Bird With Poison Under Its Wings, Deadly Frog: What's Their Secret to Avoid Death By Own Toxins

Sometimes looks can be deceiving, especially in the animal kingdom. Those with the brightest colors and the smallest ones that look harmless may turn out to be the most poisonous animals on the planet.

For instance, a small, drab bird living in New Guinea called hooded pitohui holds a toxic secret beneath its wings. Despite its colorful appearance, hooded pitohui's orange and black feathers are laced with poison. Similarly, the small, bright-colored poison dart frogs have the ability to kill ten men despite their tiny appearance.

According to National Geography, these poisonous animals carry the toxin called batrachotoxin (BTX), which can stop sodium in a person's body, leading to paralysis or death. But poison dart frogs and hooded pitohui employ mechanisms that avoid getting poisoned from their own poison, which is a phenomenon called auto-intoxication.

So, how do poisonous animals protect themselves from getting poisoned by their own toxins?

Toxin Sponge Protects Poisonous Animals From Auto-Intoxication

For many years, scientists think that poisonous animals have evolved specially adapted sodium channels that are immune to BTX. Some animals, like Egyptian mongooses, shrug off toxins in this way to survive the venom of a cobra.

But the study, titled "Evidence that toxin resistance in poison birds and frogs is not rooted in sodium channel mutations and may rely on "toxin sponge" proteins" published in the Journal of General Physiology, disagrees with that concept. Researchers identified special proteins called toxin sponges that soak up and store the poison before they cause damage inside the bodies of poisonous animals.

They found that sodium channels of hooded pitohui and poison dart frogs are not immune to BTX, although only the poison dart frogs survived when the poison was injected into them. This led them to conclude that toxin sponge protein might be shielding the channels from getting poisoned.
Evolutionary biologist Rebecca Tarvin from the University of California, Berkeley, who had researched how poison frogs could tolerate the neurotoxin epibatidine, told National Geographic that seeing the sodium channels of poison frogs as not sensitive to BTX is something that she did not expect. However, she cautioned against overgeneralizing the results as BTX is only one of the many toxins that poison dart frogs.

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One Step Closer into Understanding How Poisonous Animals Survive A Harsh World

As Inverse reported, The findings of the study add to the information in cracking the puzzle of poisonous dart frogs and hooded pitohui birds and help scientists better understand evolutionary adaptations animals had to have to survive the harsh world.

They become poisonous animals as a defense mechanism to predators and turning their bodies to adapt to protect themselves. Most often, their bright colors are signals to predators that they should not be eaten.

Researchers propose further research on toxin sponges to confirm their full potential and determine their capability of binding BTX and other poisons. These additional studies will hopefully give more exciting insights that could be extended to humans by developing antidotes to protect them from harmful toxins.