What is the meaning of "tough little number"
According to longman dict, little number is a dress or suit of woman. But I can't get the meaning of the word "tough" in this phrase.
Here is the context:
https://www.msn.com/en-xl/northamerica/northamerica-life-arts/30-incredible-photos-of-animals-in-the-wild/ss-BBS2Mgv?li=BBKxOg5#image=13
tough OED
As an epithet of commendation: very good, ‘great’. U.S. slang (orig. African-American).
From 1937:
Amer. Speech 12 45/2 I caught Wright's band last night and are they tough.
little number OED
- colloquial. Used generally (and frequently humorously) to refer to any person or thing (identified more precisely by context). Frequently in little number.
In your cited context: a great horse!
Number can also be a person, not an article of clothing.
Collins:
slang, sometimes offensive: a person, esp a woman who's that nice little number?
I could imagine seeing "number" used this way by Archie Goodwin in a Nero Wolfe novel, or by someone in a Raymond Chandler book.
Extending this concept, we get cute individual, which in this case is an attractive horse. This is humorous. It's kind of like writing a photo caption saying, "Wouldn't you like to take this cutie home with you tonight?"
The tough part is because this variety of horse can stand up to the harsh climate in Iceland, according to the source material ("A tough little number: Having arrived with the first Scandinavian settlers, the Icelandic horse is a small, robust species that is particularly well adapted to the Icelandic climate. Good thing, because in Iceland, the horses stay outside all year round!")