Why do lion, tiger, panther, and leopard have female forms (lioness, tigress, pantheress, leopardess), but jaguar, puma, cheetah, and cougar don't?
Lion, tiger, panther, and leopard have female forms: lioness, tigress, pantheress, leopardess, but jaguar, puma, cheetah, and cougar don't.
Jagress? Pumess? Cheetess? Cougress? Those aren't words.
Is there any explanation as to why those two sets are different?
Mostly because -ess was not productive in English for animals, only for humans. The OED says (s.v. -ess): "In English the suffix is not used to form feminines of names of animals: lioness, tigress being adoptions from French".
This is not entirely correct: its own account of the etymology of pantheress and leopardess does not mention a French origin; but it is clearly mostly true.
The other point, connected with this, is to do with the age of the word in English. All the words which have an -ess form were in English before 1400, and apart from pantheress, their feminine forms were recorded by 1611.
According to the OED:
- Lion: c825 Lioness: 1300s
- Tiger: c1000 Tigress: 1611
- Leopard: c1330 Leopardess: 1567
- Panther: (OE) Pantheress: 1831
In contrast:
- Jaguar: 1604
- Cougar: 1774