Elephant tusks are one of the most notable features of giant mammals, among their sizes and trunks, which give these animals their majestic appearance. However, some elephants do not have tusks, and a high proportion of these elephants are females. Why do some female elephants not have tusks? This article answers.
What Are Tusks?
Tusks are continuously growing incisors. Typically, adult elephant teeth comprise 12 premolars, 12 molars, and two tusks. These twin teeth are composed of four layers, the outermost being the enamel. Beneath the layer of enamel is dentin, cementum, and then pulp. The pulp is a combination of blood vessels and nerve endings. The density of dentin in elephant tusks is why elephant ivory is more sought after than other animal ivory.
Baby elephants have baby tusks that often grow up to two inches before they lose them after about a year. Permanent tusks emerge when the elephants reach two years. Since elephant tusks continually grow, they can be used to determine the age of adult elephants.
What Are the Purposes of Tusks?
Elephant tusks can grow over 10 feet, with the largest tusk ever measuring about 11 feet and five inches, according to the Guinness World Record. These large teeth can look menacing and imply that they are used for defense. However, tusks serve other purposes for elephants, such as debarking trees and digging underground for salts, minerals, and water sources during dry seasons.
Elephants utilize their tusks like shovels to scoop off the earth to dig. These dug holes are often beneficial to other animals, weaker than these giant mammals and incapable of digging such holes themselves.
Another purpose that the tusk serves is to protect the trunk. The elephant trunk is boneless and mostly made up of muscles. While elephants can lift an incredible weight with their trunks, the long nose can easily be injured. Hence, elephants protect their trunks with their tusks and sometimes rest them on their sturdier teeth.
Male elephants generally use their tusks for defense. While herds of elephants can easily defend themselves against most predatory threats by stumping, males often use their tusks to fight against other males during periods of high testosterone. Younger males with smaller tusks avoid fights with older elephants.
Do Female Elephants Have Tusks?
There are two broad species of elephants, the African and Asian elephants. Both sexes of African elephants still have tusks. However, a recent study revealed that many females are born tuskless. While there is a large proportion of tuskless females, tuskless males are extremely rare.
While male Asian elephants have tusks, female Asian elephants do not grow tusks. However, about 50% of the female population grows smaller incisors that sometimes protrude under the upper lip like tusks.
Why Do Some Female Elephants Have Tusks?
According to BBC, two teeth genes are responsible for the formation of tusks in elephants, and they are the AMELX and MEP1a genes. The AMELX gene produces enamel and cementum, two materials that are present in teeth and tusks in elephants.
MEP1a, on the other hand, is crucial in the formation of dentin, the core mineral in tusks. The study was made on African elephants, which grow tusks in both sexes. It was then argued that the presence of the two genes in female and male elephants can ensure the growth of tusks.
Why Do Certain Female Elephants Not Have Tusks?
Scientists have tried for years to solve the mystery of the lack of tusks in female elephants. It was initially observed as a rarity, especially in African elephants, much like albinism. However, in recent times, tusked cow elephants have become the minority. This population density switch is blamed on two major reasons; female genetics and heavy poaching.
1. Female Genetics
Tuskless female elephants have always existed. However, they have only been rare, about 2% to 5% in herd populations. According to the New York Times, tusk growth genes are on X chromosomes, and females have XX chromosomes, while males have XY chromosomes. Male elephants die if these genes are missing. However, some female elephants can survive without these genes.
Some quarters believe that the female survival rate without these genes is due to the high survival rate of female elephants without tusks. These elephants can survive equally, using their size and trunks.
2. Heavy Poaching
According to the Telegraph, a genetic mutation may have been triggered in elephants due to heavy poaching. The observation of the elephant population recovery in Mozambique indicated a higher proportion of female elephants born without tusks.
Scientists believe that the new genetic mutation was caused by the tuskless survivors of the Mozambique war from 1977 to 1992 and passed their genes to offspring. It was observed that two-thirds of the newborns were females and half were tuskless. A similar human impact is believed to have affected the Asian elephants also.
Furthermore, heavy poaching of “big tuskers,” male elephants with large tusks, removes them from the breeding gene pool. Thus, strong and long tusk genes cannot be passed onto the next generation. In theory, if all tusked elephants are poached, it leaves the lucky tuskless males to procreate with the females, increasing the number of tuskless offspring.
This can also prove detrimental to the general population of these large herbivores as this genetic mutation can spell the end of male elephants, affecting the population as elephants are not asexual.
Small Tusks: What Are Tushes?
According to reports, about 50% of Asian female elephants have tushes, while some males share the same features. These extended upper incisors are similar to tusks in placement, as they also protrude from under the upper lips of these elephants. However, tushes are not made of the same material as tusks, lack dentin, and are more brittle.
A clear distinction between tushes and tusks is length. While tusks can grow longer than 10 feet, tushes reach a maximum of two inches. Tushes, however, can regrow when damaged, unlike tusks.
Elephant Tusks: What Are They Made of & What’s Their Purpose?
Tuskless Elephants: Why Do Certain Elephants Not Have Tusks?
Do Elephants Have Teeth? Their Dentition and Tusks Explained
Meet the Gigantic Ancient Elephant with FOUR Deadly Tusks
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- JV Chamary, Available here: https://www.sciencefocus.com/news/has-ivory-poaching-triggered-the-evolution-of-tuskless-elephants/
- , Available here: https://www.nytimes.com/2021/10/21/science/tuskless-elephants-evolution.html
- Will Brown, Available here: https://www.telegraph.co.uk/global-health/climate-and-people/mozambique-elephants-born-without-tusks-evolutionary-response/
- , Available here: https://www.guinnessworldrecords.com/world-records/70455-longest-tusk