Elephants and rhinos shrink their tusks and horns to avoid being hunted

this rhino horns they have shrunk (very) in the last century. The first photographic portraits of these animals, taken a little over 100 years ago, show them to have much longer horns. taller than we can see now. as stated by first historical analysis Regarding the evolution of this characteristic of rhinos, everything suggests that poaching is responsible for this phenomenon.

Research led by the University of Cambridge Rhinoceros photos taken between 1886 and 2018. They also included illustrations and portraits of these animals that are more than 500 years old. From there, the team of researchers who led this study, calculated the size of the horns He tracked the number of these animals in each image and the evolution of this trait in five species (white, black, Indian, Javanese, and Sumatran). Analysis of the historical record, indeed,rhino horns gradually shrank over time“. But why?

Scientists responsible for this analysis put forward the following hypothesis. Rhinos are one of the main targets of poachers. In large part, because its horns reach astronomical values ​​on the black market (mainly, medicinal and even miraculous capacities are incorrectly attributed to it in some cultures). Searching for these ‘trophies’, according to experts, Historically, hunters will shoot longer-horned rhinos more often.. This would support the breeding of small horned rhinos, and in doing so this trait would be passed on to future generations.

“Having smaller horns in the long run could hurt their survival”

“Rhinos have developed their horns for different reasons: like catching food or defending themselves against predators, so in the long run, having smaller horns, harm their survival“, highlights Oscar Wilson, author of this analysis and professor at the University of Helsinki, Finland.

historical perception

The study also explores the perceptions of these animals throughout history. For example, early rhino portraits, gigantic, menacing beings who persecute humans. In this sense, experts believe that this vision, at least initially, to justify the hunting of these wild animals. At the beginning of the last century, hunting of these animals was so normalized that even President Theodore Roosevelt posed triumphantly with a black rhino he had just killed.

Portraits of these animals from 1950 show a change of trend. Photographs of rhinos are no longer meant to showcase a hunting trophy, on the contrary, to promote the preservation. In this sense, experts suggest that this change coincided with the world. collapse of european empires. That is, just as African countries gained their independence, and in turn, European hunters began to have more restrictions on hunting in Africa.

“We found that we could use images from the last few centuries. visualize how people’s attitudes towards wildlife have changedEd Turner, a professor in Cambridge zoology and one of the researchers who led this analysis, adds, “In recent years we have seen more and more interest in rhino conservation. This can be seen in current images that show these animals in sanctuaries or depict their plight in the wild.”

Elephants are born without teeth

But something similar to what happens to rhinos Also seen in African elephants. And the characteristic of these animals is that they begin to be born without long teeth. Poaching, so rampant on the continent since 1979 – aggravated by the 15-year civil war in Mozambique (1977-1992) – has changed the genetics of this animal. thick skinned They were forced to evolve for one purpose: to survive.

However, what happened to them was not the result of Darwinian natural selection, but of mediated or artificial selection driven by the adverse conditions that man forced them to live.

Thus, a rare genetic defect seen in only 18.5% of female elephants before the war, it’s becoming an increasingly common trait, and in fact it’s already found in one in three female elephants (33%).. So suggests a new study published in the journal ScienceIt is clear that the new elephants are abandoning their precious (and valuable) ivory antlers, because they bring them more trouble than good.

ANDIn a single decade between 1979 and 1989, half of all elephants in Africa disappeared.. The ivory trade was at its peak and the price continued to rise. Poaching also financed the activities of two opposing sides in the war in Mozambique (with the sale of the teeth they bought for weapons and the meat they fed their troops), which brought the species to the brink of extinction. In fact, they wiped out almost 90% of the hardy leather population in that area.

Amid public outcry, Kenya burned its ivory stocks in protest in 1989, and the international organization CITES has since banned all international trade in ivory.

In this brutal context for animals,Those without teeth had an advantage as they saw how they were completely ignored by predators..

The study examined specimens grown and maintained in Gorongosa National Park (Mozambique). There they found that the elephants without these ivory horns were females because this is a trait linked to a mutation in the X gene, as confirmed by this same study.

This same mutation was fatal as it prevented men from developing properly in the womb. As practically the only survivors of this brutal slaughter, these tuskless elephants were the most likely to pass on these genes directly to their descendants. And so it was.

Despite the ban, they continue to hunt

However, the poaching ban did little. According to the NGO Save The Elephants, this activity remains the main risk African elephants face. The ivory trade continued to boom until less than a decade ago.

As a result, in just three years between 2010 and 2012, nearly 100,000 elephants were killed in Africa for their ivory. In fact, the wholesale price of raw ivory sold illegally in China in 2014 reached $2,100 per kilo. In 2017 the price was much lower at $730, but it’s still an issue for those with thick skin.

This genetic evolution towards toothlessness is not only seen in Mozambique. Other African countries with a significant history of ivory poaching experienced similar changes among survivors and their daughters. In South Africa, the impact has been particularly extreme: in the early 2000s, 98% of the 174 women in Addo Elephant National Park were edentulous.

The number of elephants remaining in Africa is uncertain but is estimated to be around 500,000.. Few recorded births result in a 2% to 3% annual reduction in wild African elephants around the world., according to Save The Elephants. In addition, hardy leatherbacks face other dangers from habitat loss, particularly as a result of agricultural exploitation.

Reference work: https://www.science.org/doi/10.1126/science.abe7389

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Environment department contact address:crisclimatica@prensaiberica.es