Reptile Behavior and Ecology Notes

Territoriality and Male Competition

• Observations of male-male competition and territoriality among lizards.
• Larger males often are more successful in securing territories or mating opportunities.

Sexual Size Dimorphism in Reptiles

• The chart showing sexual size dimorphism (SSD) patterns in turtles, lizards, and snakes, with significance markers for bias.
  • X-axis: Indicates degree of size dimorphism.
  • Y-axis: Specific species observations.
  • Left side: Male-biased size dimorphism (males larger).
  • Right side: Female-biased size dimorphism (females larger).
  • No markers: Indicates no significant size differences.
• Most reptiles exhibit some bias toward either sex concerning body size at maturity.

Developmental Changes in Body Size

• Plessed on Latticept (Broadheaded Skink):
  • Both sexes start similarly in growth but diverge at sexual maturity.
  • Males develop larger head widths due to testosterone effects.

Reproductive Patterns Based on Body Size

• Example from Anulus carillonensis:
  • Data shows larger males mating with more females (up to 14) compared to smaller males (2-4).

Use of Scat in Behavioral Communication

• Scat can be used for:
  • Individual recognition among neighboring reptiles.
  • Territorial marking, particularly among species like Plethodon cinereus that pile scat in communal areas.

Foraging Ecology Overview

• Focus on dietary habits: understanding what herbivorous reptiles eat and how they capture prey.
• General guideline for most reptiles: they eat anything that fits in their mouths.
• Herbivores significantly impact prey populations and food webs, especially in warmer environments.

Dietary Habits by Reptile Groups

• Caecilians: Predominantly earthworms and invertebrates.
• Frogs and Salamanders: Mainly insects, occasionally small vertebrates.
• Crocodilians: Consume various vertebrates including mammals and fish.
• Turtles: Omnivorous; eat plants and animals.
• Squamates (lizards, snakes): Dietary habits correlate with body size; larger species tend to eat vertebrates.

Exceptions in Herbivory

• Certain lizard taxa, including Iguanidae and Leiolopididae, exhibit herbivorous behavior.
• Smaller-bodied species such as southern South American lizards may feed on fruits and flowers, especially in low-energy environments.

Foraging Modes

Categorization of Predators:

• Sit and Wait Predators (Ambush):
  • Minimal energy spent looking for prey; rely on prey abundance.
  • Types: e.g., Alligator snapping turtles use a lure for prey.
  • Advantages: Efficient energy use but risk fewer opportunities.
• Active Foragers:
  • Move to find prey; utilize visual and chemical cues.
  • Increased vulnerability to predation.
• Sit and Pursue: A debated category where predators ambush until prey is within reach before chasing.

Optimal Foraging Theory

• Animals should maximize energy gained from prey for efficiency.
• Many animals do not forage optimally due to:
  • Environmental uncertainties and conflicting demands.
  • Reproductive and predation risks.
• Evidence suggests when food is scarce, animals will diversify their diet more than when food is abundant.

Differences in Foraging Behavior

• Specific studies indicate sexual dimorphism in foraging behaviors. For instance, male Acrochordus arafuri actively searches shallow water for small fish, while females ambush larger fish in deeper waters.
• Factors affecting foraging behavior:
  • Foraging mode, sensory capabilities, body size, biomechanics, and time of day.