Rinoceronte bianco estinzione

The northern white rhino is functionally extinct: why and what is being done about it

When Sudan, the last male specimen of Sudan, died in a reserve in Kenya in 2018 Northern white rhinocerosthe whole world has known its history and this species has become a global icon of nature conservation. The White Rhinoceros is one of the so-calledBig Five” together with the lion, the elephant, the buffalo and the leopard, it is part of the five large mammals symbolizing the African savannah. It is present in Africa with two subspecies: the Northern white rhinoceros (Ceratotherium simum cottoni) and the southern (Ceratotherium simum simum) and for years was a victim of poaching because of its horn. The northern subspecies was declared extinct in nature, but starting in 2015, she became the protagonist of one extraordinary assisted reproduction experiment with the use of a line stem cells. Saving this decidedly charismatic species is important for the animal itself, but also for the ecological role it plays in shaping and conserving the savannah landscape.

Characteristics, habitat and ecological role of the white rhinoceros

The white rhino is one of the 5 species of rhinos in the world. It is commonly known as whitenot due to the color of the coat which is greyish, but due to a wrong interpretation of the word wydwhich in the Afrikaans language of South Africa means “big mouth”, but has been erroneously translated with the English term white.
It is a truly impressive animal as it can weigh up to over 14 to around 36 quintals and has a length between 3.4 and 4 meters; these dimensions make it the largest of the rhinos. It has two horns and the front one can also reach 170 cm in length. The specimens are quite long-lived, given that they can live for over 40 years and they reach sexual maturity late which arrives in males between 10 and 15 years and in females between 6 and 8 years, when they are able to give birth for the first time. Also gestation is very long and lasts 16 months.

White rhino at risk

The White Rhinoceros lives there Savannah and the great African grasslandsin family groups composed of females adults with young and sub-adults who move together feeding on various herbaceous species and leaves, selecting the most nutritious ones during the rainy season, while in the arid periods they adapt to eating even less nutritious species. Due to its size it falls into the category of “Mega herbivores”, i.e. those with a tonnage equal to or greater than 1,000 kg. It is defined by the quantity of vegetation it eats and by the continuous trampling with its heavy paws a real local engineer given that it is capable of modifying the structure and composition of the vegetation of a place at the landscape level. In this way also, like any large herbivore, It also reduces the risk of fires in the area in which he lives.

The horn and the threat of poachers

The horn was the cause of its dramatic persecution: for centuries the rhinoceros has always been hunted, in the past legally, but for years now illegally for its horn, a precious object for international trade. Highly sought after in Southeast Asia for use in Chinese medicine and for ornamental purposes to make jewellery, handles of edged weapons. In hunting, specimens with longer horns are coveted, so much so that based on a study conducted by a research group from the University of Helsinki, the continuous selection carried out by hunters has today led to a greater frequency of specimens with the shorter hornbut less suited to the environment in which they live.

Trade in rhino horn

Since 1977, rhinos have been among the species listed in the Washington Convention on the Control of International Trade in Endangered Species of Fauna and Flora (known as CITES) and all trade in rhinos and their products has been banned.

Because the northern subspecies is considered functionally extinct

The northern subspecies Northern white rhinos (NWR) was originally distributed in various regions south of the Sahara. The impact of poaching on the northern subspecies has been decidedly more serious. In 1960 the total number of specimens was approximately 2,360. The last surviving wild population in a National Park in the Democratic Republic of Congo rapidly declined under the pressure of poachers until it reached few units estimated in 2006. In 2009, four of the world’s last remaining northern white rhinos, Najin, Fatu, Sudan and Suni, were moved to the Ol Pejeta Reserve in Kenya controlled by armed security 24 hours a day. A mating attempt was unsuccessful and veterinary checks showed that the two surviving females were unable to reproduce naturally. When Sudan died on March 19, 2018, thelast male specimenthe subspecies has been declared functionally extinct in the wild by the IUCN. Currently only two females survived and represent the last hope for this subspecies.

White rhino and baby

The BIORESCUE Project for the recovery of the northern white rhino

In July 2018, revolutionary international research was launched, the BioRescue project, coordinated by the Leibniz Institute in Berlin and which also includes the Department of Comparative Biomedicine and Nutrition of the University of Padua among its partners. The Northern White Rhino can be saved thanks to the application of advanced assisted reproductive technologies (aART): with the recovery of immature eggs (oocytes) from the ovaries of the two surviving donor females (OPU), in vitro fertilization (IVF) with spermatozoa of now extinct males frozen before their death and subsequent transfer of the embryos produced in the laboratory to Southern white rhino surrogate mothers suitable for completing pregnancy. To date, the BioRescue consortium has produced a total of 35 embryos with this technique currently frozen awaiting a transfer to a southern white rhino mother, which is why on January 8th he received a prestigious international award in Liverpool.

Additionally, Osaka University is attempting to produce eggs and sperm from northern white rhino stem cellsobtained by taking skin cells from a rhinoceros and then regressing them to the stem cell stage through a delicate chemical process.

The Southern White Rhino is still under monitoring

As regards the southern subspecies, Southern white rhino (SWR), endemic to South Africa, was on the brink of extinction in the late 19th century. After decades of conservation projects and translocation of specimens in the main African National Parks, including the famous Kruger Park in South Africa, a recovery of the population was evident at the end of 2012. The satisfactory growth recorded up to 2012 is slowed down over the last ten years due to new increases in poaching and recent periods of severe drought. In any case, even if he remains “a special watchdog” according to the 2020 report of the International Union for Conservation of Nature (IUCN) the subspecies is classified as near threatened, therefore it can be considered at moderate risk.