You've probably never seen Tarzan’s chameleon, the Seychelles sheath-tailed bat or the pygmy three-toed sloth - and the chances are you never will.
They're amongst the 100 most endangered species in the world, according to a report from the Zoological Society of London (ZSL) and IUCN, the International Union for Conservation of Nature.
Part of the problem, says the team, is that none of the species on the list provides humans with obvious benefits.
"The donor community and conservation movement are leaning increasingly towards a ‘what can nature do for us’ approach, where species and wild habitats are valued and prioritised according to the services they provide for people," says Professor Jonathan Baillie, ZSL’s director of conservation.
"This has made it increasingly difficult for conservationists to protect the most threatened species on the planet. We have an important moral and ethical decision to make: Do these species have a right to survive or do we have a right to drive them to extinction?"
Most of the species on the list have a fighting chance for survival - if they're given enough of a helping hand. But their declines have mainly been caused by humans in the first place.
"All species have a value to nature and thus in turn to humans," says Dr Simon Stuart, who chairs the IUCN Species Survival Commission.
"Although the value of some species may not appear obvious at first, all species in fact contribute in their way to the healthy functioning of the planet."