Research ArticleECOLOGY

When males live longer: Resource-driven territorial behavior drives sex-specific survival in snakes

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Science Advances  24 Apr 2019:
Vol. 5, no. 4, eaar5478
DOI: 10.1126/sciadv.aar5478
  • Fig. 1 Number of individual kukri snakes (O. formosanus) captured annually at our study sites.

    Snakes captured in (A) Little Paiday Bay (where sea turtles nested throughout our study) and (B) Tungching (where sea turtles nested from 1997 to 2000, and nests were absent from 2001 to 2012), shown separately for adults and juveniles. Arrow indicates that a severe storm eroded the beach.

  • Fig. 2 Means ± SD of kukri snakes (O. formosanus) body mass increase per day at our Little Paiday Bay (1997–2007) and Tungching (1997–2000) study sites in Orchid Island, Taiwan.

    Lowercase letters summarize the results of pairwise multiple comparisons.

  • Fig. 3 Ratios of injuries incurred by male and female kukri snakes (O. formosanus) at Little Paiday Bay (where sea turtles nested throughout our study) and Tungching (where sea turtles nested from 1997 to 2000, and nests were absent from 2001 to 2012), shown separately by sex.

    Lowercase alphabets summarize the results of pairwise multiple comparisons among location-year groups. Numbers inside the parentheses present the denominators (total number of observed sea turtles).

  • Fig. 4 Survival rates and estimated life span of male and female kukri snakes (O. formosanus) at Little Paiday and Tungching.

    Annual apparent survival rates (A) were calculated using mark-recapture analysis, and life-span estimates (B) are based on these survival rates. Data are shown for Little Paiday (sea turtles nested throughout our study), Tungching (sea turtles nested in 1997–2000 but were absent in 2001–2012), and laboratory-raised snakes from 1997 to 2015. NS, not significant. *P < 0.05.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/4/eaar5478/DC1

    Fig. S1. Territorial behavior of female snakes in Orchid Island, Taiwan.

    Fig. S2. Photos of injury in snakes.

    Table S1. Fitting numbers of adult kukri snakes against years and sites.

    Table S2. Fitting numbers of juvenile kukri snakes against years and sites.

    Table S3. Refitting numbers of adult kukri snakes against three-level years and sites.

    Table S4. Refitting numbers of juvenile kukri snakes against three-level years and sites.

    Table S5. Multiple comparisons of snake body mass increase among sites and sexes.

    Table S6. Fitting injury ratios among sites, years, and sexes.

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Territorial behavior of female snakes in Orchid Island, Taiwan.
    • Fig. S2. Photos of injury in snakes.
    • Table S1. Fitting numbers of adult kukri snakes against years and sites.
    • Table S2. Fitting numbers of juvenile kukri snakes against years and sites.
    • Table S3. Refitting numbers of adult kukri snakes against three-level years and sites.
    • Table S4. Refitting numbers of juvenile kukri snakes against three-level years and sites.
    • Table S5. Multiple comparisons of snake body mass increase among sites and sexes.
    • Table S6. Fitting injury ratios among sites, years, and sexes.

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    Files in this Data Supplement:

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