The Tabernacle was made up of several layers of different types of materials, one of which was made from an animal called a taĥash.  The identity of the taĥash is a matter of great controversy and was never resolved. Some authorities explain that the taĥash is a monodon or narwhal (seen above), a species of whale. Narwhals travel in small groups, especially in northern ocean waters. It can grow to 6 meters in length. Its primary color is light yellow and it is spotted with numerous dark spots, the only cetacean with spots. A twisted tooth, up to 3 m long, grows out of one side of its mouth, to the extent that for many years it was thought to be the horn of the unicorn. It is possible that a group of these creatures approached the Red Sea and were thrown onto the shore or trapped there.
The narwhal’s appearance closely parallels the descriptions here: It is spotted, it has a
single horn on its forehead and the Sages were unable to determine its precise nature: domesticated or nondomesticated; kosher or non-kosher. 
(This image was taken from the English edition of the Koren Talmud Bavli (Steinsaltz Talmud), Tractate Shabbat, daf 28, page 132. To order your copy of the Steinsaltz Talmudclick here, contact your local Jewish bookstore, or e-mail Koren Books at