Rhino horns have been gradually declining in all species over the past century, and hunting may have been responsible for this phenomenon, according to a study recently published by researchers from the University of Cambridge in Great Britain, reports DPA and the Phys science website. org, reports Agerpres.

The new study, published in the journal People And Nature, is based on an analysis of photographs of rhinos taken over the past 140 years.

According to researchers from the University of Cambridge, rhino horns are considered a financial investment, so the animals are often killed as hunting trophies.

Rhino horns are also used in traditional Chinese and Vietnamese medicine. British researchers believe that hunting rhinos with the largest horns resulted in the survival of only rhinos with small horns.

In this way, these animals pass on their morphological features associated with smaller horns to future generations.

Rhino horns have evolved to suit their habitat

“We are very pleased to have found photographic evidence that rhino horns have shrunk over time,” said Oscar Wilson, a former researcher at the University of Cambridge’s Department of Zoology and lead author of the study.

Oscar Wilson, now at the University of Helsinki in Finland, added:

“Rhino horns have evolved for a reason—different species use them in different ways, for example to find food or to protect themselves from predators—so we think having smaller horns would be detrimental to their survival.”

The researchers measured the horns of 80 rhinos photographed between 1886 and 2018, and whose horns were depicted in great detail in these images.

The photos found at The Rhino Resource Center’s online portal are of all five surviving species: white rhino, black rhino, Indian rhinoceros, Javan rhinoceros and Sumatran rhinoceros.

Research by researchers

The researchers analyzed images of these rhinos killed by poachers, including a 1911 photograph of Theodore Roosevelt, in which the former US president stands next to a black rhino he had just shot.

PHOTO: Image by Barbara Cushing / Everett / Profimedia Images

The experts also measured other parts of the rhinos’ bodies so that the length of the horns could be accurately calculated according to the proportions of the body. They also looked at a series of drawings made over a period of more than 500 years – some dating back to a period when drawings were used to keep records of animal species.

According to the data thus obtained, until the 1950s there was very little effort to promote the need for rhino conservation among the public.

“In the last few decades at least, there has been a lot more focus on rhino conservation – and this idea is reflected in recent images of their conservation in reserves or their condition in the wild,” explained Oscar Wilson.

Rhinos are an endangered species, with fewer than 30,000 remaining in the wild today.

At the beginning of the 20th century, more than 500,000 rhinos lived around the world. Three species of these animals – the black rhinoceros, the Javan rhinoceros and the Sumatran rhinoceros – are on the list of endangered species.