# Bat or bird
The bat or bird is a monster class that appears in NetHack, and is represented by an uppercase B glyph (B). Bats and birds are designated internally by the macro S_BAT.[1]
The class contains the following monsters:[2]

B&nbsp;bat
B&nbsp;giant bat
B&nbsp;raven
B&nbsp;vampire bat
Contents

1 Common traits
2 History
3 Variants

3.1 SLASH'EM
3.2 dNetHack

4 References

Common traits
Bats and birds are neutral animals that are typically hostile towards you with the exception of the standard bat, which may generate as peaceful if you are neutral. Tame bats and birds are capable of consuming meat.
Bats and birds are visible via infravision and capable of flying, and generally move erratically: there is a 1⁄3 chance of the monster moving in a random direction, rather than approaching you.[3] Bats and birds generated in Gehennom have slightly higher speed than normal, possibly a play on the phrase "like a bat [on its way] out of hell".[4]

History
The standard bat appears in Hack121, a variant of Jay Fenlason's Hack, where it uses the b glyph; in PDP-11 Hack and Hack 1.0, it begins using the B glyph. The giant bat and vampire bat first appear in NetHack 3.0.0, while the raven first appears in NetHack 3.3.0.

Variants
SLASH'EM
SLASH'EM introduces several new monsters to the bat or bird monster class:

B&nbsp;rhumbat
B&nbsp;athol
B&nbsp;hellbat
B&nbsp;mongbat
B&nbsp;mobat
B&nbsp;harpy
B&nbsp;byakhee
B&nbsp;nightgaunt
dNetHack
dNetHack adds several new monsters to the monster class:

B parrot
B crow
B battle-bat
B warbat
B chiropteran
B&nbsp;byakhee
The Dreprun stave can be carved into a wooden weapon to ward off bats and birds.

References

↑ include/monsym.h in NetHack 3.6.7, line 42

↑ src/monst.c in NetHack 3.6.7, line 1038

↑ src/monmove.c in NetHack 3.6.7, line 915

↑ src/makemon.c in NetHack 3.6.7, line 1275