A 40 minute time lapse of a medicinal leech feeding. When this medicinal leech (Hirudo verbana) bites into its host it releases a protein called hirudin which will prevent blood from clotting and keep blood flowing from the wound for hours. This is an important property in medicine which is why surgeons and doctors use it in
surgery and medical treatments.
Leeches can go for over a year without feeding, and when they feed they can grow several times their original size as they swell with blood from their meal. They will slowly digest their blood meal until they have another opportunity to feed again.