Data Deficient animals

DD · IUCN Red List data, updated August 9, 2026

789 of the 6036 mammal species mapped on Animal World Map are listed as Data Deficient on the IUCN Red List — 13% of the dataset. They are recorded across 7 continents, most of them in Asia.

There is not enough information to judge the risk of extinction, usually because the species is rarely seen or has never been surveyed. It is not a reassuring category: several species were Data Deficient right up to the point they were found to be Critically Endangered.

Where Data Deficient sits on the scale

Data Deficient has no position on the scale above — it records the absence of an assessment, not a degree of risk.

Data Deficient species by continent

A species is counted on every continent where its Red List range description places it, so a wide-ranging animal appears more than once. The totals below therefore add up to more than 789.

How many are left

Population estimates are quoted as the assessments word them, hedges included. Most species in this category have no reliable count at all, and the ones that do are usually stated as a bound rather than a figure — which is why they are not turned into a ranking here.

Ammodile Ammodillus imbellis
Unknown. No reliable population estimates exist; trend is undetermined.
Armenian Shrew Crocidura armenica
No reliable population estimate exists.
Asia Minor Spiny Mouse Acomys cilicicus
Unknown; no reliable population estimate exists. Population trend is undetermined due to lack of data.
Black Flying Squirrel Aeromys tephromelas
Unknown; no reliable global population estimate has been made. Population trend is assumed to be declining in line with the ongoing contraction and degradation of primary forest habitat across Borneo.
Chibchan Water Mouse Chibchanomys trichotis
No reliable population estimate exists due to the rarity of confirmed sightings.
Crete Spiny Mouse Acomys minous
Unknown. No reliable global or regional population estimate has been published, which is the primary reason for its Data Deficient classification. Population trend is also unknown.
Cyprus Spiny Mouse Acomys nesiotes
Unknown; no reliable census data exist. Population trend is undetermined, which is the primary reason for the Data Deficient IUCN listing.
Dhofarian Shrew Crocidura dhofarensis
No reliable population estimate exists.