Fact of the Day .CA

Spanish ribbed newts (Pleurodeles waltl) have been known since 1879 to protrude sharp spines from its sides as a defensive behaviour against predators.  National Geographic compared this behaviour to the X-Men Wolverine extending his metal-infused bone claws through the skin of his hands.  Only this year (see study here) has it been discovered that these spines are actually the tips of the animal’s ribs.  Other newts are known to excrete toxic compounds as well as move their ribs using special joints to make their bodies appear larger by stretching the skin.  The Spanish ribbed newt also does these two defensive behaviours, except that their ribs are longer in proportion to their bodies and protrude through the skin of their sides.  The ribs are rotated forward and are seen underneath orange warts on the newt’s side.  These orange warts are proposed to enhance the visibility of the rib tips.  These rib tips appear to be thicker for durability and coated with a thick membrane thought to protect against pathogens.  Like most amphibians, the Spanish ribbed newt has evolved the ability to quickly heal its skin; this is especially important for them because their ribs cut through their skin every time they perform this defensive behaviour.  They also secrete antimicrobial peptides to fight against bacterial infections.  The rib tips pick up a cocktail of poisons from the newt’s skin, and the poison is pulled back into the body along with the ribs.  The newts do not appear to be affected by their own toxic secretions suggesting that they are immune to it just as other newt species are to their own toxins.