Measures snow leopards (6)
I believe the answer is:
ounces
This clue is a double definition.
'measures' is the first definition.
(ounce is a kind of measure)
'snow leopards' is the second definition.
('ounce' can be a synonym of 'snow leopard')
(Other definitions for ounces that I've seen before include "Light weights in UNESCO" , "Animals" , "Snow leopards - 16 of them in pound" , "There are16 to the pound" , "Big cats and sixteenths of a pound" .)