Animals is a neutral term, so there is no opposite. English is mostly a neutral-gendered language. However, specific animals often have male and female terms, and a different term for the young.
Examples:
Consider the bovine species. The male is a bull, a female that has given birth is a cow, a female that hasn't given birth is a heifer, and the young are calves (with a single one being a calf).
Deer are divided into bucks (male) and does (female).
Chickens are divided into roosters (male) and hens (female). The young are chicks or biddies.
sew
sow
Pig or hog.
See
The boar is a male pig; the female is called a sow
Sow IS female/feminine. The male pig/swine is a boar.
female
The sow is a female pig and a boar is the male.
There is no such thing. Pig is a word that describes an omnivorous mammal with a stout body, cloven hooves on each foot and a broad cylindrical snout, it does not describe the sex or gender of an animal.However, the male gender of a pig is a boar (intact male) or a barrow (castrated male), and the female is a sow(mature female) or gilt (immature female).
sow
The opposite of he-bear would be 'she-bear' - but neither is necessarily correct. I think it should be male bear and sow.
The sow.
Sow