Can't find monkeys in photos on my device

Image search by tag works perfectly in ios 13. I can find anything I want: cars, doors, children, people, windows, dogs, cats, trees, etc... Perfectly, except monkeys. Why ios can't find monkeys? But! It works, when I use tag "animals" for search. All animals including monkeys are shown.

But it doesn't work with strictly "monkey" request =/