A fat white rabbit in the Magical Menagerie transformed itself into a top hat and back again (reminiscent of the Muggle conjuring trick in which the performer pulls a rabbit out of a top hat). It is unclear if this is a magical creature or if it had simply been enchanted to perform this bit of Transfiguration (PA4). Lavender Brown had a young pet rabbit at home, named Binky, which was killed by a fox during her third year (PA8).
Powerfully magical silver-coloured fish from the Indian Ocean, a protected species that in turn is a guardian of seafarers, as the ramora is capable of anchoring ships. It is protected from poaching by international wizarding law (FB).
In the Magical Menagerie was a cage full of black rats which were busy jumping rope with their tails;
the saleswitch implied that they would live longer than a common rat's
three-year lifespan (PA4). Rat Animagi appear to have some ability to
communicate with ordinary rats
(GF1). While living in hiding
in number twelve, Grimmauld Place, Sirius appears to have kept Buckbeak mainly on a diet of dead rats
See entry on Scabbers.
Small, goblin-like/dwarflike creatures, Red Caps love bloodshed, and will attempt to beat to death Muggles lost in dungeons or on battlefields on dark nights. (As red caps can be repelled easily by charms and hexes, Muggles rather than adult wizarding folk face the most danger from them (PA8, FB).)
According to A Field Guide to the Little People (Nancy Arrowsmith with George Moorse, New York: Hill and Wang, 1977):
Some of the most bloodthirsty Scottish elves are the Lowland castle spirits. They are called Red Caps ... and by some accounts are said to live only in castles with a history of violence. Others say they live in all Lowland peel-towers [fortified houses or towers]. It may well be that both accounts are true ... The Red Caps' main occupation is colouring their red caps, which they dye with human blood. They throw boulders on to travellers from their towers, then catch the blood in their caps. As soon as the blood dries and the colour fades, the Red Caps look for new victims. They also foretell disasters by making a loud noise like the beating of flax. The only things that discourage them are crosses, cross-handled swords, and words from the Bible (p. 47).These Red Caps are described as short, old elves with a sturdy build and long grey hair. They are about four feet tall and have red eyes.
Native to the wilds of North America and the Far East,
this extremely rare golden-furred giant ox's blood gives the drinker
immense strength. However, since demand far exceeds supply, Re'em blood
is found on the open market only rarely (FB).
JKR borrowed the idea of the Re'em from ancient writings, although she created her own description of this mysterious beast. From The Truth About Unicorns by James Cross Giblin:
"In the original version, the Hebrew writers referred seven times to a powerful animal called the re'em. One of these references appeared in the description of Joseph.... Not knowing what animal the Hebrews had in mind, the authors of the Septuagint translated re'em as monoceros, the Greek word for unicorn. "There's no reason to believe, however, that the Hebrews thought of the re'em as one-horned. Some later scholars argued that it was probably the African antelop, the oryx. They pointed out that the Arabic word for oryx was the similar rim" (page 41).
The reference to Joseph is from the Biblical book of Deuteronomy: "His Glory is like the firstling of his bullock, and his horns are like the horns of unicorns...." (Deut. 33:17). (Thanks to Pigwideon on the Lexicon Forum for this information)
XXXXX - Romania
A magical three-headed, snake commonly reaching a length of 6 - 7 feet,
coloured livid orange with black banding; native to Burkina Faso,
where several forests are designated as preserves for its sole use. The runespoor is unique among known magical beasts
for producing its eggs through its mouths
Runespoors rarely live to a great age, as each head contains an independent brain serving a different purpose, and they tend to attack each other. The right head is the planner, the middle head is the dreamer, and the left head is the critic. The planner decides where the runespoor goes and what it will do next, although the dreamer's visions often lead to a runespoor remaining stationary for days, lost in its imaginings. The critic, the fangs of which are extremely venomous, hisses continually (and irritably), evaluating the efforts of the planner and the dreamer. Often, the other two heads will gang up on the critic and bite it off; two-headed runespoors are not uncommon.
The runespoor was once a favorite pet of Dark wizards, mostly because of its intimidating appearance. A flourishing black market in runespoor eggs and in the serpents themselves has existed for centuries (FB).
"rune" one of the alternate meanings of this word in English is 'an incantation, a charm, esp. one denoted by magic or cryptic signs; a magic word' [NSOED]