2 Brown coat

My teacher said the original mammal coat color was brown.

The books had pictures of brown mammoths, brown early dogs, brown early horses. How would they know what color their hair was?

Someone asked the teacher. He said that most wild animals were brown.

Where he came from, that might be true.

Moose are brown - they blend in with the WET ground around lakes where they feed. Buffalo (American Bison) are brown. Wolverines are brown.

But out in the grass or brush lands, deer are tan colored, rabbits are tan colored (actually it's agouti color which is a mixture of different colors on some hairs, and a peppering in of other colored hairs).

Look at a coyote or wolf, or rabbit, they aren't a chocolate brown.

And the default color of cats is clearly tabby (striped). Even lion cubs are spotted when they are young. And the tabby pattern reappears on the orange tabby and can't be removed.

What is the default color pattern in dogs?
Black & Tan - then agouti overlayed?
Agouti then with a black & tan (tuxedo) pattern overlay?