A subcategory of Tertiary Sexual Characteristics and Long Hair Is Feminine, this is when female anthropomorphic animals have human-like heads of hair while their male counterparts do not. So while males are free to have what looks like a "bald" head (or at most, tufts of fur on their head indicating hair), females must have a more "obvious" indicator of their gender (the other option would be hiding the perceived "baldness" with hair accessories à la Minnie Mouse).
Non-mammal examples overlap with Non-Mammalian Hair.
Is the little sister trope to Non-Mammal Mammaries and a subtrope of Humanoid Female Animal.
The female characters in Marvel Comics' Animal Superhero series Peter Porker The Spectacular Spider-Ham, such as Mary-Jane Waterbuffalo and the Scarlet Pooch, all have long hair, in a different shade to their fur. Peter himself has the brown hair of his human counterpart, but is otherwise furless, being a pig. And Nick Furry, Agent of S.H.E.E.P., somehow has stubble growing over his fur.
In Albedo Erma Felna EDF, the Felna family, who are cats, has the rare genetic trait of the female members having thick human like head hair.
The majority of the mice (whether male or female) however, don't have human-like head hair, though Dr. Dawson does have a moustasche.
Inverted in The Jungle Book where Hathi Jr, a male baby elephant has human hair on his head. Played straight with his mother Winifred in the show Jungle Cubs where she is shown as a calf as with her eventual husband Colonel Hathi, however.
The Lion King takes advantage of real hyenas neck manes to make more evident that Shenzi is female. While the three of them have manes◊, Shenzi's is the only one that does not thin when reaching the head but becomes longer and falls over its eyes. It's on the other hand inverted with the lions, obviously.
Averted in Flushed Away. Rita, a female mouse, has red hair on her head. Roddy, a male mouse, also has a full head of brown hair on his head. And so does every other mammal character in the movie, except for those who are meant to be... er... 'bald', like Whitey the lab rat.
Rare non-animal example: Cars actually both inverts this, averts this, and plays this straight, where many of the vehicles in the film lack any "hair", except for Luigi and his Uncle Topolino, who have vinyl toupees; Professor Z who has damaged wiring on his roof resembling a bald head; Rastacarian, who has black wiring on his roof resembling dreadlocks; and Signora Bernoulli, who has black wiring hiding under her scarf.
In Once Upon a Forest Abigail has hair, but so does just about every mouse character, even males. The rest of the main characters don't have it.
A variation in 9. Number 7 has a feather sticking out of her helmet that is meant to resemble a ponytail.
In Donkey Kong Country, all of the female Kongs (Dixie Kong, Candy Kong, Tiny Kong, and Wrinkly Kong) all have human-like hair on their heads; indeed, Dixie and Tiny even glide and attack with Prehensile Hair. Swanky Kong sort of does as well, but he'd be the only male Kong with hair.
Most female characters on Sabrina Online. The eponymous skunk has short white hair, her kid sister Tabitha has white pigtails, Amy has long blonde hair, Zig Zag has long silver hair, etc. Sabrina's boyfriend R.C. also has hair.
Played straight throughout Kevin & Kell, except for lions: Males have the large mane; females have no additional cranial hair.
Played straight with Minerva Mink, who has human-like head hair.
Slight example with the Warner kids. Yakko and Wakko (when his hat is off) look bald and qve normal cheek tufts. Dot, however, has tufts of fur on the sides of her head that looks Ike a pixie cut.
In the TV series of Brian Jacques' Redwall novels, Rose in the Martin the Warrior arc has a long ponytail, despite human-like hair being avoided or only mildly used in earlier seasons.
All the female characters in Arthur except Fern, while most but not all of the male characters are "bald" (other than the fur). Francine's father is a strange combination - he's has fur and hair, but he's got Male Pattern Baldness leaving just fur on the crown of his head surrounded by hair. (He's a monkey, BTW.)
Petunia Pig from Looney Tunes has a full head of hair, but Porky Pig doesn't.
Lola Bunny in Space Jam has a larger, blonde tuft of hair on her head, but has her ears tied up in a ponytail as a substitute for long hair. Bugs Bunny only has smaller tufts.
Her long-running, print-only predecessor, Honey Bunny, averted the trope. She did sometimes arrange her ears to resemble a hairstyle, though.
Similarly, Melissa Duck has a full head of hair, but Daffy Duck doesn't.
Daisy Duck is occasionally a borderline example, depending on the show:
Her "classic" design averts this trope, although she does have long tufts of feathers on the back of her head.
This makes for hilarity in Disney Party, a game based on Mario Party, where Daisy is rendered in classical style... with her sound when being damaged being "My Hair!"
Quack Pack exaggerates her tufts so that they look like a pixie cut, but they still look very much like "styled" feathers.
House of Mouse Daisy is a pretty straight example, as she has a very long ponytail, though at least it's white like her feathers.
In Lady and the Tramp Lady's ears are designed so they look like loose pigtails. Peg's ears are also drawn to be very long and bushy, along with a mane on top of her head to give the impression of long shaggy hair. The male dogs' ears in the film are drawn much shorter.
Some female characters in DuckTales, like Mrs. Beakly and Magica De Spell, had hair.
Played with in Darkwing Duck: Whilst Morgana, Gosalyn and the other female characters have hair, Drake/Darkwing, Honker and most other males don't. Inverted by Launchpad and Tank, who have hair.
Cleo from Heathcliff and the Catillac Cats had long blonde human hair. The only other cats to have hair on their heads were Wordsworth, who had a lock of longer hair on his forehead, and Hector.
Rare plant example: Many of the female characters from VeggieTales, with the sole exception being Mrs. Asparagus.
Played straight and averted in Sonic Sat AM, Sally and Lupe have a mane of hair, while Bunnie only has a tuft of fur on her forehead. Most male characters have just fur, though Antoine has a blond cut and some elderly characters such as Uncle Chuck and King Acorn have mustaches.
Played with in The Dreamstone, most of the Noops, male or female, have visible hair, but Amberley's mane is definitely more evident than for male characters like Rufus. All the Wuts have manes, though the female Wildit is made divergent for having a different style.
Played straight with Minka, Pepper, and Zoe from Littlest Pet Shop (2012). Averted with Penny, who doesn't even have a tuft, and Buttercream (she has a bow though). Vinnie, a male gecko has hair as well.
Snork Maiden from The Moomins. Though averted with Moominmama who is shown as female by her handbag accessory. This is likely to establish that Snork Maiden isn't related to the family.