You probably know by now—especially if you’ve been following Mother of Corals for a while—that coral polyps are animals, not plants or minerals. But did you know that they are carnivorous or that they hunt for their tiny little dinners?
As it turns out, corals share a hunting mechanism with jellyfish and other relatives in the phylum Cnidaria—specifically, a stinging cell called a nematocyst.
Most corals are colonial organisms, which means that the coral you see underwater is actually a large group formed from hundreds of individual coral polyps. These polyps each have a stomach with a single mouth that is encircled by tentacles.
Here’s where the connection to a jellyfish’s tentacles happens. Both animals have nematocysts on their tentacles. These tiny little cells contain a tightly wound thread attached to a stinging barb—like a whaling harpoon from the days of Moby Dick.
When a prey animal touches one of these cells, the covering on the nematocysts flies open and the barb flies out at the end of its tether, embedding itself into the prey and injecting a poisonous liquid that stuns or paralyzes the unfortunate animal.
The hunter’s tentacles then haul the prey toward its mouth where it is consumed. Pretty intense, right? Fortunately for humans, these cells are incredibly tiny, so we’re not at risk of becoming a coral colony’s dinner.
Like most jellyfish, a coral’s sting is not lethal for humans, causing a slight irritation or rash at most. Sometimes little pieces of the tentacles may break off, which is what most folks who get zinged during an ocean excursion are experiencing.
A thin wetsuit, or simply avoiding contact with the coral reef is enough to protect human skin. This also protects the fragile corals from being damaged by an unintentional arm swing or leg kick.
Want to learn more? The National Oceanic and Atmospheric Administration has a great tutorial on corals at:
https://oceanservice.noaa.gov/
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by Guest Blogger, Chad Koll
Chad Koll has a masters degree from Scripps Institution of Oceanography and works for Scuba Schools International as their International Product Manager. He also serves on the Board of Directors for Mother of Corals.
