At the current poaching rate in South Africa rhino females will not replace themselves this year (2012) and total extinction of Africa’s remaining rhino becomes probable in less than ten years.
My husband is a numbers guy. I asked him to play with some of the figures surrounding the plight of Africa’s rhino and how illegal trafficking is driving this species to extinction.
Our conclusions are purely speculative. In no way do they claim to be scientific, only a means to project the impact of current rhino poaching trends over time. Our information is based on data gleaned from several websites (referenced below.)
According to the World Wildlife Fund there are about 16,000 rhino left in Africa with 93% of them calling South Africa their home.
Apparently more male rhino calves are born than females. However, supposedly the mortality rate of males is higher due to territorial fighting and hunting. As there are no numbers regarding current female populations we simply went with the broad assumption of 50% or 8,000.
We supposed that about 5% of these females die from natural causes each year leaving around 7,600. Of these females around 3,884 may have a calf (a cow is around 7 years old when she has her first, and can have another every three years until around age 30.) Using these assumptions plus that some females will not bear every three years, thus about 971 calves were possibly born in 2011. If half were female and as calf mortality rate is high (according to Save The Rhino) we can questimate that around 242 female calves survived.
Now if we assume that half the rhino poached last year were female that would leave a female population of female rhino at the end of 2011 at roughly 7,620. We can deduct from this that beginning this year (2012) female rhinos will no longer replace themselves.
Or we can look at it like this: The 222 mothers killed in 2011 resulted in the loss of at least 1,100 calves. Using the same mortality, reproduction and poaching calculations that means, that in just four years we lose close to 10,000 young rhino!
In 2008 83 rhino were killed by poachers, a 638% increase from 13 in 2007. In 2009 122 were lost (147%), 333 in 2010 (273%) and an alarming 445 in 2011 (135%).
If we hypothesize that the rhino poaching rate continues unchecked at a 25% increase (assuming the anti-poaching efforts make a difference) the rhino will be extinct by 2022 or in 10 years. Even if all the female calves born in 2012 survived they would barely be old enough to have a calf before that dreadful day!
Now of course there are far too many variables to make any kind of accurate predictions. Plus we hope that the anti-poaching organizations prove successful. Thus please view these assumptions merely as a means to paint a picture of current trends and the trail to the rhinos extinction, if we can’t curb the poaching and stop the illegal trafficking.
Number of rhino left
High mortality rates have limited the successful breeding of black rhinos
More male calves are born than female calves, but male mortality rate is higher, leading to adult sex ratios biased towards females. Fighting is the most common cause of adult male deaths. Most females die of old age