It is not always sufficient to check whether an animal urinates inwards or outwards to determine the sex. You will also not always find the sex chromosomes XX or XY. What reveals the sex is the kind of gametes the animal produces. If it lays eggs, it is a female. If it makes sperm, it’s a male. Plain and simple, but still not… Some animals produce one type of gamete at the start of life, and another type later. Others produce both eggs and sperm at the same time. Also, there are animals that produce eggs but look and behave as males. And animals that produce sperm but look and act like females. Here are some of the animals with alternative gender solutions: Clownfish The film “Mission Nemo” is about the clownfish Marlin who is looking for his son. But it could just as easily have been about Marlin who changes gender because his wife dies. Clownfish couples have strict gender roles. The largest female looks after the eggs. The male makes sure that no unauthorized person moves into the anemone. Photo: Nhobgood – Nick Hobgood/CC Once a pair of clownfish have found each other, they stay together for the rest of their lives in the anemone where they have chosen to settle. There is often a shoal of small males living with them, but it is this one pair who are the bosses of the anemone and the only ones to have offspring here. But if the female goes missing, the house rules change drastically. The boss male starts behaving like a female fish. His brain then changes to resemble a female fish brain, and after a while he also produces eggs. He will be the anemone’s new chief dog. The largest of the small males rises through the ranks and becomes the new chief male. Blue steelhead and redbill Gender change and power also belong together in blue steelhead and redbill. And the combination is so original that “Game of Thrones” has a lot to learn. The sexes of bluegill and redbill are so different that people long thought they were two different species. MARIOGUTI / GETTY IMAGES/ISTOCKPHOTO / MIRGOLTH / CC BY 3.0 This fish usually starts life as a female, redbill. In the summer, the females live in small harems guarded by a male, the blue steelhead. Harmony prevails, until the male dies. Then the females start fighting. The winner changes gender and becomes the harem’s new blue steel. And then the extra twist in the plot: some individuals are born as males who look like females. They also live in the harem. Presumably the blue steel accepts it because he thinks they are females. What he doesn’t know is that these males most likely fertilize some of his females’ eggs when he has his dorsal fin. Brushshank and brushhen In brushshanks, huge feathered collars are really “hot” when they gather to play in the spring. But a few males mean “not”. They drop the collar and instead look like brats. In the spring, most brush males get impressive collars, while the females go for a slightly more boring style. MIKE LANE / GETTY IMAGES/ISTOCKPHOTO At play, the males with collars perform a dance to chase away other males and impress the brush hens. The hens flock around the one they like best. The collarless males, on the other hand, impress no one. Their strategy is to be so feminine that no male sees them as a threat. And they are so convincing that males try to mate with them. But when the males with collars don’t follow, the feminine males have a blast with the brood hens and thus also get to pass on their genes to the next generation. Bearded dragon With this lizard, it is the weather forecast that determines which gender it will be. And it has three variants to choose from. In beard games, it doesn’t matter if you are a male, a masculine female or a feminine female. All have spiky beards. Photo: André ALLIOT / CC0 1.0 Bearded dragons have sex chromosomes, Z and W. Males have the combination ZZ. Females usually have the combination ZW, but not always. Lizard eggs with male embryos that are exposed to high temperatures also develop into females, into ZZ females. These ZZ females look like males and behave like males, but they produce eggs, in fact twice as many as their ZW co-sisters. Spotted hyenas Spotted hyenas have little left over for traditional gender roles, so little that the females have both penises and testicles. Of all mammals, spotted hyenas show the greatest deviation from stereotypical gender roles. Photo: CC0 Spotted hyena females have internal genitalia such as a uterus and ovaries, but the external genitalia are confusingly similar to those of males. The clitoris is so large that it looks like a long penis. And the labia are so swollen that they resemble testicles. And because the bitches produce a lot of testosterone when they are pregnant, they are bigger, stronger and more aggressive than the males. In spotted hyenas, it is therefore always the females who are the leaders of the herd. But if you want to see an animal with great gender diversity up close, you need go no further than a hermaphrodite in the freezer: Deep-water prawn Most deep-water prawns, i.e. the prawns you have on your plate, start life as males. The smallest prawns in the freezer are usually males. Photo: Vidar Ruud / NTB They look macho, which in shrimps means spikes on the back and feather-like growths on the flippers, and they make sperm. But then, as the shrimp grow larger, the spines and feathers disappear. And more importantly, they gradually begin to produce eggs. The male shrimp will slowly become female shrimp, and will be so for the rest of their lives. Would you like to see more about gender diversity in animals? Check out this BBC series on news TV: Meet a cockerel in hen feathers, the mother of half a billion termites and a young and inexperienced ostrich. Seeing and being seen is part of the game in open landscapes. Sex-changing clownfish, bisexual nudibranchs and warlike sea lions – the diversity is great in nature’s largest, oldest and wettest checkpoint.
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Animals that break all gender rules – news Documentary
