At Tsavo Trust, our core mission is to protect the remarkable Super Tuskers of the Tsavo Conservation Area. These elephants, known for their immense tusks, are not only symbols of Africa’s natural beauty but also vital to the ecosystem. Last week, we introduced you to the 10 Super Tuskers still roaming Tsavo, and now we explore a pressing question: Does tusk size impact mating success, or is there more to the story?
While it’s tempting to think that larger tusks are the key to reproductive dominance, the reality is more nuanced. In fact, while tusk size does play a role in sexual selection, it’s a male elephant’s musth period that truly dictates mating success. Let’s break down how tusk size and musth interact in the complex dynamics of elephant reproduction.
The appeal of large tusks
There is evidence to suggest that female elephants are drawn to bulls with larger tusks. This preference could be tied to the evolutionary advantage of selecting mates with such impressive features. Large tusks take significant time and energy to grow, and a male who manages to produce them has demonstrated his ability to survive, thrive, and resist disease. Essentially, by choosing a bull with large tusks, a female is selecting for proven genes—traits that will benefit her offspring in terms of both survival and resilience.
Many animals possess traits that are more pronounced in males and serve as indicators of survival fitness—think of a lion’s mane or a peacock’s feathers. These secondary sexual characteristics often signal health and vitality, helping to attract mates. While tusks can certainly reflect a bull’s overall fitness, they are not the only factor influencing mating success.
Why musth is more important
In elephant society, it’s musth, not tusk size, that largely dictates which bulls get to mate. Musth is a period of heightened testosterone levels in male elephants, during which they become more aggressive, dominant, and sexually active. Bulls in musth often win mating rights over non-musth males, even if they are smaller or have less impressive tusks. This is because a bull in musth is more driven and assertive, while a non-musth bull lacks the same intensity and determination.
Older bulls, which are typically larger and possess longer tusks, also tend to sustain musth for extended periods. The longer a bull can remain in musth, the more likely he is to find and mate with receptive females. Younger bulls, on the other hand, have shorter more sporadic musth cycles, meaning they are less likely to have the opportunity to mate.
Female choice and musth
Females don’t just passively wait for a musth bull to approach them—they actively choose mates, often preferring males in musth. There is evidence to suggest that females will avoid non-musth bulls, even if they have larger tusks or appear physically superior in other ways. Musth signals the male’s reproductive readiness and his ability to sustain high body condition. This condition is essential for producing offspring with traits linked to fitness and survival, such as resistance to disease and the strength to maintain dominance.
The role of dominance hierarchies
Musth also plays a critical role in resolving dominance hierarchies among male elephants. It often eliminates the need for costly physical combat between bulls, which could result in serious injury or death. Although larger males usually dominate smaller ones, musth status overrides size discrepancies. In some cases, a smaller bull in musth can even exclude a much larger, non-musth male from gaining access to females. This interplay of size, musth, and dominance creates a dynamic and complex social structure in elephant populations.
Interestingly, in habitats like Tsavo, where resources vary seasonally, older bulls will often go into musth during the rainy season when food and water are more plentiful. This allows them to stay in musth for longer periods and secure more mating opportunities. Younger bulls, by contrast, enter musth when conditions are less favorable, or when dominant males are absent, giving them a brief window to mate without facing overwhelming competition.
Tusk Size vs. Musth: The Final Word
While large tusks may catch the eye of female elephants and signal strength and health, it is musth that ultimately governs reproductive success. Older, larger bulls with extended musth periods are far more likely to mate and pass on their genes than their younger counterparts, regardless of tusk size. However, older bulls are also more likely to have larger tusks meaning the two come hand-in-hand.
At Tsavo Trust, we recognize the incredible value of protecting these majestic bulls, especially the Super Tuskers of Tsavo. Their long tusks are more than just symbols of grandeur—they represent a lifetime of survival and success in a challenging environment. But as we’ve learned, the story of elephant mating success is far more complex, with tusks and musth both playing key roles in shaping the future of elephant populations.