Black rat
Rattus rattus
Nikita Tiunov · Ozurgeti, Guria Georgia field photo
Key facts in one look
- Size
- Body 15–22 cm, 130–300 g
- Diet
- Omnivore, mostly plants
- Status in Georgia
- Native, widespread
- Habitat
- Forests, orchards, buildings, up to 1,500 m
- Family
- Muridae
- Conservation
- LC / LC
The black rat (Rattus rattus) is smaller than the brown rat, but its tail is longer than its body and it climbs trees well. In the Caucasus it is an old part of nature: the populations of the Black Sea coast and Transcaucasia are considered a Pleistocene relict. In Georgia it has been found from Gagra and Sokhumi to Batumi and Khulo, in Tbilisi, Mtskheta, Telavi and Lagodekhi. In the wild it chooses forests, orchards and scrub; in houses, upper floors and attics. Do not trust the name: the black rat is often brown.
Identification
Black rat: how to identify it
A medium-sized, lithe rat with a narrow muzzle, large rounded ears and a tail longer than its body. The colour varies from black to light brown. It is most easily confused with the brown rat.
An adult's body is 15–22 cm long and weighs 130–300 g. The tail is usually longer than the body, up to 28.8 cm. Southern forms are larger and paler than northern ones.
There are two colour types. Some have a dark or blackish-brown back with a greenish metallic sheen and a grey belly. Others look like a brown rat, but paler and more yellowish, with a whitish belly. The scaly tail is the same colour above and below.
The brown rat has a broad muzzle, small ears and a tail shorter than its body. In the black rat, the long tail and large ears are a more reliable sign than the colour. Do not catch the animal; a photo is enough to identify it.
Colour
Swatches are illustrative. Do not identify a species by colour alone.
Often confused with
An animal of warm climates. In the wild it lives year-round only where the climate is mild, such as the Caucasian Black Sea coast. In Transcaucasia it lives in forests, orchards and scrub up to 1,500 m. It depends on water less than the brown rat does. It rarely digs burrows: it lives in tree hollows or builds round nests of twigs in trees, much like a magpie's nest. In houses it keeps to upper floors and attics and is rare in sewers. In Georgia it has been found in Gagra, Sokhumi, Ochamchire, Poti, Kobuleti, Batumi, Khelvachauri and Khulo, in Baghdati and Tsageri, Mestia, Tbilisi, Mtskheta, Kaspi and Bolnisi, Telavi and Lagodekhi.
The black rat map combines public iNaturalist observations. Regions are taken from the records-by-region table, and the status column separates regions with enough records from regions with too few records. Record counts reflect observation effort rather than population density. Records are still too few to mark any region.
Data: Reptiles.ge + iNaturalist · Methodology
- Field observation
- Several records in one spot
- Photo record
- Region with records
In the wild it eats mostly plant food: seeds, nuts and fruit. Invertebrates play a small part. On ships and in buildings it eats the same as people. It takes about 15 g of food and 15 ml of water a day. It eats a wide range of crops, so farmers treat it as a pest.
It is active mainly at night. It climbs very well and in the wild often lives half in the trees, but rarely swims. It lives in groups dominated by one male. It is less aggressive than the brown rat: in danger it runs, and uses its teeth only when caught. It breeds more slowly than the brown rat. A female has up to 5 litters a year, but in the wild it does not breed in winter, so there are 2–3. A litter holds 2–11 young, and breeding peaks in summer and autumn. Gestation lasts 21–29 days; the young are born blind and naked and open their eyes on day 15. In the wild it lives about a year, in captivity up to 4 years.
Globally the black rat is Least Concern (LC, 2021). In Georgia the 2021 national assessment also lists it as Least Concern (LC), with a stable population. Over the last 200 years its range in temperate Europe has shrunk sharply, as the brown rat replaces it in buildings. In the wild the two species do not compete. It is a natural part of the ecosystems of the Caucasus and Crimea and is food for predatory mammals, birds of prey and owls.
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Yes, and widely. It has been found on the Black Sea coast from Gagra to Batumi, inland as far as Khulo, in Tbilisi, Mtskheta, Telavi and Lagodekhi. On the Caucasian Black Sea coast it lives in the wild all year, and in Transcaucasia in forests and orchards up to 1,500 m. The local populations are considered a Pleistocene relict, not an introduction by people.
Not always. Some have a dark, almost black back with a greenish sheen; others look like a brown rat, only paler and more yellowish. Black animals also turn up, rarely, among brown rats. So look at the tail and ears instead of the colour: the black rat has a tail longer than its body and large ears.
It does not attack and rarely bites unless caught. It does carry disease: it historically spread plague and today carries leptospirosis and other infections. Disease passes through bites, scratches, urine, droppings and fleas. So do not touch it with your hands, and see a doctor after a bite.
On upper floors and in attics. The brown rat does the opposite and chooses basements and lower floors, so the two species keep apart in the same building. The black rat climbs well and easily gets up along branches or walls. It once lived in thatched roofs too, which is why it is also called the roof rat.
References
What this profile is based on
Species profiles are compiled from peer-reviewed literature and established biodiversity databases, and are reviewed as new taxonomic and conservation data become available.
Prepared by the Reptiles.ge editorial team from the sources listed here.
