Hedgehogs vs snakes
Snakes represent formidable prey for many predators and there is much in the popular and scientific literature about how hedgehogs handle adders (Vipera berus). The adder’s venom is generally less potent than that of other viper species (cf. the chain viper, Daboia russelii) and delivered in lower quantities; its proteolytic activity makes it potentially lethal to the victim, nonetheless. Nigel Reeve amalgamates several sources in Hedgehogs to provide a description of an encounter between these species.
According to Reeve, upon meeting an adder the hedgehog will bristle its spines and draw them down to cover its snout and legs; part of this motion causes the spines to bunch up over its head. The hedgehog then approaches and attempts to bite along the snake’s body. Invariably, the snake responds by trying to bite the hedgehog. Adder fangs are solenoglyphous; they’re hollow, located at the front of the mouth and are hinged such that they are erected when the mouth is opened. In his study of viper fang lengths, published in the Journal of Herpetology in 1982, Chris Ernst noted that the fangs of adult V. berus are a maximum of 4mm (just over one-tenth of an inch) long; i.e. the hedgehog’s spines are about 60 times longer than the adder’s fangs. Consequently, the snake’s bite comes nowhere close to the hedgehog’s skin all the time the spines are drawn down.
In cases where hedgehogs have been bitten by snakes the response is variable; from no observable reaction, to death. In June 2014, Israeli wildlife photographer “Tevaironi” observed a fight between an eastern hedgehog (Erinaceus concolor) and a small Palestine viper in the Ashkelon area of the country during which the snake bit the hedgehog - both died. Similarly, in the late 1800s, Césaire Phisalix and Gabriel Bertrand observed that injection of adder venom into a small hedgehog proved fatal, although at a dose about 40-times greater than was required to kill a guinea-pig. A series of experiments by German reptile biologist Wilhelm Schreitmüller that make rather uncomfortable reading investigated adder venom on captive hedgehogs. The study, published in the German journal Blätter für Aquarien und Terrarienkunde in 1909, found that two healthy hedgehogs died two or three hours after being bitten on the head by an adder. Nonetheless, biochemical assays of hedgehog muscle plasma have yielded a macroglobulin proteinase inhibitor called erinacin, which appears to neutralize the haemorrhagic (blood vessel rupturing) activity of venom of at least ten species of snake; reported in two papers to Toxicon, one in 1994 the other in 1996.
That snake bites can be fatal to some hogs but not to others suggests any ‘immunity’ to venom is either incomplete or individually variable. Indeed, in the 1996 paper to Toxicon, Dietrich Mebs and his co-workers reported that dissociation of erinacin (i.e. breaking it into its subcomponents) resulted in a complete loss of its antihaemorrhagic activity.
Snake venom is apparently not the only toxicant that is less effective against hedgehogs. Several species of beetle that secrete distasteful chemicals when disturbed or attacked are still eaten by hogs. Oil beetles (Meloe) and the appropriately-named blister beetles (Lytta) secrete cantharidin, a type of lipid called a terpenoid that can cause urinary tract irritation and genital swelling; it can also be toxic to humans. Cantharidin is given to the female beetle during mating by the male and is used to cover the eggs, thus protecting them from predators; in human medicine, when diluted it can be used to treat warts and remove tattoos. When Lytta or Meole beetles are attacked, they secrete cantharidin, but hedgehogs apparently ignore it. While feeding, hedgehogs also seem to pay little attention to the melittin in apitoxin (bee venom), the mastoparan in wasp venom or the stinging bites of ants.
Carrying fruit on spines
I think most hedgehog biologists, and probably some hog fans, have at some point attempted to make an apple stick on the spines of their subject. As a child, in 1988, I remember Sir Peter Scott’s regimental narration of the Anglia TV Junior Survival episode The Truth about Mrs. Tiggywinkle, in which film-maker Elizabeth Bomford managed to impale a small, soft apple on the spines of one of their stars – the golf ball sized fruit remained attached for a few seconds, until the walking motion of the hedgehog dislodged it a few metres from where it had been impaled. Nigel Reeve wrote of how Pat Morris tried a similar experiment during the BBC’s The Great Hedgehog Mystery in 1982, with comparable results.
Given that caching of food has never been observed in European hedgehogs (the Indian hedgehog, Paraechinus micropus, is known to take food back to its burrow for later consumption, incidentally), that food is not taken back to the nest for young, and that even items used as nesting material are carried in the mouth, makes intentional carrying off of apples or other fruit in this way seem unlikely. Stories have nonetheless persisted since at least Ancient Roman times. The writings of Pliny the Elder in Historia Naturalis, for example, tell of hedgehogs climbing trees to dislodge fruit before dropping on to them and trotting off with their impaled prize. Similarly, a brief piece to the journal Folklore in 1917 by Mabel Peacock told how a several people had “a clear view” of a hedgehog with apples stuck on its spines in a local orchard. Maurice Burton, in his 1969 book The Hedgehog, recounted several reports he had received of hedgehogs apparently removing fallen fruit, including one that was apparently watched over several nights carrying away four to six at a time on its spines to an old tree stump where the observers found 20 to 30 stashed apples.
In many examples, the hedgehogs appear to collect the fruit into a small pile before rolling onto them. Similar accounts exist of them carrying away strawberries and grapes, and even one of a captive individual impaling a beetle on its spines. The most reasonable hypothesis presented thus far for impaled fruit is that hedgehogs may be stimulated into self-anointing (see Behaviour and Social Structure) by its presence. Burton himself observed a half-grown captive hog to impale crab apples while in the throes of self-anointing, but many other observations have failed to elicit self-anointing in the presence of fruit. Similarly, there are many reports of hedgehogs throwing themselves on their backs in apparent tantrum, but the accounts suggest a deliberateness to the fruit impaling. Sufficed to say, the behaviour has never been filmed and I’m aware of no recent reports. As such this behaviour is widely dismissed today, the suggestion being that carrying off fruit on the spines is at best a purely accidental affair; but, given the number of account and their wide distribution, such accounts should not be dismissed out of hand.
Suckling from cows
Despite hedgehogs being lactose intolerant, they will readily consume cow’s milk and, in his Complete Hedgehog, Les Stocker suggests that people who have reported hedgehogs ‘suckling’ from cows may have actually observed a hedgehog lapping at milk leaking from an udder. Indeed, Oliver Pike is more damning of reports suggesting hedgehogs take milk from cows, referring to them as ‘slander’ in his Wild Animals of Britain. Pike is clear in his belief that these stories represented nothing more than superstition, writing:
“Quite the worst [superstition] is the idea that it will take milk from cows as they rest on the ground at night; nothing could be more ridiculous.”
There is a report, however, of a farmer finding a hedgehog attached to the udders of a dairy cow – in this particular case, the cow kicked the hedgehog off and the farmer killed it. This was, as far as I know, the only account of hedgehogs biting cow’s udders that has made it into the scientific literature. It appeared as a brief note to Veterinary Review in 1969 and described the hedgehog having left shallow, longitudinal incisions on either side of the udder teat.
Interestingly, two articles appeared in the same journal a couple of years before this, one in May and one June 1967, describing similar lacerations to cow teats and noting that such damage occurs only during spring and summer, when hedgehogs are most active. These bite marks have led to the suggestion that, rather than suckling from the cow, the hedgehog might actually have been trying to eat the udder! We don’t know for certain, but Reeve cites the case of a hedgehog attached to the udder of a sheep in Hedgehogs and, in their Natural Hedgehog, Lenni Sykes and Jane Durrant reject the theory of suckling, noting that adult hedgehogs cannot actually suckle.
Konrad Herter observed one of his captive hedgehogs standing on its hind legs in what he referred to as a bipedal stance and suggested that the animal was able to hold the position long enough to have grabbed an udder teat had a cow been present. Similarly, in The Hedgehog, Maurice Burton quotes a letter published in the Hereford Times in March 1959 in which a farmer described how he got up early to check on a Jersey cow that had started giving less milk in the mornings:
“Creeping quietly through the orchard I found the cow lying down under a tree round which was a great wood pile and there, sucking away and having a grand breakfast, were two hedgehogs.”
Perhaps more interestingly, Burton also recounts an ad hoc experiment conducted by Stéphanie Ryder who rigged up a calf feeding teat in her house and introduced one of the wild hedgehogs that visited her garden to it. Recalling a letter Ryder sent him, Burton wrote:
“The hedgehog without hesitation went over to the teat and ‘as if by instinct’ seized the teat in its mouth, set back on all fours tugging at the teat and allowing its teeth to travel down the teat. In this way it emptied the teat of milk with an action directly comparable with our hand-milking a cow.”
According to Burton, Ryder repeated this experiment with the same result.
Whatever the reason behind hedgehogs being found around cow udders, the problem was apparently a serious one in the past. Stocker described how some medieval Britons would leave a bottle of home-brewed beer and a piece of cake out for the ‘farming fairy’ Old Nancy, who they believed could prevent hedgehogs from taking milk from their cows. If Old Nancy failed, hedgehogs were slaughtered in great numbers. Similarly, Stocker notes that Irish people often considered hedgehogs to be “Graineeogs” (“ugly ones”) that were witches in animal form; not only did they suckle from cows, but they also bewitched the livestock and caused their milk to dry up.