• Slow lorises are the only known primates with venom
  • Researchers found that their venom is strikingly similar to cats' allergenic proteins
  • It is possible that cats evolved the allergenic proteins as a means to avoid predators

An international team of researchers shed light on why so many people are allergic to cats and they found the possible answer in an unlikely source: the only known venomous primate in the world.

Defensive Venom

When slow lorises fight with other slow lorises, it causes slow healing wounds in their opponent. When humans get bitten by slow lorises, however, it results in symptoms that resemble allergic shock.

For a new study published in the journal Toxins, researchers analyzed the DNA sequence of the protein in slow loris venom and found it to be “virtually identical” to cats’ allergenic proteins. As it happens, cats do secrete this protein and coat themselves in it, causing a reaction in people who are allergic to them.

According to the researchers, it is possible that just like slow lorises, cats may also be using this protein as a defensive weapon by coating their fur with it. This could mean lorises and cats evolved similar allergic triggers separately.

Allergic Reaction

“The fact that so many people are allergic to cats mightn't be a coincidence,” team lead Dr. Brian Fry of the University of Queensland said. “This may have been evolutionarily selected for in the wild as a defense against predators. The human allergy to cats is so prevalent that it would be a remarkable coincidence if this wasn't an evolved defensive weapon, like the same protein used by slow lorises.”

In other words, although modern-day cats may not be aware that they are causing the reaction in people, it is possible that they have evolved and still have the defense that could keep potential predators away. In allergic people, the reaction can range from itchiness to welts and sneezing fits.

According to Dr. Fry, the results of their study have opened up new areas of allergy research and, future studies could look into the possibility that ant and bee allergies might have also arisen from the same mechanisms.

Further, there is also the question of why bigger cats have less effective versions of the allergen. In this case, it might be possible that because they are already apex predators, they no longer need the defense as much as the smaller cats.

Slow Loris
The slow loris is the only venomous primate in the world. Wikimedia Commons