Laudator Temporis Acti

I'm unqualified to pass judgment on the accuracy of this Old English translation of Rudolph the Rednosed Reindeer (Hrodulf Readnosa Hrandeor). But it starts out inauspiciously, with the following supposedly Latin title:

Incipit gestis Rudolphi rangifer tarandus

translated as

Here begins the deeds of Rudolph, Tundra-Wanderer.

I can't construe the Latin and would suggest either

Incipit canticum de gestis Rudolphi rangiferi tarandi (Here begins a song about the deeds of Rudolph the Reindeer)

or

Incipiunt gesta Rudolphi rangiferi tarandi (Here begin the deeds of Rudolph the Reindeer).

Because I could not find rangifer in my Latin dictionary, I first thought perhaps it was a mistake for ramifer (also not a classical Latin word, but at least intelligible as "branch-bearing" = "antler-bearing"). But I was wrong -- the scientific name of the reindeer is indeed Rangifer tarandus. What the compound rangifer means and where it comes from I don't know. According to Smith and Hall's English-Latin Dictionary s.v. reindeer, rangifer occurs in medieval Latin.

As for tarandus, online texts (without critical apparatus) of Pliny's Natural History (8.52.123-124, tr. John Bostock and H.T. Riley) have the spelling tarandrus:

The tarandrus, too, of the Scythians, changes its colour, but this is the case with none of the animals which are covered with hair, except the lycaon of India, which is said to have a mane on the neck. But with respect to the thos (which is a species of wolf, differing from the common kind in having a larger body and very short legs, leaping with great activity, living by the chase, and never attacking man), it changes its coat, and not its colour, for it is covered with hair in the winter, and goes bare in summer.

The tarandrus is of the size of the ox; its head is larger than that of the stag, and not very unlike it; its horns are branched, its hoofs cloven, and its hair as long as that of the bear. Its proper colour, when it thinks proper to return to it, is like that of the ass. Its hide is of such extreme hardness, that it is used for making breastplates. When it is frightened, this animal reflects the colour of all the trees, shrubs, and flowers, or of the spots in which it is concealed; hence it is that it is so rarely captured. It is wonderful that such various hues should be given to the body, but still more so that it should be given to the hair.

mutat colores et Scytharum tarandrus nec aliud ex iis quae pilo vestiuntur, nisi in Indis lycaon, cui iubata traditur cervix. nam thoes — luporum id genus est procerius longitudine, brevitate crurum dissimile, velox saltu, venatu vivens, innocuum homini — habitum, non colorem, mutant, per hiemes hirti, aestate nudi.

tarandro magnitudo quae bovi est, caput maius cervino nec absimile, cornua ramosa, ungulae bifidae, villus magnitudine ursorum, sed, cum libuit sui coloris esse, asini similis. tergori tanta duritia, ut thoraces ex eo faciant. colorem omnium arborum, fruticum, florum locorumque reddit metuens in quibus latet, ideoque raro capitur. mirum esset habitum corpori tam multiplicem dari, mirabilius est et villo.

The word occurs in Greek as well, with the same confusion of spelling. See Liddell and Scott, s.v. τάρανδος:

a horned beast, native of Scythia,

A. reindeer, or more prob. elk, Arist.Mir.832b8, Fr.371, Thphr.Fr.172.1, Ael.NA 2.16; τάρανδρος is better attested in Ph.1.384, and is v.l. in Arist. Mir.l.c.; so tarandrus in Plin.HN8.123,124 (parandrum in Solin. 25.30).

Some think Caesar was referring to the reindeer in this passage from his Gallic Wars (6.26, tr. W.A. McDevitte and W.S. Bohn):

There is an ox of the shape of a stag, between whose ears a horn rises from the middle of the forehead, higher and straighter than those horns which are known to us. From the top of this, branches, like palms, stretch out a considerable distance. The shape of the female and of the male is the same; the appearance and the size of the horns is the same.

est bos cervi figura, cuius a media fronte inter aures unum cornu exsistit excelsius magisque directum his, quae nobis nota sunt, cornibus: ab eius summo sicut palmae ramique late diffunduntur. eadem est feminae marisque natura, eadem forma magnitudoque cornuum.

Caesar (op. cit. 6.21.5) also uses another word sometimes translated as reindeer -- reno or rheno:

And to have had knowledge of a woman before the twentieth year they [the Germans] reckon among the most disgraceful acts; of which matter there is no concealment, because they bathe promiscuously in the rivers and use skins or small cloaks of deer's hides, a large portion of the body being in consequence naked.

intra annum vero vicesimum feminae notitiam habuisse in turpissimis habent rebus; cuius rei nulla est occultatio, quod et promiscue in fluminibus perluuntur et pellibus aut parvis renonum tegimentis utuntur magna corporis parte nuda.

But Lewis and Short say the meaning is reindeer skin, not reindeer:

rēno or rhēno , ōnis, m. [Celtic] , a reindeer-skin, as a garment of the ancient Germans, a fur pelisse: renones sunt velamina umerorum et pectoris usque ad umbilicum atque intortis villis adeo hispida, ut imbrem respuant, Isid. Orig. 19, 23, 4 : (Germani) pellibus aut parvis rhenonum tegimentis utuntur (i. e. rhenonibus quae sunt parva tegimenta), Caes. B. G. 6, 21 fin. (v. Kraner ad h. l.); cf.: Germani intectum renonibus corpus tegunt, Sall. H. Fragm. ap. Isid. l. l.; cf. also Serv. Verg. G. 3, 383. --Acc. to Varr. L. L. 5, § 167 Müll., a Gallic dress: sagum reno Gallica (vestimenta).