There was a time when, in the American West at least, thatbars and saloons had what were called spittoons, containers on the floor for patrons to spit into. Chewing tobacco was widespread then, a century and more ago. People who chewed tobacco, mostly men, chewed and spit. The spittoons were preferable to a slimy brown floor. That has long gone, and all tobacco use in the U.S. is down sharply. Spitting in the U.S. is frowned on, considered gross and may get you arrested.
So spitting has become mostly extinct. Among humans, that is. Among animals, it’s evolved in some interesting ways and is more common that most people know.
Perhaps the most interesting and weird example is the Bombardier Beetle, Brachinus alternans being one species. There are about 500 species of these fellows. They have two glands near the tip of their abdomen. One contains hydrogen peroxide and acid in a sort of reservoir and the other is filled with water and chemicals.
When the beetle feels threatened, it squeezes contents together and a remarkable chemical reaction occurs—the temperature gets to the point of boiling water, 212 F (or 100 degrees C), and the pressure instantly builds, and the beetle shoots out a mix of boiling water, steam and some noxious chemicals. The beetles can shoot for 20 cm, about 8 inches, with good accuracy, and can repeat the process several times. They are found on every continent, with about 40 kinds in the U.S.
It’s not exactly spit, being closer to the way a skunk sprays. The beetles actually shoot a series of pulses or their corrosivemix. It is powerful enough to burn human skin and could affect a human eye. It must be a nasty surprise to a bird or lizard or toad that sees lunch until lunch starts shooting at them.
Another spitter is fairly well known, the spitting cobra. There are about 20 species of spitting cobras, found in Africa and Asia. The snakes are all in the Naja cobra family and can inject venom through their fangs. That’s also how they spit, and their fangs differ somewhat from the many species of cobra that don’t spit. It’s defensive, unlike venom, which is used to subdue prey. The spray is harmless if it hits skin or other body surface, but if it hits eyes, it can cause blindness.
It’s actually an elegant defense. The snakes spit at the eyes of predators and while the predator is temporarily disabled, the snake escapes. It must work well because it has independently evolved at least three times. The snakes are rather accurate, and some can hit targets as far as ten feet away. That’s far enough to hit the eyes of most of their predators. The snakes are typically 2 to 8 feet long, and can live up to 20 years
A third spitting creature spits for food, not for defense. These are the Archerfish, native to Southeast Asia. They prefer brackish water in mangrove forests but are adaptable One species is Toxotes jaculatrix. There are five known species.
The archerfish spits a stream of water at insects above the water surface. This is harder than it might seem, because the fishes’ eyes are underwater, and there is some refraction of light at the water surface. Archerfish can hit insects as far as 5 or 6 feet above the water, and they can hit a flying insect. The hit knocks the insect to the water, where the fish can gobble it down. They are quite accurate. Their eyesight is better than most fish, and it’s binocular. That means they can aim with precision. They can live up to 10 years in an aquarium, although they are difficult to keep. The fish get up to about 12 inches long.
Deep knowledge, every day.
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