Scientists have given us a glimpse into the incredible world of spider mating.

Researchers from Slovenia recently examined the sexual behavior of the Darwin's Bark Spider, Caerostris darwini, a dimorphic species from Madagascar. They revealed that these arachnids' sexual repertoire includes oral sex.

Darwin's bark spider, named in honor of Charles Darwin, creates the world's biggest, strongest spider webs. An article published in National Geographic notes that Zoologist Ingi Agnarsson and colleagues have found Darwin's bark spider webs as wide as 82 feet (25 meters)-about as long as two city buses in 2009.

During a two-week monitoring, lead researcher Matjaz Gregoric, research associate at the Scientific Research Centre of the Slovenian Academy of Sciences and Arts, together with his team of experts found to their surprise that males, who are 14 times smaller than the gigantic females, routinely salivate onto female genitalia - pre-, during, and post-copulation.

"Oral sexual contact seems to be an obligate sexual behaviour in this species as all males did it before, in between, and after copulation, even up to 100 times," said Gregoric in a news release.

Aside from oral sex, the group also observed "sexual cannibalism," in which some females consume the males after mating, "post-mating emasculation," where males bite off a portion of their own sex organs within 24 hours of sex, "opportunistic mating" where males would mate with females while exoskeleton is still soft and "mate binding," in which the giant female was extensively bound in silk to prevent her from eating the male at any point during sex.

According to the report published in Journal Scientific Reports, the researchers were mostly surprised to witness oralsex in spiders, as this kind of behavior is rarely reported outside mammal.

Daily Mail reports that ‘fellatio-like' behaviors have been observed in macaques, lemurs, bonobos, hyenas, cheetahs, lions, dolphins, and bats.

The team speculates that this type of sexual behavior may work to boost the chances of paternity by or creating an environment that would favor one male's sperm against the sperm of rival males.

They also suggest it may be a means of cannibalism avoidance. However, it seems to be an unlikely function since male do it in all females, regardless of their aggressiveness.

While the two theories are intriguing the researchers also suggest testing outside of the scope of the report to gather more information.