There were two reasons why I wanted to visit Ngala Reserve at the Kruger National Park in South Africa last year: I had just learned about the birth of not only one but two of the three white lions in the wild, and also, I was hoping to see the Southern White Rhino and with some luck, a Black Rhino… The poaching crisis has been so severe in the last decade that there are places in Africa where rhinos are completely extinct. The Kruger National Park is now home to the largest population of rhinos in the wild and the world's most concentrated site of commercial rhino poaching. Another reason to learn more about this charismatic species.
As soon as we set foot in our camp, we went out on the look for traces of rhinos. We were lucky to have with us the company of Solly, a ranger that had served over 30 years to the anti-poaching unit of the South African Army. He shared with us some of his experience and we learned a thing or two about how rhinos communicate… I promise you, that you will not find Fake News in this Rhino Social Network…
Like other territorial species, rhinos communicate their presence by marking their territory. For this purpose, Rhinoceros use middens that can be located as close as few hundred meters from one another.
For instance, a dominant male will use the midden to mark its territory. If another male is visiting the territory and does not want to challenge the dominant male, it will leave its mark outside the edge of the midden to prevent a possible conflict. Using this type of markings offer rhinos a convenient way to keep intruders at bay.
Female rhinos, on the other hand, use middens to advertise their reproductive status. Rhino’s dung contains critical concentrations of progestagen or estrogen metabolites that allows them to signal when they are in estrus or if they are pregnant.
Rhino middens are quite popular and they are used by either black or white rhinos. Despite their names, black and white rhinos are both grey, but they are different in many ways. Being a grazer, the white rhino has a particularly wide mouth with very muscular lips that it uses for gripping and tearing grass. As a result, the white rhino’s dung is made mostly of poorly digested grass. The black rhino however, is a browser. It has a prehensile, pointed lip which he uses to eat the leaves of small spiky trees. Because of the way they grind their feed, black rhino’s dung has twigs which are curiously cut in a 45 degree angle.
To our surprise, while inspecting one of the white rhino middens, we found traces of a visitor black rhino!!! To give you an idea of how rare these creatures are, in the area that we were visiting, they had not seen a black rhino in seven years!
With all the challenges that rhinos face, learning more about their ecology and behaviour can help further our understanding of the species and provide effective means for monitoring populations. Researchers from the University of KwaZulu-Natal in South Africa conducted an experiment where they analysed the chemical makeup of over 200 rhinos' dung and found that that feces of various ages and sexes—such as young animals, dominant males, and females in estrus— carry different chemical cues.[1]
To understand how rhinos react to these hidden messages, they deposited into the middens “Faux Feces” made with grass and mud and sprayed it with the same compounds found in the group’s dung. To their surprise, rhinos reacted strongly to the smell of females in estrus, sniffing around and spending more time in the midden.
The study shows interesting facts about how rhinos respond to chemicals in the dung. From discouraging animals from dangerous areas to supporting breeding programs, learning about the ecology of rhinos markings could provide an inexpensive opportunity to protect the species.
To learn more about Rhino Conservation, please visit Save The Rhino.
[1] Marneweck Courtney, Jürgens Andreas and Shrader Adrian M. Dung odours signal sex, age, territorial and oestrous state in white rhinos284Proc. R. Soc. B
http://doi.org/10.1098/rspb.2016.2376
Σχόλια