Camelidae and Cervidae Spitting Behavior – NAVLE Study Guide

Overview and Clinical Importance

Spitting behavior is a distinctive and clinically significant defensive and communicative mechanism observed primarily in Camelidae (llamas, alpacas, guanacos, vicunas, and camels). Understanding this behavior is essential for veterinarians working with these species, particularly for safe handling, accurate behavioral assessment, and distinguishing normal from pathological aggression. While Cervidae (deer, elk, moose) do not exhibit true spitting behavior, they employ alternative communication methods including scent marking, licking branches, and saliva deposition that are important for disease transmission considerations, particularly chronic wasting disease (CWD).

For the NAVLE examination, understanding camelid spitting is crucial for questions involving restraint techniques, behavioral assessment, aberrant behavior syndrome (Berserk Llama Syndrome), and zoonotic disease considerations. This behavior represents a unique evolutionary adaptation among pseudoruminants and has direct implications for veterinary practice safety.

Camelidae: Taxonomy and Basic Biology

The family Camelidae consists of six species divided into Old World Camelids (OWCs) and New World Camelids (NWCs), also called South American Camelids (SACs). All camelids are capable of spitting, though the frequency and triggers vary between species.

Camelid Species Classification

Gastrointestinal Anatomy Relevant to Spitting

Camelids are pseudoruminants (also called modified ruminants), possessing a three-compartment stomach rather than the four-compartment system of true ruminants. This anatomy directly enables their spitting ability.

Mechanism of Spitting Behavior

Physiological Process

The spitting process involves voluntary regurgitation of forestomach contents followed by forceful expulsion through the mouth. The behavioral sequence begins with the ears laid back against the neck, accompanied by a gulping or gurgling sound from the throat region. A bolus of food is then regurgitated from C1 (the first compartment) via reverse esophageal peristalsis.

Types of Camelid Spit

Sour Mouth Phenomenon

Sour mouth is the aftermath of green spitting, characterized by a loose-hanging lower lip, gaping mouth, and drooling of green material. This occurs because the acidic stomach contents cause temporary numbing of the lips and oral mucosa. The unpleasant taste and sensation serve as a natural deterrent to excessive spitting.

Clinical significance of sour mouth: Animals with sour mouth may have difficulty eating for 10-15 minutes post-spitting. Feed contaminated with spit will often be rejected by other herd members. This self-limiting mechanism explains why spitting is typically reserved as a last resort.

Triggers and Functions of Spitting

Normal Behavioral Contexts

Warning Signs and Body Language

Camelids provide escalating warning signals before spitting. Recognizing these cues is essential for veterinary professionals to avoid being spat upon and to assess animal welfare.

Escalation Sequence of Warning Signs

Memory Aid - "SPIT" Warning Signs:

• Slackening jaw and lips
• Pinned ears flat against neck
• Increased vocalizations (grumbling, gurgling)
• Tilted nose/head pointed upward

Berserk Llama Syndrome (Aberrant Behavior Syndrome)

Berserk Llama Syndrome (BLS), also called Aberrant Behavior Syndrome (ABS) or Berserk Male Syndrome, is a serious behavioral disorder in camelids characterized by dangerously aggressive behavior toward humans. Understanding this condition is critical for NAVLE examination and clinical practice.

Etiology and Risk Factors

Clinical Signs of BLS

• Aggressive behaviors directed toward humans: spitting, chest-ramming, charging, biting, leg-wrestling
• Sneak attacks: approaching handlers from behind and attacking without warning
• Lack of normal fear response: no hesitation or avoidance around humans
• Sexual behaviors toward humans: mounting attempts, orgling (mating vocalization)
• Territorial aggression: treating human handlers as rival herd members

Prevention and Treatment

Veterinary Handling and Restraint

Spitting Prevention During Procedures

Cervidae: Communication Behaviors

Cervidae (deer, elk, moose, caribou/reindeer) do NOT exhibit true spitting behavior like camelids. However, understanding their oral and salivary communication behaviors is important for veterinary practice, particularly regarding disease transmission.

Salivary Communication Methods

Chronic Wasting Disease (CWD) Transmission

Chronic Wasting Disease (CWD) is a fatal prion disease affecting cervids. CWD prions are shed through saliva, feces, urine, and blood. The scraping and licking behaviors described above are significant transmission pathways.

• Scrape sites: Environmental reservoirs where prions persist in soil and on branches for years
• Indirect transmission: Deer contact contaminated sites days to weeks after infected deer visited
• Social network analysis: Research shows scrapes create indirect contact patterns between deer that never meet directly

Camelidae vs Cervidae: Behavioral Comparison