Rhinos are one among the oldest species of mammals, and also the biggest after elephants, are simply living fossils now. They were once freely roaming across the African savannas and the Asian tropical forests, but nowadays, only a very few rhinos survive outside their highly protected habitats like national parks and forest reserves. 
The major reason is that a pound of rhino horns costs more than $30,000 in black markets. It is an irresistible appeal for the poachers to simply slaughter these poor animals just to cut off the horn. Thousands of rhinos used to be killed each in Africa and Asia for this purpose.
Rhino horn is used in some traditional Chinese medications. The horn is also known effective in curing many medical conditions ranging from nausea to even snakebite. Some of the medicinal usages of rhino horn date back to more than 2000 years.
People in Vietnam say that the horns of these animals can cure a hangover and cancer etc. Horns are also used largely to make jewelry and the “ivory horn” is considered to be as a rare and previous piece. However, there are strict restrictions and regulations now in terms of poaching rhinos for horn, and many initiatives are running across the globe to save poor rhinos from this misfortune.
Making rhino horn in laboratories
Researches are ongoing to make real rhino horns in labs. Pembient is a famous bioengineering firm in Seattle, which experiments with advance DNA synthesis and genomic sequencing to make real rhino horn in the lab. Scientists here use yeast combined with genes to produce elements of rhino keratin, which is the protein component in rhino horn. You can also find a slightly higher version of the same keratin in human hair and nail.
On extracting keratin from yeast, scientists mix it with the rhino DNA, which ensures a genetic signature to the final product. Studies are also going to grow or simply 3D print the rhino horns to flood the black market with it and thereby eliminating the benefits of killing a two-ton animal just for the sake of a 2 to the 3-pound horn.