Skip to content

Why are Tsavo’s male lions maneless?

Tsavo’s maneless lions gained their notoriety in 1898 when the British colonial project aimed at constructing the Uganda Railway was in full swing. During the construction of a bridge over the Tsavo River, a pair of maneless male lions, infamously known as the “man-eating lions of Tsavo,” struck terror by allegedly killing over 28 people working on the railway bridge.

These lions would haunt the construction camps, dragging workers from their tents, and devouring them, causing widespread panic and halting work on the bridge. Lieutenant Colonel John Henry Patterson eventually managed to hunt and kill the pair which are now displayed in the Field Museum of Natural History in Chicago.

More than a century later, Tsavo continues to be the residence of a rare phenomenon, a population of maneless male lions, setting them apart from their counterparts across Africa. In this article, we explore the reasons behind lion’s manes and unravel the intriguing story behind Tsavo’s unique adaptation.

Why do lions have manes?

The striking mane of a male lion is an iconic feature of the African savanna, instantly setting them apart and, interestingly, posing a potential challenge to their hunting success. While it was once commonly believed that a lion’s mane primarily served as protection during confrontations with rival males, contemporary understanding leans toward a different perspective. Today, it is widely held that a lion’s mane functions as a visual display of fitness and virility, similar to the impressive feathers developed by bird species like peacocks.

When does a lion gets its mane?

Male lion cubs start growing longer hair around their chests and necks at about 12 to 14 months of age, marking the beginning of their mane development. However, it won’t be fully developed until they reach the age of two.

As they age, the mane typically becomes longer and darker, extending across their bellies and backs. Researchers have discovered that female lions exhibit a mating preference for lions with larger and darker manes. The manes act as signals to a long and healthy life and, more importantly,  desirable genes to pass on to future generations.

Why does a lion lose its mane?

Manelessness in male lions can be attributed to various factors. Older males, especially those that have engaged in territorial battles for a pride, might lose their manes if they sustain injuries they cannot recover from.

Stress or a drop in testosterone levels can also result in the loss of a mane. Often, stories of maneless lions attacking humans surface. Theories suggest that an ousted male, having lost its pride and its mane, become more desperate without the help of female lions for hunting, thus resorting to alternative sources of food, such as humans.

Tsavo’s maneless males

In the Tsavo Conservation Area, it’s common for male lions not to develop full manes, with some having none at all. This isn’t the result of losing a mane due to stress or injury, but rather an evolutionary adaptation towards reduced mane development to better suit their environment.

One line of thought suggests that mane development in lions is closely linked to climate and temperature regulation. It’s believed that the presence of a thick mane can significantly reduce heat loss, making it more prevalent in cooler regions.

An alternative explanation suggests that the absence of a mane in Tsavo’s lions could be an adaptation to the thorny vegetation of the area. In this thorny landscape, a full mane might hinder their hunting abilities. It’s plausible that the lack of a mane in Tsavo lions results from a combination of both climate and hunting adaptation factors causing an evolutionary shift away from larger manes to smaller manes.

Unique social structure

Tsavo’s lions have not only made a mark with their manelessness but also with their distinctive social structure, which sets them apart from other lion populations. In the Mara-Serengeti ecosystem, prides are often ruled by coalitions of male lions, with pairs or trios of males working together. Single male lions typically struggle to maintain a pride on their own. However, the lions of Tsavo depart from this pattern, as they are exclusively led by single male lions.

The reasons behind this unique social structure remain largely unknown. One possibility is that the relative scarcity of game in the Tsavo conservation area may lead male lions to be less willing to share their kills. As a result, coalitions of male lions may not be sustainable. Studies have also suggested that Tsavo lions possess higher testosterone levels, which could lead to increased aggression among male lions, leaving less room for cooperation.

In the Tsavo Conservation Area, we’re fortunate to encounter a diverse array of extraordinary wildlife, from the majestic super tuskers traversing the arid terrain to the infamous maneless male lions, forever etched in history as the “man-eaters. These Tsavo lions have not only adapted their appearance to suit the climate but have also fine-tuned their social structure for survival.

Back To Top