Herpetology Notes

Herpetology Overview

  • Course Information
    • Dr. Jason R. Bohenek, ENV 320B
    • Lecture MWF 11:00 - 11:50
    • Lab W 1:00 - 3:50pm
    • MS Teams: @Bohenek, Jason

Behavioral Ecology Chapter 8: Key Objectives

  • Understand reasons for animal movement
  • Comprehend herpetological communication
  • Learn foraging strategies
  • Grasp predator avoidance techniques

Local Distributions: Home Ranges

  • Home Range Definition: Area an individual regularly occupies without defending from others
  • Influenced by:
    • Species and sex
    • Body size
    • Population density
  • Estimation Methods: Minimum polygons (convex hulls)

Home Range Characteristics

  • 3D Space Use: Variations noted in aquatic and terrestrial environments
  • Fossorial species: Tiny home ranges
  • Migrations for breeding not included in home range estimates

Home Range Variations

  • Microhabitat shapes affect home range shape
  • Seasonal changes alter range sizes (e.g., male breeding ranges increase)

Territories

  • Territory Definition: Defended area within home range
  • Criteria: Fixed area, defended behaviors, exclusive use by resident
  • Territorial behaviors: Aggressive displays, vocalizations, pheromones

Movement and Migration Patterns

  • Most herps have limited lifetime movement
  • Movement drivers: Breeding, foraging, environmental changes
  • Diurnal vs nocturnal behavior varies by species

Dispersal and Orientation

  • Dispersal: Undirected movement, usually by juveniles
  • Homing: Ability to return to specific locations
  • Orientation: Determining direction using environmental cues
  • Methods: Chemical, visual, polarized light, magnetic orientation

Key Mechanisms of Homing

  • Some salamanders can home several kilometers; turtles vary (some > 500 km)
  • Evidence of using polarized light for navigation observed in certain species (e.g., Trachemys scripta)

Conclusion

  • Understanding movement and territoriality in herps provides insights into their ecology and behavior.
  • These factors are crucial for conservation efforts, especially considering habitat changes and migratory challenges.