Webby's+Corner+8_12_2011

While both male and female platypuses are born with ankle spurs, only the male has spurs which produce a cocktail of venom, [|[23]] [|[24]] [|[25]] composed largely of [|defensin] -like [|proteins] (DLPs), three of which are unique to the platypus. [|[26]] The defensin proteins are produced by the immune system of the platypus. Although powerful enough to kill smaller animals such as dogs, the venom is not lethal to humans, but is so excruciating that the victim may be incapacitated. [|[26]] [|[27]] [|Oedema] rapidly develops around the wound and gradually spreads throughout the affected limb. Information obtained from [|case histories] and anecdotal evidence indicates that the pain develops into a long-lasting [|hyperalgesia] (a heightened sensitivity to pain) that persists for days or even months. [|[28]] [|[29]] Venom is produced in the [|crural] glands of the male, which are kidney-shaped [|alveolar glands] connected by a thin-walled duct to a [|calcaneus] spur on each hind limb. The female platypus, in common with echidnas, has rudimentary spur buds which do not develop (dropping off before the end of their first year) and lack functional crural glands. [|[11]] The venom appears to have a different function from those produced by non-mammalian species: its effects are not life-threatening to humans but nevertheless powerful enough to seriously impair the victim. Since only males produce venom and production rises during the breeding season, it is theorised that it is used as an offensive weapon to assert dominance during this period. [|[26]]