Black Rat

## Description

The Black rat (otherwise called the Ship rat) has a hairless and extremely long tail that is longer than its head and body. Romans were the ones who introduced this species to Britain. As a matter of fact, the coat of the Black rat varies from black to grey-brown. As compared to Brown rats, these animals have smaller bodies and larger ears and eyes. The Black rats are accomplished climbers. They are capable of running along telephone wires, using their tails to balance while moving. The species is also called 'Roof rat' due to constructing their nests high in roof spaces.

## Distribution

These rats are widely distributed around the globe, occurring on all continents. Black rats are thought to be native Indian and Indo-Malayan species. In course of time, however, they have been introduced to all continents due to human travel. Since these animals are found through human seafaring, they most frequently occur in coastal areas. Black rats adapt to a wide range of habitats. In urban areas, they are found around warehouses, residential buildings, and other human settlements. They are also found in agricultural areas, such as in barns and crop fields. In urban areas, they prefer to live in dry upper levels of buildings, so they are commonly found in wall cavities and false ceilings. In the wild, Black rats live in cliffs, rocks, the ground, and trees. They are great climbers and prefer to live in palms and trees, such as pine trees. Black rats are also found around fences, ponds, riverbanks, streams, and reservoirs.

## Behavior

Black rats are normally nocturnal and tend to forage after sunset. They often meet and forage together in close proximity within and between sexes. They are highly social animals, forming 'packs' - groups of two or more dominant females and several males, one of which is dominant. These females lead the pack and dominate all members of the group. Meanwhile, the dominant male doesn't submit to them and often forms a separate linear male hierarchy. Female rats are considerably more aggressive than males. Black rats can be either arboreal or terricolous, depending on geographical location. They are excellent climbers, due to which those living in urban areas can make their homes high on the upper floors of buildings. Individuals within the pack establish dominance through aggressive threat postures and physical contact. These rats are also very vocal animals: they are known to give out squeaking sounds when threatened or when communicating with conspecifics. They leave oil marks in order to define territorial boundaries. Black rats also have developed senses of vision, hearing, touch, and smell.

## Diet

Black rats are omnivorous animals. They eat a broad range of foods but are highly selective feeders. Their diet consists of vegetation such as fruit, nuts, grain, and cereals, supplemented with invertebrates such as insects.

## Reproduction

Black rats have a polygynous mating system, where a single male mates with a number of females. Usually, the dominant male is the most successful breeder. Black rats mate from March to November. Their nests are typically spherical and made of shredded material, including sticks, leaves, other vegetation, and cloth. In the absence of palms or trees, they can burrow into the ground. The gestation period lasts for 21-29 days, yielding 3-5 litters of 1-16 young (with an average of 7) per year. Babies of this species are born altricial. Their eyes open only at 15 days old, while hairs appear by the end of the nursing period. The young are weaned, gaining independence at 3-4 years old. Females become reproductively mature at 3-5 months old.

## Population

### Threats

The Black rats are killed by people as pests. In addition, these animals are very dangerous to humans. As pests, they are known to consume crops, destroying farms and fruit trees. Furthermore, they simply destroy what they don't eat. The 'Black Death' or bubonic plague, which took millions of human lives in medieval times, was spread by the Black rats. This is largely due to fleas on their body, which carry multiple diseases that are extremely dangerous for humans and livestock.

### Number

According to IUCN, the Black rat is abundant and widespread throughout its range but no overall population estimate is available. However, according to the People’s Trust for Endangered Species resource, Great Britain's population size is around 1,300 individuals, including up to 1,000 individuals on the Shiant Islands, Hebrides. Overall, Black rats’ numbers are stable today, and the species is classified as Least Concern (LC) on the IUCN Red List.

### Ecological niche

The Black rat has a rather negative impact on the local ecosystem: this animal has become the reason for the extinction of numerous birds, small mammals, reptiles, invertebrates as well as plants, particularly on islands.

## Fun Facts

Rats are highly social animals that enjoy the company of both conspecifics and humans. Rat groups are called 'mischiefs'. They are known to engage in group plays and sleep curled up together. Rats are also careful to injured and sick members of the pack. When solitarily, they tend to become depressed, anxious, and stressed.

Rats are very intelligent animals with good memory. They are known to exceed in intelligence rabbits, hamsters, mice, gerbils, and guinea pigs. Learning a direction-finding route, a rat will remember it throughout its life.

In spite of being curious animals, rats are also very shy, typically fleeing from threat instead of facing it.

Rat served as a sign of good luck for the Romans.

These agile animals are colorblind and possess an extremely low vision.

Rats are generally right-handed.

When tickled or dreaming during sleep, these animals occasionally give out a noise, resembling laughter, although it cannot be perceived by the human ear.