Module 2: Animal Signs and Impressions
Introduction to Animal Impression Evidence
Focus on animal impression evidence, primarily animal sign.
Not all animal signs are considered impressions.
Indicates the need to distinguish between relevant and irrelevant signs.
Encouraged to take a dedicated course on animal tracks and signs.
Importance of understanding animal sign in crime scene investigation contexts.
Definition of Impression Evidence
Impression evidence is defined as:
Objects or materials retaining characteristics of other objects through direct physical contact.
Examples of impression evidence include:
Fingerprints
Footwear impressions
Tire impressions
Bite marks
Gorilla nose prints
Whisker print analysis
A number of readings provided on this topic, showcasing the various disciplines related to animal impression analysis.
Early Forms of Impressions
The earliest forms of impressions include:
Plant and animal fossils.
Features recorded when pressed into rock and soil.
Example photo shows:
Animal tracks alongside tire marks.
Importance of Understanding Animal Sign in Crime Scenes
Animal sign is defined as:
Physical evidence of disturbances in the environment left by animals (human or non-human).
Examples include:
Tire marks
Detection of animal sign is referred to as "sign cutting", emphasizing the tracking of disturbances made during movement.
Benefits of understanding animal sign:
Assesses wildlife crime scenes.
Helps identify the type of animal involved.
Aids in tracking possible criminals.
Assists in establishing crime scene perimeters.
Facilitates understanding of how the crime occurred.
Types of Signs to Look For
Aside from footprints or impressions, other signs include:
Soil depressions
Kicked over rocks
Clothing fibers
Changes in vegetation
Changes in ambient noise (or lack thereof)
Trackers should identify the subject they are tracking and ensure personal safety by:
Not tracking alone, always carrying a cell phone or radio.
Acknowledging that criminals will hide signs or take countermeasures (e.g., wrapping shoes in cloth).
Analysis of Footprints
Footprints indicate key details about the person being followed:
Size of the footprint:
Larger and wider footprints may indicate male.
Smaller and narrower footprints may indicate female.
Number of footprints helps determine the number of individuals present.
Sole patterns give clues about the type of shoe (work boot, running shoe, etc.).
Depth of footprints informs about the weight of an individual or if they are carrying something heavy.
Factors affecting depth include:
Surface type (soft surfaces lead to deeper impressions).
Angle or dig of the impression indicates directionality:
Toe digs (half-moon shapes) suggest running.
Heel digs indicate backward movement.
Terrain significantly affects the clarity of footprints:
Soft terrains like sand can produce clear prints; harder packed terrains may not.
Disturbances and Environmental Indicators
When clear prints are absent, search for:
Scrapes on soil
Kicked rocks (darker areas expose underlying material).
Disturbed vegetation (broken branches, stomped plants).
Clothing fibers possibly stuck to vegetation or fences.
Inspect vegetation at angles during early mornings to find disturbed dew, which indicates disturbances from movement.
Recent rain can cause sign disturbances to appear more pronounced due to color changes in soil.
Fresh prints in moist soil usually do not shine as bright as surrounding soil.
Observing animal behavior in relation to human presence aids in tracking:
E.g., if grazing animals have moved, it may indicate recent human activity.
Interpreting Clarity and Freshness of Prints
The sharpness of prints can indicate recency:
Sharp, detailed prints are typically fresh (laid down within an hour).
Blurred or obscured prints may signal age.
Environmental factors influencing print appearance include:
Humidity
Time of day
Soil type
Weather exposure (rain, wind).
Further Tracking Indicators
Tracking requires attention to various environmental signifiers:
Trails and runs:
Trails: Highway-like routes between feeding, bedding, and water sources.
May contain multiple tracks and compressed vegetation.
Runs: Routes used by fewer animals, often singular species only.
Bedding areas:
Indicators of resting spots, whether used frequently or only once.
Observed through depressions in vegetation.
Established beds may indicate habitual use for safety from predators.
Transit beds: Used occasionally; recognized by crushed vegetation.
Leis: Rarely used but serve immediate resting or chewing needs.
Dens:
Typically utilized for rearing young (e.g., fox dens).
Feeding areas:
Species-specific, often seasonal, yielding localized runs from feeding activity.
Evidence includes:
Clean cuts on vegetation (indicating rodent activity).
Small serrations suggest deer interaction.
Gnaw marks on nuts from squirrels or beavers.
Signs of Animal Interaction
Rubs and scratches:
Commonly found where animals scratch or mark territory against objects.
Notable among deer bucks for muscle development and dominance display.
Hair and feathers are harder to spot but can be observed in specific lighting.
Commonly found around rubs or kill sites (notable clumps).
Measurement Techniques for Tracks
Measuring animal tracks can be done through various methods:
Measurements can include:
Distance between tracks
Toe-to-toe measurements
Other specific measurements:
Length and width of the track (widest part).
Stride length: distance between the heel of one foot to the heel of another.
Straddle: distance between lines of travel of left and right heels.
Overall pitch: angle of the foot relative to the line of travel.
Acknowledged variations in methods; no single method is superior to another. Measurements greatly inform tracking efforts.