title: Does the rattle of Crotalus durissus terrificus reveal its dietary history?
abstract: BACKGROUND
  Environmental devastation threatens the survival of many species, including venomous snakes such as the South American rattlesnake Crotalus durissus terrificus. This observation is based on the decrease of snakes collected and donated to Brazilian research institutes. Nevertheless, some individuals have managed to survive and procreate. The question is how these snakes are adapting in these new environmental conditions.
  
  
  METHODS
  To answer it, the carbon-13 level of rattlesnakes and their feed (either laboratory or wild mice) was evaluated by isotope-ratio mass spectrometry. Thus, rattle segments from 16 adults and 15 offspring of captive snakes, and of three wild newborn C. d. terrificus were evaluated as well as 17 Mus musculus mice captured in traps, four live feeder mice and the ration offered to mice at animal houses.
  
  
  RESULTS
  The isotopic exchange time of the captive adult snakes (n = 16) varied between 33 and 37 months and of captive-born animals (n = 15), until reaching a plateau of equilibrium, varied from 18 to 24 months. Regarding the captured Mus musculus (n = 17), 88.23% (n = 15) were from a C4 environment. Of the six rattle rings from offspring of captured C. d. terrificus, five were from a C4 environment, whereas of the 170 rattle rings studied, 60% originated from a C3 environment and 40% from a C4. The same carbon-13 values were found in captive snakes.
  
  
  CONCLUSIONS
  Based on the present results, it can be inferred that most C. d. terrificus snakes (60%) fed animals from a C3 environment; birds consist of an alimentary alternative for snakes, as well as rodents, small reptiles and amphibians; different venom compositions among snakes from the same region may be related to the food type; the primary rattle of offspring reflects the maternal diet during gestation; and, finally, the different rattle rings indicate the alimentary history of these animals.
authors.affiliation: Center for the Study of Venoms and Venomous Animals, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, São Paulo State Brazil.
authors.forename: Melissa Gaste
authors.initials: MG
authors.lastname: Martinez
authors.affiliation: Stable Isotopes Center (CIE), Botucatu Biosciences Institute, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, São Paulo State Brazil.
authors.forename: Carlos
authors.initials: C
authors.lastname: Ducatti
authors.affiliation: Stable Isotopes Center (CIE), Botucatu Biosciences Institute, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, São Paulo State Brazil.
authors.forename: Evandro Tadeu
authors.initials: ET
authors.lastname: Silva
authors.affiliation: Laboratory of Herpetology, Butantan Institute, São Paulo, São Paulo State Brazil.
authors.forename: Savio Stefanini
authors.initials: SS
authors.lastname: Sant'Anna
authors.affiliation: Stable Isotopes Center (CIE), Botucatu Biosciences Institute, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, São Paulo State Brazil.
authors.forename: Maria Márcia Pereira
authors.initials: MM
authors.lastname: Sartori
authors.affiliation: Center for the Study of Venoms and Venomous Animals, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, São Paulo State Brazil ; Botucatu Medical School, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, São Paulo State Brazil ; CEVAP/UNESP, Rua José Barbosa de Barros, 1780, Fazenda Experimental Lageado, Botucatu, SP CEP 18610-307 Brazil.
authors.forename: Benedito
authors.initials: B
authors.lastname: Barraviera
keywords: Carbon-13; Crotalus durissus terrificus; Food; Stable isotopes