how many mammals are there?

Question: how many mammals are there?
- Keywords:
  mammal
Asked by Hasafan to Áine, Ciarán, Eoin, Lydia, Victoria on 19 Nov 2014.
- Lydia Bach answered on 19 Nov 2014:
  
  Hey Hasafan,
  
  there are around 5 500 mammal species (5 416 to be exact), but we are still finding new species of mammals in remote parts of the world! Like this tiny elephant shrew:
  
  http://www.livescience.com/46570-tiny-elephant-shrew-discovered.html

Question: how many mammals are there?