| Conservation status |
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| Extinct |
| Threatened |
| Lower Risk |
| Other categories |
| Related topics |
 Comparison ofRed List classes above andNatureServe status below  |
Adata deficient (DD)species is one which has beencategorized by theInternational Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment ofconservation.
DD species may have been extensively studied, but in some cases little or no information is available on theabundance anddistribution of the species. It can also indicate uncertainty about the taxonomic classification of an organism; for example, the IUCN classifies theorca as "data deficient" because of the likelihood that two or moretypes of the whale are separate species.[1]
The IUCN recommends that care be taken to avoid classing species as "data deficient" when the absence of records may indicate dangerously low abundance: "If the range of a taxon is suspected to be relatively circumscribed, if a considerable period of time has elapsed since the last record of the taxon, threatened status may well be justified"[2] (see alsoprecautionary principle).
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1 Pre-2001 categories and subcategories shown initalics. | |||||||||||||||||||
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