One of the more peculiar physical features of this species is its external genitalia.
The male fossa has an unusually long penis and baculum (penis bone), reaching to between his forelegs when erect, with an average thickness of 20 mm (0.79 in).
The glans extends about halfway down the shaft and is spiny except at the tip.
In comparison, the glans of felids is short and spiny, while that of viverrids is smooth and long.
The female fossa exhibits transient masculinization, starting at about 1–2 years of age, developing an enlarged, spiny clitoris that resembles a male's penis.
The enlarged clitoris is supported by an os clitoridis, which decreases in size as the animal grows.
The females do not have a pseudo-scrotum, but they do secrete an orange substance that colors their underparts, much like the secretions of males.
Hormone levels (testosterone, androstenedione, dihydrotestosterone) do not seem to play a part in this transient masculinization, as those levels are the same in masculinized juveniles and non-masculinized adults.
It is speculated that the transient masculinization either reduces sexual harassment of juvenile females by adult males, or reduces aggression from territorial females.
While females of other mammal species (such as the spotted hyena) have a pseudo-penis, no other is known to diminish in size as the animal grows.
One of the more peculiar physical features of this species is its external genitalia. The male fossa has an unusually long penis and baculum (penis bone), reaching to between his forelegs when erect, with an average thickness of 20 mm (0.79 in). The glans extends about halfway down the shaft and is spiny except at the tip. In comparison, the glans of felids is short and spiny, while that of viverrids is smooth and long. The female fossa exhibits transient masculinization, starting at about 1–2 years of age, developing an enlarged, spiny clitoris that resembles a male's penis. The enlarged clitoris is supported by an os clitoridis, which decreases in size as the animal grows. The females do not have a pseudo-scrotum, but they do secrete an orange substance that colors their underparts, much like the secretions of males. Hormone levels (testosterone, androstenedione, dihydrotestosterone) do not seem to play a part in this transient masculinization, as those levels are the same in masculinized juveniles and non-masculinized adults. It is speculated that the transient masculinization either reduces sexual harassment of juvenile females by adult males, or reduces aggression from territorial females. While females of other mammal species (such as the spotted hyena) have a pseudo-penis, no other is known to diminish in size as the animal grows.
Fossa (animal)