About those rhino horns. They are made of keratin, just like a fingernail.
DEMAND: Mostly from China and Vietnam, where for centuries people think they cure everything from cancer to snake bites to hangovers. Medical science says it’s as much of a “cure” as biting your fingernails. Demand is akin to drugs – there is no end to the demand, particularly when someone is convinced it will save their life.  They are also a status symbol in Asia, put on a pedestal.
SUPPLY: 70% of rhinos live in South Africa. Poaching is a huge problem, because the intense demand drives up the end user price so it is as expensive as gold. Rhino poaching kills the rhino by damaging the facial tissue to get the horn. South Africa has APU (Anti-Poaching Units) who wear flak jackets, are heavily armed and sleep in the bush to protect rhinos. Reportedly, poaching is often an inside job, with the APU in on the profits. Per National Geographic, the police are frequently in on the take, so reporting poaching is also problematic. Our guide said he’s found several poached rhinos at Kruger, one with “sorry” written on the carcass in polenta. The people who poach are very, very poor.

Some people are trying to solve the problem a different way. Some rhinos are owned by farmers, who sustainably “harvest” (like trimming a nail) a rhino horn, which regrows every 2 years. Apparently if you retain a base of three inches, the rhino is fine. There is one farmer who harvested 245 rhino horns over several years (which are kept in a bank vault). He tried to auction them off to online buyers in Aug 2017, thinking he’d make big money, flood the market and quash the demand for horns, turning the market upside down. However, there is a law that rhino horns are not allowed to leave South Africa, so anyone who purchased them couldn’t transport them.

Long story short – it’s way more complicated than I thought.