It sounds crazy, but suicidal reproduction - also known as semelparity - is common in nature. There are a surprising number of animals that immediately die after having sex or not long after the mating season. The males in particular are forced to live fast and die young, often only surviving for about a year.
Scientists aren't 100% sure why semelparity exists, but it could have something to do with adaptation and survival. Males that die right after mating aren't sticking around to eat all the food and take up space. In some scenarios, the male's death even makes mating more successful for females. Another theory is that it's just a "quirk" of nature with no logical explanation. Regardless of the exact reason, there are some really fascinating facts about animals that die shortly after sex.
Furcifer Labordi Chameleons Die After Mating (If They Don't Kill Each Other First)
Furcifer labordi chameleons mate in January. It's "a nasty, often violent business of males fighting males, females fighting males, and all of them wishing they were somewhere else," according to Natalie Angier, writing for The New York Times. If they don't kill each other while trying to mate, hormone overdoses due to high levels of aggression might end them. Regardless, the males and females both die after successfully mating and laying eggs, and then just "drop from the trees with the papery grace of autumn leaves."
This particular species of chameleon spends two-thirds of its existence as an egg buried in the sand. These chameleons have the shortest lifespan of all tetrapods (four-limbed animals), often only lasting 4 to 5 months. They often spend more time developing as an embryo than they do after birth.
The males in all 12 species of the marsupial mammal antechinus die after their first time successfully breeding, typically from stressing themselves out. The stress of the breeding season destroys their immune system, leading to liver infections and parasites of the blood and intestines. While some females live to breed for another season, all the males perish.
That's not the only place males get the short end of the stick. As babies, the males are denied adequate milk by their mothers, who prefer to wean the females. Then, they end their year-long lives trying to mate with as many females as they can "in violent, frenetic encounters that can each last up to 14 hours," according to National Geographic.
Normal mating sessions for these mammals last at least a few hours at a time, and then the males immediately go on to find more females to mate with. By moving so quickly, these creatures give themselves no time to eat, drink, or sleep. With breeding seasons lasting around two weeks, the males are so exhausted from the repetitive intercourse that they perish, leaving the females to birth and care for the babies on their own.
Some female praying mantises bite their much smaller mate's head off after or even during fertilization. The male gets seduced by pheromones and a courtship dance beforehand, only to be killed after intercourse. Females usually don't take off the male's head in one quick chomp, but instead, they bite into it like an apple, prolonging the pain. Males appear to use their feelers to calm the female down beforehand, but it almost never works.
However, research shows that there's a benefit to this decapitation. Males have a "separate mini brain" in their tails, which activates once their heads are gone. It causes them to thrust more vigorously and speed up the process, making the mating more successful in the end.
Male Australian Redback Spiders Sacrifice Themselves After Sex
Unlike some animals that get sick or just die of natural causes after mating, male Australian redback spiders essentially sacrifice themselves after sex. Like their American cousin, the black widow spider, female redbacks devour males post-coitus if they make themselves available. During mating, males purposely put their abdomens near the female's mouth, even though she will likely squirt digestive juices on him and devour him from the back in the end.
Males who choose to sacrifice themselves "sire proportionately more offspring than do the partners that the female spiders choose not to chew." A male redback's lifespan is so short that he will likely die or get eaten by a predator before making it to another female's web anyway. So, most males don't survive their first time mating.