Unexpected lack of specialisation in the flow properties of spitting cobra venom

ABSTRACT Venom spitting is a defence mechanism based on airborne venom delivery used by number of different African and Asian elapid snake species (‘spitting cobras’; Naja spp. Hemachatus spp.). Adaptations underpinning have been studied extensively at both behavioural morphological level in cobras, but the role physical properties itself its effective projection remains largely unstudied. We hereby provide first comparative study non-spitting cobras. measured viscosity, protein concentration pH 13 cobra genus from Africa Asia, alongside haemachatus viper Bitis arietans. By using published microCT scans, we calculated pressure required to eject through fangs cobra. Despite differences modes delivery, found no significant between spitters non-spitters rheological venoms. Furthermore, all analysed venoms showed Newtonian flow behaviour, contrast previous reports. Although our results imply that evolution did not significantly affect models fang suggests requirements are lower cobras than