By Samuel Marthinus Ferreira, Michael ’t Sas-Rolfes, Dave Balfour, Christopher Barichievy, Geoffery Chege, Catherine Newland Dean, Naomi Doak, Holly Dublin, Raoul du Toit, Sue Elliswildt, Richard Emslie, Jacques Flamand, Michelle Erin Gadd, Jamie Gaymer, Markus Servaas Hofmeyr, Michael Harrison Knight, Yoshan Moodley, Joanne Aileen Shaw, Lars Versteege, Lucy Vigne, Friederike von Houwald, Simson Uri-Khob, and Keitumetse Mosweu.
Read the response discussed in this Plain Language Summary here.
Read Oscar E. Wilson et. al.’s reply to Samuel Marthinus Ferreira et. al.’s response here.
Rhinos use their horns in many ways. Rhinos rub horns on objects like rocks or trees, dig up roots, fight with other rhinos or fend off lions that are trying to catch rhino calves. Horns grow all the time, like fingernails, and look the way they do because of the many different things that rhinos do with them in places from deserts to wet savannahs with lots of trees. Despite the apparent importance of rhino horns, a recent study concluded that the size horns got smaller over time.
The study used 80 photos, mostly taken in zoos, of four rhino species. However, the many ways in which rhinos use their horns makes it problematic to use a sample of mostly zoo animals to conclude that wild rhino horn sizes got smaller over time. In addition, the study linked that shrinking to hunting and poaching, which is also a conclusion that we should not draw from a study of captive animals. Even so, poaching for horn remains the key threat to rhinos. Public debate, science evidence, policy making, and management should focus on the causal reasons for poaching and horn trafficking to make and implement plans to reduce rhino crimes.
Relational Thinking 