooth length differs greatly among mammal species depending on their dietary niches and natural history. Here are some examples:
- Gorillas have very long canine teeth, with lengths over 2 inches in mature males. Their long canines are likely for display and defense.
- Lions have canines around 1.5 inches long. These assist with capturing and killing prey.
- Humans have much shorter canines, averaging just 0.5-1 inch in length.
- Fruit bats have extremely short canine teeth at just 0.1 inches long. They simply need to pierce fruit skin and lack the other canine functions present in predatory mammals.
This huge variation shows that ideal canine tooth length depends greatly on the species and its needs. Next, we’ll focus in on the canine teeth of our closest evolutionary relatives.
Primate canine tooth length
Our closest primate relatives provide clues about what our ancestral canine teeth may have been like. Here are the average canine tooth lengths for a few key primate species:
| Species | Average upper canine length |
|---|---|
| Gorilla | 25.5 mm |
| Chimpanzee | 17.0 mm |
| Orangutan | 13.7 mm |
| Baboon | 18.0 mm |
| Gibbon | 11.7 mm |
| Rhesus macaque | 10.5 mm |
| Humans | 9.2 mm |
A few key observations:
- Male primates tend to have longer canines than females. The numbers above are for males.
- More herbivorous primates like gorillas and baboons have longer canines. This may be for display and defense.
- More omnivorous primates like chimpanzees, gibbons, and macaques have moderately long canines. These assist with eating meat.
- Modern human canines are much shorter than all other great apes.
This evidence shows human canine teeth have become markedly shorter over evolutionary time as our diets and lifestyles changed. Next, we’ll look at the debate around whether they are currently the right length.
Are human canine teeth today the ideal length?
Given how much shorter human canine teeth have become compared to our primate relatives, some argue they are now suboptimally short. Anthropologist Robert Corruccini published a famous paper in 1984 titled “An epidemiologic transition in dental occlusion in world populations” where he argued that shorter canines and less prominent jaws in modern humans are causing changes in dental occlusion that affect chewing and possibly cause problems like jaw joint pain.[1]
Key points in this argument include:
- Shorter canines prevent proper guidance of incisor teeth closure and cause over-eruption of incisors.
- Lack of heavy chewing and tougher diets in modern societies is leading to underdeveloped jaw muscles and weaker bites.
- More dental problems like impacted third molars and crossbites are linked to shorter canines and jaws that are too short.
Based on this view, Corruccini and some others believe human canine teeth today are too short for ideal function and should be longer.
However, the mainstream view among dentists and anthropologists today is that current human canine tooth length is appropriate for our modern dietary needs and lifestyles. Reasons for this view include:
- Most people can effectively chew, tear, and grasp food using existing canine teeth.
- Longer canines could increase the risk of dental trauma and injury.
- Displaying longer canines for social signaling is no longer essential in modern humans.
- Shorter canines may have co-evolved along with cooking food and eating softer diets.
- Most dental occlusion and orthodontic issues are multi-factorial and not due solely to canine tooth length.
So while an evolutionary perspective can explain why our canines are much shorter than other primates, most experts think they are now at an appropriate length for optimal function today.
Conclusion
In summary, canine tooth length has shortened greatly during human evolution compared to our primate relatives. Some have argued human canines today are too short for ideal function. However, mainstream dental science indicates our current canine tooth length is appropriate for modern lifestyles and diets. While reasonable cases can be made on both sides of this debate, our canine teeth seem well-adapted to perform their necessary roles in most people. Those with dental occlusion issues may require orthodontic treatment regardless of natural canine tooth length.
Frequently Asked Questions
What are the main functions of canine teeth?
The main functions of canine teeth are tearing and cutting food, grasping objects, and defense. Their pointed shape allows them to pierce into foods or threats.
Why do primates like gorillas have such long canine teeth?
Male gorillas develop very long canine teeth, up to 2 inches long. This is likely to display their strength and fitness to mates and intimidate rivals. Their length is less about serving a utilitarian function.
Are problems like overbites connected to shorter modern human canines?
Some anthropologists have argued that shorter canine teeth contribute to dental misalignment issues in modern humans. However, most orthodontists today view this as an oversimplification, as many factors can cause malocclusion.
Would longer canines make it easier for humans to eat tough foods?
Maybe slightly, but we have multiple ways to alter and soften food textures with tools and cooking. Most people can chew and tear meat and other foods effectively with our current canine teeth.
If longer canines aided defense, why did they shrink in humans?
As humans developed more complex tools, culture, and language, close-range physical defense became less essential. So the selective pressures favoring very long, intimidating canine teeth likely diminished.
