Last week, a client sent me a photo of a hammerhead worm. To be honest, I had never seen one or even heard of it before. I thought this article would shed more light on this unique creature. Read here to find out more information about hammerhead worms.

Hammerhead worms are flattened, very long earthworms, and have a broad shovel-like head. They can be 10 or more inches in length. Please see the picture below received from a Warren County resident.

Hammerhead worms are earthworm and mollusk predators and have been a problem in earthworm farms. These are terrestrial planarians. They are able to detect secretions left by earthworms in the soil, and then track, kill, and consume those earthworms. They are able to kill earthworms many times their size as hammerhead worms can use a neurotoxin (tetrodotoxin) to paralyze the worm. Hammerhead worms have the potential to greatly impact local earthworm populations. These hammerhead worms have few predators.

Reproduction can be sexual, or asexual as all the species are hermaphroditic.  Some species can use fragmentation, fission of posterior body fragments. These diverse reproductive strategies enable hammerhead worms to spread rapidly.

While there are native hammerhead worm species, this species appears to be invasive from southeastern Asia; however, I am not able to confirm this. This species is widely distributed and has been in the United States for over a century.

Information for this article was taken from Ric Bessin, Entomology Extension Specialist Kentucky Pest News article published on September 8, 2020 found at https://kentuckypestnews.wordpress.com/2020/09/08/hammerhead-worms/.