Antipredatory Function of Head Shape for Vipers and Their Mimics
2011

Head Shape of Vipers and Their Mimics

Sample size: 595 publication Evidence: moderate

Author Information

Author(s): Janne K. Valkonen, Ossi Nokelainen, Johanna Mappes

Primary Institution: University of Jyväskylä

Hypothesis

Does the triangular head shape typical of vipers offer protection against predation?

Conclusion

The triangular head shape of vipers acts as a warning signal to predators, reducing the likelihood of attacks.

Supporting Evidence

  • Plain snakes with narrow heads suffered significantly higher predation by raptors than snakes with triangular-shaped heads.
  • Head shape did not have an additive effect on survival in zigzag-patterned snakes.
  • 8.2% of the snake replicas were attacked by raptors and 18.5% by mammalian predators.

Takeaway

Vipers have a special head shape that helps them avoid being eaten by birds. Other snakes can copy this shape to stay safe too.

Methodology

The study used artificial snake replicas to compare predation pressure on different head shapes and body patterns.

Potential Biases

Potential bias due to the artificial nature of the models and their olfactory cues affecting predator behavior.

Limitations

The use of plasticine models may not accurately represent real snakes, particularly for mammalian predators that rely on smell.

Statistical Information

P-Value

p=0.010

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0022272

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