Another tale from the weird and wild world of animals! Cone snails are a large group of deadly snails. You probably don't usually think of snails as being deadly, but once you see these critters in action you'll understand why. Cone snails are predacious, and the variety we are focusing on here, Conus geographus and Conus tulipa are aquatic, fish-eating snails. These 4-6 inch long snails harpoon their prey and inject them with venom, a cocktail of toxins that cause paralysis in their fish meal. The snail then proceeds to engulf the slowed fish with its expandable mouth.
|"Conus-geographicus" Credits : Kerry Matz National Institute of General Medical Services, Wikimedia Commons|
|"Conus tulipa 1" Credit: Almed2, Wikimedia Commons|
As most of us know, insulin is a hormone that regulates metabolism. Insulin is produced in humans naturally, and in cases where the body does not produce the necessary insulin, such as diabetes, it is given to help regulate metabolism and balance out the production of glucose in the blood. The insulin found in the snail venom is specific to fish, rather than molluscs. The snail is making very specific insulin which makes the blood sugar of the fish drop and quickly makes them groggy. In concert with the neurotoxins in the venom, the snail very easily immobilizes its meal. Researchers believe that the insulin slows the fish down long enough for the snail to inject more of the venom into it, assuring its prey is able to captured.
This is a great example of the diversity of hormones and how important body chemistry is. In some cases, insulin is used to restore regular metabolic function, in other ways it can be part of a deadly hunting strategy. Studies like these are a great way to integrate, biology, chemistry, health, endocrinology, animal adaptations into a science lesson! For further reading on the predatory adaptations of sea life, check out my post on electric eels.
- Science News: "Cone snail deploys insulin to slow speedy prey"
- Proceedings of the National Academy of Sciences: "Specialized insulin is used for chemical warfare by fish-hunting cone snails" (Abstract)
- Live Science: "Venomous Cone Snails Weaponize Insulin to Stun Prey"
Ocean Adaptation and Insulin Information, Activities and Resources:
- All About Cone Snails
- Jean-Michel Cousteau Ocean Adventures: Adaptation Activities
- Kids Health Dictionary: Insulin
- Kids Health: Diabetes Center