Shabbos Daf 28a - Sasgona

Based on Likutei Sichos Parshas Trumah vol 31 page135

Concerning the multi-colored  Tachash animal in the Mishkan whose skin was used as a covering for the Mishkan..in the time of Moshe. The Talmud brings Targum Onkelos who describes this animal as a "Sasgona"  - ( sas gavna, ססגונא, ששש ומתפאר בגוונין ) that is  joyous  {she-sas} and glorified in its colors {gavnin}. 

There are various opinions as to whether this animal is a behama or a chai. Rashi, in his commentary on the Chumash  in Parshas Terumah concludes from various opinions that it is a type of  undomesticated animal (chai),  How does Rashi come to this conclusion? Also, Rashi adds to the Targum's translation of the tachash that" it is happy and boasts with its colors that belong to him"-why does Rashi add the words "that belong to him"?

        

Rashi comes not to negate the explanation that the tachash is a type of behama but he does come to negate the idea that the tachash is the name of a dye and that the explanation of the phrase"ohros tachshim" is likened to the phrase "ohros ailim maodomim"-that just like the skins of the rams are dyed red so to there is room to explain that "ohros tachashim" means that the skins of the tachash are dyed with a dye whose name is tachash. 

So Rashi explains that they took skins of animal whose name is tachash and not that they took skins of rams and dyed them with a dye called tachash. This is also connected to why Rashi found it necessary to add to the words of the Targum "that belong to him" - meaning that this emphasizes the character of the tachash that its realization that it has a multicolored skin causes  the tachash to boast because it knows it has his own beautiful colors that it was created with and not that the dye was added on later.

        

This is also the reason why the tachash skins were at the very top covering of the Mishkan. This points out the unique advantage of these skins over the skins of the red-dyed ram skins, not only because the tachash  was multi-colored (and unlike other dyes where each one was brought separately like techakles, argomon, tolas shani, etc) but mainly because the colors were natural to the skin of the animal and not that it was dyed in later .....and to such an extent that the multicolors was a part of the character  of the animal in that it was happy and boasted with its colors that belonged to it.