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By choosing I Accept , you consent to our use of cookies and other tracking technologies. By Katherine J. Reddit Pocket Flipboard Email. Spotted hyena females have a pseudopenis that strongly resembles the penis of males. Delivered Fridays.
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For more newsletters, check out our newsletters page. The Latest. How a simple solution slashed child mortality in rural Kenyan villages By Dylan Matthews. Why Biden has disappointed on immigration By German Lopez. Bright colors or ornaments are often found in species in which males compete for access to numerous females, Hofer says: Think moose antlers or peacock tails.
Since coupled species don't compete as much, "there's less need, evolutionarily speaking, for showing specific sexual traits," says Amiyaal Ilany , a postdoctoral researcher at the University of Pennsylvania. The only physical difference is males are slightly larger, Ilany says. To figure out who's who around hyraxes, use your ears: Males sing to attract females, while females don't sing at all. Females may choose males by listening to their songs—a way for males to show off that doesn't require flashy colors.
Most snakes are difficult to tell apart sexually, Robert Espinoza , a biologist at California State University, Northridge, says via email. A Kama Sutra of Courtship Moves. Females of this species, like this one , are colorful, but the male looks like he just came from a body-painting party scroll down to sixth photo on the right.
Then there are many species that change sex, especially fish. Take the Nassau grouper, which begins life as a female and changes to a male. See " 7 Gender-Altering Animals. All rights reserved. In what possible circumstances would it be advantageous for females to evolve such highly masculinized genitalia?
There are other mammalian females that possess hypertrophied and masculinized genitalia, such as moles and lemurs, but none possess the remarkable structures of the spotted hyena.
Of the four species in the family Hyaenidae — spotted Crocuta crocuta , striped Parahyaena brunnea and brown Hyaena hyaena hyenas, and aardwolves Proteles cristata — only the spotted hyenas have acquired the penile-clitoris. There are a few schools of thought with respect to the evolutionary origins of this remarkable structure.
Hormones called the androgens have always been present in the systems of female spotted hyenas, and these substances are associated with dominance and social status. In addition, testosterone levels in spotted hyena females are as high as those in males, unlike female striped or brown hyenas who are also not socially dominant to their male counterparts. These steroids in adult females make them extremely aggressive, much more so than their male counterparts, despite being of a similar physical size.
A clear advantage for females to be dominant is illustrated in the feeding system of spotted hyenas, which converge on freshly killed prey and eat as a group. This is quite unlike the solitary foraging tactics employed by striped and brown hyenas. Over twenty individuals may be vying for a piece of a kill, so competition is high.
High-ranking females are the first to indulge in a kill, along with their offspring. Low-ranking females and their offspring are next on the list, finally followed by adult males.
There is some merit to this hypothesis, but thinking back to giving birth through a penis a massive biological trade-off makes me wonder if there is another hypothesis that explains the existence of the penile-clitoris. An alternative school of thought behind the existence of the highly masculinized genitalia of the female spotted hyena is that the structure evolved at least partly in a social context.
They realize a higher level of nutrition and reproductive success than subordinates, and they have even been observed to attack lower-ranking females and their offspring.
It would seem, then, that existence of a ritualistic behavior that reiterates social status may be advantageous for high- and low-ranking females, to maintain dominance in the former and to reiterate submissiveness in the latter.
When females greet each other, they stand in a parallel position, facing in opposite directions. It was an attempt to discover how the pseudo penis forms, but the enlarged organ still developed to great lengths even without it. During these ceremonies, both sexes develop phallic erections. A zoo in Japan once spent four years trying to mate a pair of hyenas before realizing they were both males, due to how similar a female pseudo penis is to a real one.
Here's something you don't hear every day. Female spotted hyenas have what's known as a "pseudo penis. The females have higher levels of testosterone than the males.
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