Rattlesnakes are native to the Sonoran Desert. As spring approaches, the venomous reptiles become more active and this means more encounters with humans and animals.    Due to the curious nature of horses, they often investigate new or strange objects with an outreached muzzle for a quick sniff.  This innocent gesture towards a venomous snake often results in a defensive strike from the reptile.  Mature rattlesnakes have voluntary control of the amount of venom they may deposit.  This volume depends on the size of prey, time of year, or if the strike is under defensive conditions.  Not all snake bites result in envenomation.
     Snake venom is composed of a highly complex mixture of toxic compounds all serving and aiding in the capture, decomposition, and digestion of its prey.  Due to the size of horses this rarely results in death.     There is generally severe local tissue swelling with secondary tissue infections. 
     Humans can breathe through their mouth or nose unlike horses who are obligate nose breathers. Horses have no other means of inspiring air.  Therefore, a strike to the muzzle can severely impair a horse’s ability to breathe.
     A bite to the nose often requires a tracheotomy to open an airway.  If one is not near immediate medical attention and the horse’s airway is closing one may use a small 6-8 inch long piece of rubber hose or a 12cc syringe case opened on both ends gently inserted in the nasal passages as a means of maintaining an airway.  It is important not to panic nor excite the horse in a way that would increase its respirations as this would make it more difficult for them to breathe. All horses that have been bitten by a snake or with signs of a potential bite should be seen by a veterinarian.