Two subspecies of rhinoceros have been declared extinct this month, highlighting the problem of poachers who kill the beasts only for their horns. The West African black rhino was officially wiped out as it has not been spotted in the wild since 2006, and none live in capitvity. The Javan rhinoceros of Vietnam was declared extinct just a few weeks earlier.

Internet users were wowed earlier this week by dramatic footage (show below) of a black rhino being airlifted to a new home by a military helicopter, but that was a South-central African rhino, which is a different subspecies that is also endangered. The pursuit of rhino horn — which is prized for its supposed medical value and as ornamental trophies — has decimated populations and reportedly pushed the price per ounce above gold in some places. The killing of rhinos is outlawed, which unfortunately makes the horns even more valuable.

There's no scientific evidence to back up widely-believed claims that powdered rhino horn can cure disease like cancer and male fertility problems. According to Convention on International Trade in Endangered Species, more 330 have been killed this year and only a few thousand remain on the continent of Africa.