Black widow spiders, cobras and mantises. We are talking about species belonging to the group “sexual cannibalism”“, or mate predator. To obtain nutrients during pregnancy, the females of these species, after mating with males, often kill and eat them. The most famous of these is perhaps the most famous of these. is a mantis with the image of male beheaded.
But in a new study in the journal Ethology, scientists report for the first time a species of snake called Montpellier (Malpolon Monspessulanus) that lives in the south of France. There, the males of this snake eat the female.
They were greatly puzzled when they discovered the paradoxical cannibalism in this snake. It is extremely counter-intuitive and creates a contradiction in the theory of evolution. Logically, if all male Montpellier snakes mate with females and then eat them, the young would never be born and the snakes would go extinct.
The Scientist magazine interviewed one of the paper’s authors, biologist Xavier Glaudas from the University of the Witwatersrand to shed light on what’s going on with this Montpellier snake.
While mantises, black widow spiders, and most cannibals eat only males, these male Montpellier snakes eat females.
“I was surprised and wanted to say, ‘Are you serious? Is this true?“, said Glaudas. That’s when he noticed that not one but three male Montpellier snakes had been discovered as they ate the female during the mating season.
Glaudas’ colleagues photographed these events, and several Montpellier snake experts confirm it. “They recognized this as a case of 3 male Montpellier snakes eating adult females“, he said.
“Then I thought, “Okay, okay, we need to put all this evidence together. We’re going to write a report on this. It’s pretty counter-intuitive and we need to make it public.” .
In a study published in the journal Ethology, Glaudas reiterates the fact that cannibalism is not a new phenomenon in the animal kingdom. However, it’s usually only one-way, with larger-bodied females eating smaller males after mating with them.
It is particularly rare for males to kill and eat adult females, and there is hardly any theory to explain it. Because killing females often causes males to lose potential mates or their offspring cannot be born.
“Nearly every biologist like us thinks it’s counter-intuitive to have a species where adult males cannibalize adult females.” said Glaudas.It wasn’t until we compiled all the facts and wrote this article that we realized, in fact, there are still many reasons to explain such behavior.”
The first reason, according to Glaudas, these male Montpellier snakes may have misidentified prey. Montpellier snakes are opportunistic predators and they are very aggressive. “Maybe these male snakes saw something move and immediately went into hunting mode“, he said.
After rushing to attack the female, the male discovered that the prey was a fellow. But once the struggle had begun, they could no longer make peace and stop. The male snake must kill the female or vice versa. But in this snake, the male body often seems to outperform the female, so they won.
Two Montpellier snakes are fighting for survival. Then the male won.
Even so, the first hypothesis does not explain why the male Montpellier snake then ate the female. This leads Glaudas to the second hypothesis, that these snakes are very hungry. “It is likely that typical Montpellier snake prey this season is scarce, and the snakes have turned to hunting unusual prey.“, he said.
“Although not very often, Montpellier snakes sometimes eat other snakes.” And when they spot a female Montpellier, they take their chance. Initially, the snake may pretend to come to mate, or it may be that when the mating is complete, they will kill their mate and eat the flesh.
Is this counter-intuitive and against the theory of evolution? In the event that only a few very hungry male snakes do it, there should be no problem for the Montpellier species as a whole. Because males in the animal kingdom tend to mate with multiple mates, a behavior that maximizes their reproduction.
Montpellier male snakes also need energy and they can eat a single female to survive and mate with other females.
The third theory Glaudas put forward is that Montpellier snakes are killing and eating adult females as a way of eliminating competition. “Members of the same species are your worst competitors because they live in the same niche with you.”, he said.
“They use the same resources, they often eat the same items or prey. So by killing and eating one of your kind, you’re eliminating the strongest competitor you face.”
When asked which of the three theories he leans the most, Glaudas said he doesn’t know either. Even those may not be the best theories. “We can only speculate in this case“, Glaudas admitted.There may still be other possibilities.”
Scientists have recorded at least three cases of male Montpellier snakes eating females in just one of their mating areas in the south of France.
However, this is still a very special finding, because female snakes eating male snakes have been reported before. But there is a species of snake in which the male eats the female, and this is the first discovery.
“There is a recently published article on the African cobra. In it, scientists show that in the world of cobras, they can eat each other. But those who are eaten are always males. They did not report a single case of a male eating a female“, said Glaudes.
“Although we have only observed three cases, we believe that male cannibalism may be more frequent with this Montpellier snake.”
The study was published in the journal Ethology.
Refer to Thescientist