Animal Survival Skills: Poison Edition
To get the irritating or bad things out of your system humans use gagging or vomiting but not all animals use these techniques when they need, instead they use several other tactics.
For example because of the arrangement of their digestive system horses can’t vomit. Well we know how our inner discomfort leads to vomit. It normally starts with a gag reflex, which constricts the back of our throat. Our abdomen’s repeated constrictions then trigger contractions that force stomach contents back into your esophagus. This eventually propels your lunch out of your mouth.
Horses can’t do this because of their esophageal sphincter. That’s the valve that makes sure food system stays in our stomach once we swallow it and this part is much stronger in horses. Moreover, the angle between a horse’s esophagus and its stomach is a lot like a bend in hose. Vomiting creates pressure on the stomach and so to alleviate it we have to unbend the hose by re-arranging the horse’s insides, or try to add enough pressure to force vomit through the bend. But the problem here is that animal stomachs would burst before anything got into its esophagus. So ejecting toxins via mouth is very rare for horses. The vast majority of nutrient absorption happens in the horse’s intestines and colon, and diarrhea is a quick way to clear these organs before they can absorb something that seems dangerous.
What Rats Do
Rats also can’t vomit partly because of a similar valve problem to horses, and partly because their muscles can’t physically make the movement that would get food up their esophagus. Instead a rat that thinks it’s been poisoned will try to cure itself by eating other things, a behavior known as pica. Rats are picky eaters when they are nauseous. They will ignore soils and pebbles in favor of kaolin, a kind of clay. The more nauseous researchers make the rats, the more clay they’ll eat and rats given medications that reduce nausea will go right back to eating rat food. Clay-eating seems to be a rat’s way to self-medicate. Biologists still don’t why they do that but the metal ions in kaolin bond well with some toxins meaning that the rat doesn’t absorb them.
There are also the animals who don’t need to vomit but they can. They use it as a defense mechanism. Turkey vulture eats rotten meat, which can contain very harmful bacteria. So if they had to hurl and go through the struggle, they would hardly be able to keep a meal down. Instead turkey vultures guts are extra acidic which kills off most of the bad bacteria before it has a chance to hurt them. They have also evolved tolerance for certain species of bacteria that can cause massive die-offs in other birds. Those bacteria help them with digestion. But turkey vultures can vomit. They just do it on purpose, up to 3 meters. It’s a super effective strategy. Most people and animals hate being vomited on. Plus turkey vulture vomit can be especially acrid and corrosive. So if you ever encounter an angry vulture, you might want to back away.
Transcripted by Benazir Elahee Munni