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Naja

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The genus *Naja* consists of venomous snakes commonly called "true cobras."

Indiancobra
Indiancobra

These snakes are found across Africa, Southwest Asia, South Asia, and Southeast Asia. While other animals like the king cobra are often called cobras, they do not belong to this specific genus.

Naja haje (1)
Naja haje (1)

Understanding *Naja* is vital because these snakes are medically important due to the many bites they cause. They are a diverse group with complex biological traits and varying levels of toxicity.

Most *Naja* species have slender bodies and vary in length. The forest cobra, or *Naja melanoleuca*, is considered the longest species in the genus.

Cobra des forêts
Cobra des forêts

These snakes possess a unique defensive behavior. When threatened, they raise the front part of their body off the ground. They also flatten their necks to look larger to potential predators. This display is a primary way they signal danger to anything approaching them.

Venom delivery in cobras can happen in several ways. Most species use fangs to inject venom downward, much like a hypodermic needle. However, certain species are known as "spitting cobras."

Red Spitting Cobra
Red Spitting Cobra

These snakes have specialized fangs with a short, rounded opening on the front surface. Instead of biting, they squirt venom forward out of their mouths as a defense. This venom can cause severe burning in the eyes and even permanent blindness if not washed out immediately.

Naja melanoleuca head dissection A- fang B - venom gland
Naja melanoleuca head dissection A- fang B - venom gland

The chemical makeup of cobra venom is highly complex. Many species possess neurotoxic venom, which attacks the nervous system and causes paralysis. Other species have cytotoxic properties, which cause tissue death known as necrosis and significant swelling. Some venom also contains cardiotoxins that affect the heart or anticoagulants that interfere with blood clotting.

Naja philippinensis
Naja philippinensis

Recent studies suggest that spitting lineages evolved higher levels of phospholipase A2. This enzyme increases the pain caused by the cytotoxins already present in the venom.

Taxonomic history shows that the number of recognized species in *Naja* has changed significantly. For a long time, scientists identified only 20 to 22 species. However, a major revision in 2009 merged the genera *Boulengerina* and *Paranaja* into *Naja*.

Boulengerina annulata 2
Boulengerina annulata 2

This revision expanded the genus to include 38 species. The name *Naja* itself comes from the Sanskrit word *naga*, meaning snake. Some researchers suggest the name may also be related to the Sanskrit word *nagna*, meaning hairless or naked.

Potency varies greatly between different species. The Caspian cobra, *Naja oxiana*, is the most venomous species in the genus.

Naja oxiana (6)
Naja oxiana (6)

It has a recorded lethal dose (LCLo) of only 0.005 mg/kg. This is the lowest lethal dose ever recorded among all cobra species. Other highly toxic species include the Philippine cobra and the Chinese cobra.

The mortality rate for untreated bites can be extremely high. For example, untreated bites from *Naja oxiana* have an mortality rate approaching 80%.

Medical treatment for cobra bites depends heavily on the species involved. For many species, such as the Philippine cobra, patients respond very well to antivenom if they receive it quickly.

However, *Naja oxiana* is much more difficult to treat. Its venom causes intense local damage like blistering and bruising, along with kidney and heart issues. Even with medical care, the mortality rate for *Naja oxiana* remains high at about 30%. This is because antivenom is often less effective for this specific snake, frequently requiring massive amounts of the serum to work.

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🖼️ Images & Media (26)
File:Indiancobra.jpg
Indiancobra.jpg
File:Naja melanoleuca head dissection A- fang B - venom gland.jpg
Naja melanoleuca head dissection A- fang...
File:Boulengerina annulata 2.jpg
Boulengerina annulata 2.jpg
File:Snouted Cobra, Naja annulifera, Waterberg, South Africa.jpg
Snouted Cobra, Naja annulifera,...
File:Naja atra (03).jpg
Naja atra (03).jpg
File:Naja haje (1).jpg
Naja haje (1).jpg
File:NajaKaouthia.jpg
NajaKaouthia.jpg
File:Naja Katiensis.jpg
Naja Katiensis.jpg
File:Naja mandalayensis (Chao Li).jpg
Naja mandalayensis (Chao Li).jpg
File:Cobra des forêts.jpg
Cobra des forêts.jpg
File:Mozambique spitting cobra (Naja mossambica).jpg
Mozambique spitting cobra (Naja mossambica).jpg
File:Congo dwarf water cobra, Naja nana.jpg
Congo dwarf water cobra, Naja nana.jpg

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