The defensive strike of five species of lanceheads of the genus Bothrops (Viperidae)

Abstract

We studied the defensive strike of one species of each of five recognized lineages within the genus Bothrops, namely, B. alternatus, B. jararaca, B. jararacussu, B. moojeni and B. pauloensis. The defensive strike of the studied species was in general similar to that of Crotalus viridis and C. atrox, but some important differences were observed. Bothrops alternatus and B. pauloensis struck preferentially from a tight body posture, whereas B. jararaca and B. moojeni from a loose body posture. Defensive strikes were either true or false (during the latter, the mouth remains closed or partially open). Almost all strikes were successful; only on a few occasions snakes missed their target (flawed strikes). Strike variables were very conservative among the five species, especially strike distance and height, and one possible explanation may be related to constraints imposed on strike variables as a way of increasing strike accuracy.Keywords: lanceheads, Bothrops, Viperidae, defensive behavior. O bote defensivo de cinco espécies de jararacas do gênero Bothrops (Viperidae) ResumoEstudamos o bote defensivo de uma espécie de cada uma de cinco reconhecidas linhagens do gênero Bothrops, a saber: B. alternatus, B. jararaca, B. jararacussu, B. moojeni e B. pauloensis. O bote defensivo das espécies estudadas foi, em geral, semelhante ao de Crotalus viridis e C. atrox, porém algumas diferenças foram observadas. Bothrops alternatus e B. pauloensis desferiram botes preferencialmente a partir de postura corpórea enrodilhada, ao passo que B. jararaca e B. moojeni desferiram a maioria dos botes a partir de postura corpórea frouxa. Os botes defensivos foram verdadeiros ou falsos (nestes, a boca da serpente permaneceu fechada ou parcialmente aberta). Quase todos os botes foram bem-sucedidos; apenas em alguns casos a serpente errou o alvo (botes falhos). As variáveis relativas aos botes foram bastante conservativas entre as cinco espécies, principalmente distância e altura do bote, e uma possível explicação pode estar relacionada a restrições impostas às variáveis relativas aos botes como forma de aumentar sua acurácia.Palavras-chave: jararacas, Bothrops, Viperidae, comportamento defensivo.

Strike kinematics and performance in juvenile ball pythons (Python regius)

“…Recently, work by Penning, Sawvel, and Moon () found similarly explosive accelerations and high performance in striking by adult Texas ratsnakes ( Pantherophis obsoletus ) when directly compared with two pitvipers ( Agkistrodon piscivorus and Crotalus atrox ), shifting the paradigm on how we think of strike performance in snakes. All of the strikes were in a defensive context, but levels of performance were equivalent to other vipers striking in a feeding context, and at least one other study has noted the similarity in performance between feeding and defensive strikes (Araújo & Martins, ; LaDuc, ). Comparisons between the two, then, are not without merit, and are indicative of the maximum performance of an individual snake.…”

Debunking the viper's strike: harmless snakes kill a common assumption

“…(covariate-adjusted mean in parentheses). Other data are means except for medians of best-performance values from five Bothrops species [11]; emdashes indicate no data. Trimeresurus albolabris values are composite means from male and female means [2].…”

“…¼ 348 + 71 g, snout -vent length ¼ 91 + 5.6 cm), 6 western cottonmouth vipers (Agkistrodon piscivorus; 273 + 15.8 g, 68 + 2.4 cm), 12 western diamond-backed rattlesnakes (Crotalus atrox; 634 + 38 g, 95 + 2.0 cm) and previously published studies [2,4,10,11]. We discuss the accelerations of snake strikes in relation to the known physiological effects experienced during high accelerations, and we compare strike durations with mammalian startle-response times.…”

New records and notes on defensive behavior of Thamnodynastes rutilus (Prado 1942)

“…Strike with bite and cloacal discharge were recorded only during the animal manipulation, and possibly is an extreme defensive mechanism to discourage their ingestion by the predator (Tozetti et al, 2009), suggesting that this species is able to adjust their defensive behavior according to the threat level imposed by the predator. Still, the pattern of cryptic coloration and the defensive behavior repertoire (head triangulation, false strike, S-shape posture and elevation of the anterior portion of the body) similar to that described for the genus Bothrops (Sazima, 1988;Araújo and Martins, 2006) suggests that T. rutilus mimics sympatric species of this genus. Other similar cases among colubrid species mimicking viperids or elapids based on the similarity of the color patterns and behavior have been reported (Gans and Latifi, 1973;Sánchez-Herrera et al, 1981;Yanoski and Chani, 1988;Marques and Puorto, 1991), and experiments using models mimicking dangerous species showed that in most cases, such characteristics prevent predators from striking (Dell'Aglio et al, 2012).…”