i would say it is a count and mass noun. my source (oxford dictionary) said "Nouns can be either countable or uncountable. Countable nouns (or count nouns) are those that refer to something that can be counted. Uncountable nouns (or mass nouns) do not typically refer to things that can be counted and so they do not regularly have a plural form."
The stanza begins with a physical description of the squirrel. The squirrel is grey coloured and therefore the poet says that he wears “an overcoat of gray,” his tail is twisted like a question mark.
