Before we explore venomous invertebrates, we have to explore the concept of venom and how venom differs from a poison.
What is the meaning of venom?
A venom is a chemical that is secreted by an animal that is specifically evolved to either paralyze or stun potential prey or predators. Moreover, people often tend to get confused between venom and poison, however, both are distinct from each other. Their primary distinguishing factor is the mode of administering the chemical cocktail to prey or predators. For instance, venomous animals always inject venom through stingers, hypodermic fangs or spines. Moreover, these animals usually have a venom sac where venom is produced and stored. On the other hand, a poison is a chemical where its ill effects occur if the chemical is absorbed, inhaled or swallowed.
Moreover, venom has evolved for a specific purpose while poison serves a generalistic function. Many invertebrates animals are venomous while most vertebrate animals are poisonous. For instance, the venom of the Conus geographus, a sea snail, is potent enough to hunt fish. However, the venom is so potent that it also kills humans. In fact, the venom is so dangerous that there is no anti-venom if you are unlucky enough to get stung. On the other hand, the Poison dart frog is an example of a poisonous animal. This is because you become poisoned if you touch the frog – where the chemicals on its skin are absorbed through your skin.
What are the Types of Venom?
Based on the biological effects of the toxins in venom, it can be classified as follows:
Necrotoxins are named so because they cause necrosis when they come in contact with cells. This means the cells start dying prematurely, which can become fatal for the organism. Necrotoxic venom is commonly seen in many species of vipers.
Neurotoxins primarily affect the nervous system, by causing destruction to nervous tissue. Such type of venom is possessed by the Black widow spider, box jellyfish, cone snail and many other invertebrates.
Myotoxins are destructive to the muscle cells. This class of venom is commonly found in rattlesnakes and lizard venoms.
Cytotoxins are destructive to individual cells. Black widow spiders and honey bees are known to carry this class of venom.
Examples of Venomous Animals
Following is a list of animals that are known to be extremely venomous.
1. Box Jellyfish
Box jellyfish are marine invertebrates that produce an extremely potent venom. If stung, the pain is extreme and can often result in fatalities. It delivers its venom through microscopic needle-like cells called nematocysts which are present in its tentacles. When the tentacles brush against another organism, the nematocysts fire into the skin, causing envenomation.
2. Black Widow Spider
Black widow spiders are arachnids with potent venom. It is excruciatingly painful and can lead to death if left untreated. This spider delivers its venom through hypodermic fangs which are large enough to pierce human skin.
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