Grey Heron wading in shallow wetland water, patiently waiting for something to swim within striking distance. Ngorongoro Crater, Tanzania.
Warning: do not read this post at the dinner table.
defensive vomiting
Some species use a survival tactic that’s as effective as it is disgusting: defensive vomiting. Academics chew it in the literature as emesis or defensive regurgitation. The gist is simple: when surprised or threatened, some animals puke up the half-digested contents of their stomach to get out of a jam.
The blast of the grey heron
This rancid blast is a key part of the defensive arsenal of the Grey Heron (Ardea cinerea). Here is why their high-velocity vomit is so effective:
It can blind or burn an attacker. The gastric soup of a Grey Heron (pH 1.0 to 2.0) is significantly more acidic than vinegar or lemon juice. In fact, it is nearly 100 times more acidic than human vomit—and we all know how pungent that can be! This potent acid allows herons to rapidly dissolve fish bones, cartilage, eels, small mammals, etc, but when weaponized, it’s a caustic deterrent.
It provides a distraction. Even if the heron doesn’t score a direct hit, a well-timed “gift” can be a lifesaver. It presents an interesting and soggy morsel that acts as a bribe, distracting a predator long enough for the heron to make a clean getaway.
It lightens the load. Taking off from a standstill is hard work. Dumping a heavy, half-digested meal makes the heron lighter and more agile for an emergency liftoff. And hey, who doesn’t need that?
The Acid rain Bird
These birds often nest in colonies, called heronries, consisting of dozens or even hundreds of pairs. Because they return to the same tall treetops year after year, the ground beneath them often becomes a wasteland. The “acid rain” of guano and regurgitated remains is so toxic that it frequently kills off the vegetation below.
So, when you’re trekking through the wetlands of Africa, remember the rules: watch your step, don’t look up with your mouth open, and try not to startle the locals.
Check out another member of the Ardea family, the Black-headed heron. See the post, “The Serengeti’s Stealth Artist: Meet the Black-headed Heron.”
Bible Land Explorers are headed back to Tanzania June 3-13, 2027. Lake Victoria, the Serengeti, and Ngorongoro Crater, are on our agenda as we photo-hunt big cats, small birds, and everything in-between. We are now receiving early registrations for this exclusive small-group adventure. See the link here for brochure and more information or email us at BibleLandExplorer@gmail.com.