As predators go, snails may not seem particularly frightening. They do not possess great size, strength or speed, nor do they possess the teeth and claws that we as humans associate with dangerous animals.

Cone snails, however, do not rely on speed or strength to subdue their prey instead they release a cloud of toxins into the water and wait for the animals they hunt to stop moving. Different types of snails use different cocktails of poisons, which vary depending on their specific prey.

A new study, published in Proceedings of the National Academy of Sciences, finds that some cone snails use a weaponized form of insulin to disable fish.

“This is a unique type of insulin. It is shorter than any insulin that has been described in any animal. We found it in the venom in large amounts,” said senior author Baldomero M. Olivera, a distinguished professor of biology at the University of Utah in a statement.

A synthesized form of the insulin was tested on zebrafish. When the insulin was injected into the fish it caused blood glucose levels to crash. When dissolved into water it disrupted swimming behavior and the effect intensified as the animals were exposed for longer periods of time.

The researchers believe that the weaponized insulin allows cone snails to disable entire schools of fish at a time.

Cone snails primarily live in tropical marine waters and each species uses its own mix of venoms. The animal attacks by protruding its stretchy “mouth” to expel its toxins, The cocktails of poisons used by these snails are strong enough that they have killed people in accidental encounters. The snail then uses the same mouth-like appendage to engulf its stunned prey.

In order to better understand the snails and their fast acting venom, the researchers examined the gene sequences of the proteins in the venom. The team found two gene sequences that closely resembled insulin, specifically fish insulin, and further chemical analysis confirmed it. Specifically fish insulin was found in the species Conus geographus and Conus tulipa which both trap fish.

The fish insulin was not found in five species of cone snails that attack fish with a harpoon like organ. It was also not found in the venom of snails that prey on mollusks and worms, however mollusk and worm insulin was found in those species. This means that the snails have evolved to use the same, exact insulin which is produced naturally in their prey but the snails use it as a poison.

The snail insulin contains 43 amino acids which is less than any other known form of the hormone. The researchers are hopeful that the snail insulin could help scientists to better understand the systems that the human body uses to regulate blood sugar and metabolism.

Human insulin is known to be involved in type 1 and type 2 diabetes. According to the World Health Organization, 347 million people worldwide have diabetes and 1.5 million died of the disease in 2012. A better understanding of how insulin works in the human body could lead to better treatment for diabetes and possibly even a cure, someday.