"Badgers' skin" or another type of leather in Exodus 25:5 et al.?

"And this is the offering which ye shall take of them; gold, and silver, and brass, And blue, and purple, and scarlet, and fine linen, and goats' hair, And rams' skins dyed red, and badgers' skins, and shittim wood," (Exodus 25:3-5, KJV)

The charge is that badgers are unclean animals and hence unsuitable for use in the tabernacle (ESV - Leviticus 11:5, Deuteronomy 14:7).  There is no internal inconsistency in the KJV, however, because the KJV does not translate this unclean animal as "badgers".  The KJV translates this unclean animal in Leviticus 11:5 and Deuteronomy 14:7 as "conies".  Therefore "badgers" (at least their skins) are not unclean according to the Bible, whether or not modern Jews regard them as unclean.

The Bible versions are in disagreement about what type of animal is referred to in Exodus 25:5 and elsewhere where תּחשׁ (tachash) is used.
  • KJV: badger
  • NIV 1984: sea cow
  • ESV: goat
  • NASB: porpoise
  • ASV: seal
Some translations avoid the issue and do not mention the name of the animal (e.g. TNIV, NIV 2011).  There is no reason to doubt the KJV translation since it makes just as much sense as any other translation of תּחשׁ.