predators. The tightly coiled animal will raise the last several inches of its tail, this portion often being bright yellow or green in juveniles and a faded yellow or green in adults, the animal will then tail vibrate, creating a loud whipping sound against its coils or surroundings. This particular behavior is very reminiscent of caudal luring, though in a more violent fashion and is often accompanied by a strike or less commonly a gaping display similar to that of A. piscivorus. They generally will only display these behaviors when given no other choice. In captivity, A. bilineatus are often known for aggression stemming from their characteristic lack of predictability. Reproduction Breeding occurs in the spring, and like most other viper species, cantils are ovoviviparous, giving birth to 5–20 young at a time. Captivity Export from Mexico is not permitted, but cantils of both species are often captive-bred, making them frequently available in the exotic pet trade. They are also well represented in zoos throughout North America and Europe. Venom According to Gloyd and Conant (1990), "this species is greatly feared throughout its range," in some areas even more so than Bothrops asper. In Sonora, Mexico, it is feared more than any other reptile. In Nicaragua, it is considered the country's most dangerous snake. Bite symptoms, in general, may include nothing more than local pain, swelling and discoloration, but those from adult specimens can cause massive swelling and necrosis. Campbell and Lamar (1989) suggested that, due to the necrosis, amputation may be required in one out of every six cases. Some bites were fatal within only a few hours. Gaige (1936) cites one case in which a woman in Motul, Yucatán, Mexico was bitten by a specimen and died within a few hours. Alvarez del Toro (1983) reports gangrenous tissue falling away in fragments, eventually to expose the underlying bones, describing this is as "spontaneous amputation" of the necrotic wound. In Honduras, Cruz (1987) describes the bite symptoms as being similar to those of Bothrops species, although more severe considering the small size of these snakes. They include immediate and severe pain, oozing of blood from the fang punctures, considerable edema, nosebleed, bleeding of the gums, marked hematuria, general petechiae, shock, kidney failure and local necrosis. Polyvalent Antivenom, produced by the Instituto Clodomiro Picado Taxonomy A new subspecies, A. b. lemosespinali, was described by H. M. Smith & Chiszar (2001)