How many times have I heard someone say, “Look, it’s a poisonous snake!”? Too many to count! Most people do not know the difference between poisonous and venomous, but there are some fundamental things you should know about these toxic terms.
Poison is defined as any toxic substance harmful to a living organism. For our purposes, we are focusing on the poison produced by plants and animals.
In the animal and plant world, poison is a toxin that must be ingested (such as eating something) or absorbed (such as through the skin). Poisons can have many potential effects, from simple skin irritation and burning, to stopping specific processes within the body.
There are many examples of poisonous organisms. Numerous plant species use poison as a way to protect themselves from animals that may want to eat them. There are plants all around us that are poisonous. The most obvious, locally, being poison oak, which can cause blisters and skin irritation upon contact. There are many ornamental plants that we may not even realize are toxic, including the oleander plant we see all up and down I-5, which possesses poison in every part of the plant including the flowers and the stalks. There are even poisons in many of the plants that you eat, just in small enough amounts that it will not cause harm to humans.
Poison in animals is generally used for the same thing, to protect the animal from predators or pests. Many insects are poisonous, such as beetles, caterpillars, and millipedes. The Monarch butterfly and Pipevine Swallowtail butterfly are poisonous if ingested. Amphibians, including frogs, toads, salamanders and newts, sometimes secrete poison from their permeable skin, some only mildly toxic, others incredibly deadly such as the poison dart frogs. There are some birds that are poisonous to the touch, such as the pitohuis – a bird native to New Guinea that secretes poison through its skin and feathers. Some of these poisonous animals do not actually make the poison themselves, instead getting it from the insects or plants that they eat.
Venom is a toxin that is delivered via a sting or bite. Venom must be introduced into the blood stream and carried through the vascular system to be effective. Venom can safely be swallowed without having any effect, as long as there is no cut in the mouth or ulcer in the stomach that the venom can go through, and the stomach acids will break down the proteins same as they do any other food.
Venom is a mixture of enzymes and proteins, chains of small molecules called amino acids found in living organisms. These chains are diverse in the pattern of the amino acids, causing the strands to be different and therefore causing a variety of effects to happen in the body. There are two types of venom. Neurotoxic venom affects the nervous system, cutting off the transmitters that send messages between the nerves and causing paralysis. Hemotoxic venom affects the vascular system, breaking down the tissue and causing hemorrhaging throughout the body. Many types of venom are a mixture of neurotoxins and hemotoxins.
In the animal world venom is quite common. Insects, such as ant, bees, and wasps, have a venomous sting that is mostly used for defense in these small animals. Arachnids (spiders and scorpions) are notorious for their venom that they use to subdue their prey – spiders via fangs and scorpions via stingers. Fish can be venomous. The beautiful lionfish is covered in spines with venom-tipped ends, while stingrays deliver their venom through a barbed tail tip. Many aquatic Mollusks (octopi, squid, and snails) and Cnidarians (jellyfish) use venom to incapacitate quick moving underwater prey.
Reptiles may be the animals that come to mind most often when we think of venomous creatures. Many snakes use venom to kill prey, and even begin digestion before the snake ingests the prey item. Some snakes have such mild venom you wouldn’t know it if you were bit, such as the garter snake. Other snakes have highly adapted venom delivery systems that use movable, hypodermic-like fangs to inject potent, fast-acting venom, such as rattlesnakes. Lizards can be venomous too; the Beaded lizard and Gila monster of the southwest United States and Mexican deserts have strong jaws with serrated teeth that they use to chew the venom into the prey, and may help in defense against predators in these slow moving lizards. Recent studies show that monitor lizards, such as the Komodo Dragon, also have venomous saliva.
The most surprising venomous animal is the Playtpus, a marsupial mammal native to Australia that looks like a cross between a duck and a beaver. The males in this unique species have spurs on their back feet that are used to deliver painful venom. It is thought that the venom is used during breeding season in an offensive manner to assert dominance over other male platypi.
Toxic substances are found throughout nature. It can be an effective way to protect both plants and animals, and are used by animals to subdue and even begin digestion of prey. Educate yourself about the species around you to keep yourself safe and avoid any dangerous plants and animals in your area. If an encounter occurs with any toxic organism, seek medical assistance. None of these plants or animals are out to get humans; we must learn to coexist with all parts of the natural world.
Adrienne John, Head Animal Trainer