Secondary Sexual Characteristics, also known as sexual dimorphism, are elements of a creature's physiology that result from it being male or female. It is one step removed from "primary sexual characteristics" (which describes the actual reproductive organs). For example, everyone knows that only male lions have that iconic mane of fur around their neck, and that only male mallard ducks have a green head; it is one of their species' Secondary Sexual Characteristics.
Many times, fictional creatures are based on some manner of Real Life inspiration, and whether or not they have noticeable sexual dimorphism corresponds to whatever inspired them — if one author decides to call a lion a Smeerp, it makes sense that male Smeerps might have thick manes while female Smeerps do not, right?
Now a full discussion of these characteristics is well beyond the
scope of this wiki; but when this subject arises in fiction, it can manifest itself in a variety of ways.
Secondary Sexual Characteristic Gender Clues
- Animal Facial Hair: Male individuals with moustaches and/or beards.
- Bizarre Sexual Dimorphism: Sexual dimorphism played to such extremes that males and females are scarcely recognizable as members of the same species at all. (Can be the result of Bizarre Alien Biology.)
- Furry Baldness: Older male individuals who are bald or balding.
- Furry Female Mane: Female individuals possess a head of long, humanlike hair that the corresponding males do not. (A common occurrence with anthropomorphic animals.)
- Humanoid Female Animal: Species where members of one sex (typically, the females) are more anthropomorphized than their counterparts.
- Impossible Hourglass Figure: Female individuals possessing wide hips, a narrow waist, and a large bust. (Also common with anthropomorphism.)
- Lantern Jaw of Justice: Or rather, use it as moderation and doesn't always have to be heroic. But either way, males tend to noticeably have larger and more robust jawbones than females.
- Messy Male, Fancy Female: Female individuals appear smooth-furred or feathered or elaborately groomed, whereas male individuals appear scruffy or messy.
- Non-Mammal Mammaries: Species whose female members have humanlike breasts, regardless of whether or not their species has any need for such things (and, frequently, they don't).
- Masculine Lines, Feminine Curves: Females have curvaceous bodies while males have squarer, more angular or straighter bodies.
- Pale Females, Dark Males: Females are lighter colored than males.
- Sexy Dimorphism: When one gender of a non-human species is both anthropomorphized and sexualized, while the other isn't.
Other Gender Clue Tropes
- Pink Girl, Blue Boy: A special case of Color-Coded for Your Convenience.
- Tertiary Sexual Characteristics: Gender clues supplied by means other than the individual's inherent physiology.
Tropes That Get the Secondary Sexual Characteristics of Animals Wrong
Since this is seen a lot in nature, any examples of real-life animals would be redundant. Please only list fictional examples that aren't listed in any of the tropes listed here. Anything that fits in any of the tropes listed should be listed in that trope.
Examples:
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Comic Books
- Green Lantern: The people of Graxos IV essentially look like golden-skinned elves, but the females like Arisia Rrab have much more human-looking feet. Males like her uncle Blish Rrab have only two toes, which are widely spaced and more pointed.
- The Scrameustache: The Galaxians are generally green humanoids with round black noses, but the females have full heads of hair while the otherwise bald males only have antennas (and beards, for the elders).
- Sleepwalker: Several female Sleepwalkers appear both in Sleepwalker's hallucinations and as part of Cobweb's attempt to manipulate Rick into thinking Sleepwalker was evil. Sleepwalker women have bigger hips and hair on their heads. When one letter writer asked why female Sleepwalkers are the only ones with hair, the letter column sarcastically said "because there's no Hair Club For Men in the Mindscape!"
- In Xanadu (Vicky Wyman), the only way to casually differentiate the Dragons of the Golden Realm's sexes is by the color of their hair.
Comic Strips
- In Love Is..., the girl has dots for nipples, unlike the boy.
Fan Works
- Ben 10: Guardians: According to Kevin, male and female Anubian Baskurrs are differentiated by skin color, with females being blue. Also, female Decasauran Rexes have a shorter horn, and female Psycholeopterrans have fur.
Films — Animated
- In Madagascar 3: Europe's Most Wanted, Gia the jaguar has a softer, curvier body and a rounder face than the male big cats such as Alex and Vitaly.
Literature
- Animorphs:
- Male Hork-Bajir have three horns, while females only have two.
- Female Andalites have smaller tail blades than males.
- Curse of the Blight:
- The swamp elves have them in spades. Women have wide hips, breasts, and lighter skin than their male counterparts.
- The sama lack them. They are all waifish, lithe, and have little to discern their genders.
- Homecoming has examples for both of Trycanta's non-human races (plus of course the standard ones for the humans).
- Among the lyrror (sapient cats), males have solid-color coats and five toes on their back paws while females have striped or spotted coats and four toes.
- Among the mazor (essentially dragons), females have a different color of scales around their face than on the rest of the head while males have only one color of scale and their wings are further apart.
- In Stielauge Der Urkrebs, the female trilobite is described as being much more slender and elegant than the more robust protagonist Stielauge.
Live-Action TV
- In Dinosaur Planet, male Protoceratops are shown with larger square-shaped frills and prominent nasal ridges, as well as more striking color contrast between the golden-orange frill spots and their gray-brown bodies.
- Walking with Dinosaurs has a few examples. For instance:
- Female T. rexes are portrayed as being larger and more aggressive than their male counterparts. Do note that there's very little support for this nowadays.
- Female Ornithocheirus are depicted as lacking the keel-like crests that the males have on their beaks, while female Tapejaras have smaller head crests than their male counterparts.
Video Games
- Monsieur Scarlet is the only male ant in Bug Fables and the only one with wings; in real life, only male and infertile queen ants have them.
- In The Eternal Cylinder, male Onkifurt have a dark pattern on their bills that females lack. So far, Onkifurts are the only animals in the game to display sexual dimorphism.
- Monster Hunter: Some monsters have at least one secondary sexual characteristics that sets them apart from their opposite gender counterparts. Those differences are sometimes different enough that they are considered a seperate species altogether as is the case with monster pairs like Teostra and Lunastra.
- Aside from their different colour palettes, the Rathian is distinguished from her male counterpart, the Rathalos by having a more enlongated chin spike in comparison. Supplementary materials also suggest the longer spike is used as an apparatus to help the Rathian feed her youngs.
- The Black Diablos is considered a subspecies, but is actually a normal female Diablos in heat. When in a mating season, her body colour changes from tan to black, which serves as a visual warning to hunters and other monsters as they tend to be extremely aggressive.
- While not shown proper in gameplay as they cannot be hunted, the female Mizutsunes are said to look more dull and streamlined compared to their male counterparts, who have brighter and fluffier bodies which aid them in attracting mates not unlike a peacock in real life.
- Narwha carries a golden sac which her male counterpart Ibushi lacks. It also serves as a large glowing weak spot which hunters can wallop when she gets stunned.
- The female playable characters in Nululu Online have a ball-shaped body and a ponytail or tail, while the males are mostly round with a pointed tip on their backs. The female Kiku also have two pigtails instead of one.
- In the Plants vs. Zombies franchise, starting from PvZ 2's Big Wave Beach update and onward, the zombie species' established form of sexual dimorphism is based on the look of their hair, with female zombies consistently having longer, more complex, and more feminine hair (or hairlike substitutes in Neptuna's case) in contrast to the male zombie's more masculine (though often, lack thereof) hairstyles.
- Starting in Pokémon Diamond and Pearl, the Pokémon series had introduced secondary sexual characteristics for certain Pokémon. Some, like the Frillish family and possibly the Gible family, fall into a subtrope, but others, such as Pokémon like Rhydon having larger horns when male, female Pikachu having heart-shaped tails, or female Combee having a red mark on one of their heads, are just this trope.
- In Splatoon, Inkling and Octoling girls in their humanoid forms have smaller eyebrows and slightly curvier bodies than boys. Also, female Inklings have longer tentacles than the males, just like real squids.
Web Animation
- Dinosauria mostly goes with the theory that males (particularly among the predator species) were smaller and had other distinguishing features to show off to mates/rivals than the females:
- "A More Ancient Spring"; besides the obvious dimorphism in the male Lambeosaurus having a more prominent head crest than his potential mates, the male Gorgosaurus from the same short is smaller and more darkly colored than the female he pursues.
- "Sea and Sky"; the Alpha Male Geosternbergia is physically larger, has brighter colors, and a more pronounced head crest than his harem.
- "The Last Tyrant", the male T. rex is shown to be slightly smaller and leaner than the bulky female and has more prominent brow ridges.
- The male Kronosaurus from "Monsters Down Under" has yellow eyes and green scales around them, while the female has blue eyes and white scales. Their calf has green scales around the eyes, indicating that it too is male.
- In Helluva Boss, male-assigned imps have white hair and equally-sized black and white stripes on their horns, while female-assigned imps have black hair and black horns with very thin white stripes. Millie's sister Sallie May has male-type horns and white roots showing, and is confirmed to be a trans woman like her voice actress; a couple of similarly denoted trans imps can be seen during Beelzebub and Verosika's parties and Chaz's funeral, and another is present in the sister show's second episode.
- In Symbolics, the male symbolics, known as hieroes, will have wide and flat torsos, lack eyelashes and have eyebrows for some, while females, the glyphers have slimmer torsos and have eyelashes.
Web Original
- Serina:
- Male woodcrafters are twice the size of the females and have red manes, more detailed facial markings, and more robust ears.
- Male royal villaingulls develop a golden triangular point on the top of their beak reminiscent of a crown for display.
- Male crowned imphounds can be distinguished by both their brighter facial and gular colorations and larger horns.
- Male prancelopes have larger and more curved reddish horns compared to the female's shorter, drabber, and more daggerlike ones.
- Male stupendous mothmites are very vibrant in comparison to the drabber females.
- Apart from being three times larger than females, male great golden squaboons have the golden feathers that give them their species name and larger, more elaborate facial markings and fleshy "horn" crests.
- Male dancing dunces gain blue coats and a red beak and dewlap upon reaching sexual maturity.
- Male spoonbilled soggobblers gain a red bill during the mating season.
Western Animation
- The adult dogs in Bluey (2018) have some small differences for this. Males tend to have thicker muzzles and wider bodies then the females. Adult male dogs somewhat tend to have rounder pupils while the adult females and children (regardless of gender) have elongated pupils.
- My Little Pony: Friendship Is Magic:
- Mares (female ponies) tend to have rounded muzzles and eyelashes, while stallions (males) tend to have angular muzzles and no eyelashes.
- Male hippogriffs have larger beaks than females.
- According to Word of God, the only way to tell male and female kirin apart is that females have eyelashes.