In nature, there are many animals that suck blood - mosquitoes and butterflies stick to mammals, some species of fish and birds prefer their own kind. Among warm-blooded animals, vampirism is seen only in bats. RIA Novosti talks about real bloodsuckers and finds out if there are such among people.
All for the sake of posterity
For female mosquitoes (Culicidae), human blood is a favorite treat and a source of protein necessary for the maturation of eggs. The more blood a female drinks, the more numerous and healthier her offspring.
The female lays three hundred eggs every two to three days. A lot of "building material" is needed, so the mosquito is constantly looking for prey. She can smell it for several kilometers - by the smell of lactic acid contained in sweat, by exhaled carbon dioxide and heat radiation from the body.
Before sucking, the female moistens the bite with saliva, which relieves it and prevents blood from clotting. It is saliva that subsequently causes irritation and itching, with it, serious infectious diseases are transmitted to a person - malaria, yellow fever, Zika virus.
Only female mosquitoes drink blood; males feed on plant nectar / C BY 2.0 / John Tann.
Male mosquitoes do not drink blood, they feed only on plant nectar.
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Reluctant bloodsuckers
The Siberian night moths (Calyptra thalictri), which live in Siberia and the Far East, are also predominantly vegetarians. Their diet is dominated by juices of berries and fruits: raspberries, peaches, grapes. But some individuals can suddenly change their diet and switch to the blood of mammals, including humans.
Scientists hypothesize that the reason is the underdevelopment of sensilla - small sensitive processes on the antennae of insects responsible for smell. Moths hardly distinguish the smells of animals, so they "taste" a motionless human finger. And once having drunk blood, he is no longer able to refuse, because it is much more nutritious than fruit juice.
Siberian night moths feed mainly on juices of berries and fruits, but sometimes human blood is included in their diet / CC BY-SA 2.0 / Ilia Ustyantsev.
Vampire fish
A small transparent catfish kandiru (Vandellia cirrhosa) lives in the rivers of the Amazon and feeds only on the blood of larger fish, swimming in their gills and biting through the blood vessels. In a minute, he satisfies his hunger and swims away in search of a new victim, which he calculates by the smell of ammonia released from the gills when breathing.
It was this circumstance that turned the ectoparasite, harmless for humans, into a “Brazilian vampire”, which the locals are very afraid of. Among the Indians, there is a tenacious myth that kandiru, sensitive to the content of ammonia in the water, is able to penetrate the vagina, anus, urethra, from where it can be obtained only by surgery. However, there is no reliable evidence of this.
Looking for water
The sharp-billed ground finch (Geospiza difficilis septentrionalis), which lives in the Galapagos Islands, is a small songbird weighing about twenty grams. She drinks the blood of large birds - blue-footed (Sula nebouxii) and Nazcan (Sula granti) boobies.
The finch descends on the victim's back, pierces the skin in the area of the tail feathers with a sharp beak, and swallows the blood oozing from the wound. It is believed that this is how the birds solve the problem of the shortage of fresh water on the islands.
Sharp-billed ground finch drinks the blood of large seabirds / CC BY-NC 2.0 / Charles Davies.
Interestingly, the gannets almost do not resist the bloodsucker, because the finch benefits them - it pecks out parasites from bird feathers.
Altruistic vampires
Bird's blood is also an important item on the menu of Upland Vampires (Diphylla ecaudata), bats native to Central and South America. However, their close relatives - the common vampire (Desmodus rotundus) and the white-winged vampire (Diaemus youngi) - prefer the blood of vertebrates, including humans.
Due to the low carbohydrate content in the body, vampire mice are forced to eat abundantly and often. An individual that has starved for three days will lose a quarter of its weight and will most likely die of starvation. Therefore, the bats of the same nest share with each other - they vomit blood clots into the mouths of fellows who are not able to hunt.
Vampire bats feeding on the blood of vertebrates share surplus food with each other / CC BY-SA / Uwe Schmidt.
Vampires among humans
Real hematophages, that is, those who feed on the blood of vertebrates, are found among people. But this condition is always associated with mental disorders. The most famous is Renfield's syndrome, the so-called clinical vampirism. Most often men suffer from it. They have an uncontrollable urge to drink the blood of mammals, including humans.
The medieval legends of Central Europe often feature vampire people. It is believed that all these legends are associated with the fear of patients suffering from a rare genetic disease - porphyria. Problems with the synthesis of hemoglobin (red blood cells) in such people disrupt pigment metabolism in the blood and tissues.
Their skin is thin and pale, their teeth are reddish or reddish-brown. They avoid sunlight, which can severely burn them, and do not eat garlic, as the organic sulfides in it can trigger an attack of illness.
Alfiya Enikeeva