can hibernate, though not all do, depending on temperature, species, and abundance of food. Hedgehogs are fairly vocal and communicate through a combination of grunts, snuffles and/or squeals, depending on species. Hedgehogs occasionally perform a ritual called anointing. When the animal encounters a new scent, it will lick and bite the source, then form a scented froth in its mouth and paste it on its spines with its tongue. The purpose of this habit is unknown, but some experts believe anointing camouflages the hedgehog with the new scent of the area and provides a possible poison or source of infection to predators poked by their spines. Anointing is sometimes also called anting because of a similar behavior in birds. Like opossums, mice, and moles, hedgehogs have some natural immunity against some snake venom through the protein erinacin in the animal's muscular system, although it is available only in small amounts and a viper bite may still be fatal. In addition, hedgehogs are one of four known mammalian groups with mutations that protect against another snake venom, α-neurotoxin. Pigs, honey badgers, mongooses, and hedgehogs all have mutations in the nicotinic acetylcholine receptor that prevent the snake venom α-neurotoxin from binding, though those mutations developed separately and independently. Olfactory sense The olfactory regions have not been thoroughly studied in the hedgehog. In mammals, the olfactory part of the brain is covered by neopallium, making it difficult to expose. This difficulty is not insurmountable, as it varies from one species to another. Tests have suggested that hedgehogs share the same electrical activity as cats. Diet Although traditionally classified in the now abandoned order Insectivora, hedgehogs are omnivorous. They feed on insects, snails, frogs and toads, snakes, bird eggs, carrion, mushrooms, grass roots, berries, melons and watermelons. Berries constitute a major part of an Afghan hedgehog's diet in early spring after hibernation. Hibernation During hibernation, the body temperature of a hedgehog can decrease to about . When the animal awakes from hibernation, the body temperature rises from back to its normal body temperature. Reproduction and lifespan Depending on the species, the gestation period is 35–58 days. The average litter is 3–4 newborns for larger species and 5–6 for smaller ones. As with many animals, it is not unusual for an adult male hedgehog to kill newborn males. Hedgehogs have a relatively long lifespan for their size. Larger species of hedgehogs live 4–7 years in