Hedgehogs Use Toad Venom For Defense
European hedgehogs chew toad skins to extract venom from the paratoid glands. They then lick their spines with the saliva-venom mixture. Experiments with human volunteers prove that the venomanointed spines are much more painful and irritating than clean ones. Such hedgehog behavior is innate and fully developed before the juveniles leave the nest. Tenrecs, which are similar to hedgehogs but in an entirely different family, display a somewhat different self-anointing type of behavior that must have developed independently. Conclusion: self-anointing with toad venom is so useful that it developed twice under evolutionary pressures.
(Brodie, Edmund D., Jr.; "Hedgehogs Use Toad Venom in Their Own Defense," Nature, 268:627, 1977.)
Reference. Hedgehog anointing and other idiosyncrasies may be found in Chapter BMB in Biological Anomalies: Mammals I. This book is described here.