To the disgust of many of our readers, we recently discovered that keeping leeches as pets is actually a thing.
And yeah, it’s certainly… a bit different. But in light of humanity’s disconnect with nature, and our concerning lack of knowledge about parasitic creatures, the idea that some of us are nurturing these parasites is also, uh, fascinating.
“They’re amazing, curious creatures that grow like crazy and make wonderful pets,” leech keeper Ariane Khomjani told ScienceAlert.
He explained how individual leeches have their own unique personalities, with some being more adventurous and others more shy.
“Some like to try and sneak a feed more often than others, haha! But once they’re full, they’re content to sit and rest for a bit out of water if handled gently,” he said.
Khomjani has four of these squishy vampires, including Leara who is pictured below. The species he keeps is one of the larger types: buffalo leeches (Hirudinaria manillensis) from Asia.
There are over 600 leech species worldwide and most, but not all of them, are blood suckers. Others, like worm leeches (Pharyngobdellida), are predatorsthat swallow their invertebrate prey whole, while some species are detritivores that eat organic debris.
These wriggly sausages can have up to eight pairs of ocelli (eye spots), which they use to detect the shadows of potential prey. Their brain bits are spread across 32 body segments, and they are hermaphrodites, so each individual leech has both male and female organs, although they still require a mate to breed.
If a hungry parasitic leech senses your body heat or the CO2 in your breath, it can loop its way towards you by using its mouth and butt suckers. Yes, you read that right, their butts suck, too.
If it finds a suitable bit of host, the leech will inject its saliva – which contains anaesthetic and anti-blood clotting compounds – before biting down with two- or three-pronged serrated jaws.
“Once they get feeding you don’t even feel it, even with the large buffalo leeches,” explained Khomjani, although the initial bite can hurt a bit. They can go up to a year between feeds, but leech sellers recommend feeding the larger species every 3-6 months.
Of course, as with anything involving direct contact with your bloodstream, feeding a leech your own blood should not be attempted without first seeking advice from a doctor. Some people are allergic to leech saliva and there’s always a risk of catching an infection from them.