In conjunction with scent, vocalization appears to play a key role in social interaction. In his Badgers' Year, Howard Lancum talks about badgers making “a great variety of interesting and characteristic noises” that, once familiar, are unmistakable.
Lancum goes on to describe the boar's “weird, unearthly scream, sometimes heard in early spring or late autumn, which is calculated to raise 'gooseflesh'”. He notes that this scream is often considered associated with sexual excitement, although several of his examples doesn't seem to tie in with breeding season, suggesting it may be a more general call, possibly acting as a warning or territorial challenge. Boars also described as making “purring” or “crooning” noises while courting sows, while females make a “muttering, warning growl” when trying to restrain over-eager cubs and a much softer whickering noise when calling them out of the sett. During bouts of play, badgers old and young will growl and yelp akin to a dog, and sometimes “spit rather like a cat but much more decidedly”. One badger cub apparently gave a single “yelp of joy or excitement” upon finding something particularly good to eat.
Lancum also heard his study subjects emit a “staccato chattering after the manner of a stoat” and a “moaning whine, made with closed jaws” that he associated with real anger, a warning to all concerned that the badger meant business—in one case while evicting a fox from the sett. He reported a curious noise that was “not a grunt, a cough or sneeze, but seemed to have in it something of all three” uttered by a badger before backing slowly down into the sett. Finally, he described the “violent, explosive belch following acute alarm or disgust”, the kind, Lancum proposes, that would've delighted French Renaissance writer François Rabelais. This “gloriously vulgar noise” is sometimes accompanied by a pungent discharge from the badger's scent gland, Lancum noted.
More recently, in a fascinating paper to the Journal of Mammalogy, David Macdonald, Paul Stewart and Josephine Wong described a range of calls recorded during their observation of the badger setts in Wytham Woods. The researchers could identify 16 calls: bark, chirp, chitter, churr, cluck, coo, growl, grunt, hiss, kecker, purr, snarl, snort, squeak, wail, and yelp. A description of the calls and details of when they're made can be found on the Badgerland website. The original sound files (originally hosted on the WildCRU site) are no longer available for download, but WildCRU have put together a video of the calls (see below).
The churr of a badger. This insistent, throaty vibration appears to be a mating call. - Credit: Adele Brand
A badger "gekkering" at another clan member when it encroaches on its feeding area. - Credit: Alan Baldry
A badger "squeaking" at another clan member when it encroaches on its feeding area. - Credit: Alan Baldry
In the paper, Macdonald and his colleagues write that churrs, purrs and keckers are restricted to adults; chirps, clucks, coos, squeaks and wails to cubs; while the remaining eight calls were exhibited by both. In his 1975 opus, Grzimek's Animal Life Encyclopaedia, the late German zoologist Bernhard Grzimek described a “piercing scream” that is apparently emitted by wounded badger. Grzimek writes:
“This call [referring to a call reported during badger copulation] resembles the death scream of a mortally wounded badger, a sound which is so terrifying that many a hunter has ceased getting badgers after hitting one and hearing the cry.”
While the WildCRU biologists were able to link the acoustic structure of the calls they witnessed to their function, which they inferred from the context in which the call was made, they found no evidence for either alarm calls to conspecifics or the long-range “scream” to which Grzimek refers. Given the absence of loud (and thus long-distance) calls, it is reasonable to assume that vocalization is probably an inherently interpersonal form of communication that is used on a strictly close-range basis (i.e., between individuals in close quarters). Furthermore, the vocalisations are context-specific, such that the body language of the badger and the situation can result in the same sound (to our ears) having different meanings. In Badgers of Yorkshire and Humberside, for example, Adrian Middleton and Richard Pagent described adult badgers purring while mating, while interacting with cubs and while collecting bedding.