# Black rat

r black rat 

Difficulty

1

Attacks

Bite 1d3

r black rat 

Difficulty

1

Attacks

Bite 1d3

Base level

0

Base experience

1

Speed

12

Base AC

7

Base MR

0

Alignment

0 (neutral)

Frequency (by normal means)

0 (Not randomly generated)

Genocidable

Yes

Weight

20

Nutritional value

12

Size

Tiny

Resistances

None

Resistances conveyed

None

A black rat:

 has no hands.

 is an animal.

 is carnivorous.

 is normally generated hostile.

 can be seen through infravision.

Reference

SLASH'EM 0.0.7E7F2/monst.c#line1412

Wikipedia has an article about:
Black rat

A black rat is a rat that appears only in the Rat King's level.  Other than that it cannot be randomly generated, it is identical to the sewer rat.  Possibly it exists so that it will be harder to pick out the pack rats which can steal items on that level, as they are also represented by r.

Origin
Black rats, or rattus rattus, were once the most common rats in Europe.  While still common in warmer areas, in most of their previous habitats they have been displaced by the brown rat (rattus norvegicus), likely represented in Nethack by the sewer rat and/or the giant rat.