Table 4. Research effort by IUCN Red List status showing the mean and median number of papers per species published 1995–2010 for each IUCN threat category.
| IUCN Red List Status | Number of species (n = 286) | Number of papers (n = 12,201) | Mean number of papers per species | Median number of papers per species |
| Critically endangered | 7 | 177 | 25 | 26 |
| Endangered | 24 | 1090 | 45 | 17.5 |
| Vulnerable | 37 | 1205 | 33 | 5 |
| Near threatened | 27 | 694 | 26 | 7 |
| Least concern | 163 | 8538 | 52 | 10 |
| Data deficient | 19 | 156 | 8 | 0 |
| Not IUCN listed* | 5 | 335 | 67 | 2 |
| Extinct | 4 | 6 | 1.5 | 1 |
* 5 unlisted felines: domestic cat (Felis catus), Chinese mountain cat (F. bieti), Pantanal cat (Leopardus braccatus), Pampas cat (L. pajeros), Iriomote cat (Prionailurus iriomotensis).