Herp Behavioral Disorders

Question 1

Describe the natural behavior of herpetological species.

How do herp species behaviorally thermoregulate?

What behavioral adaptations do amphibians have to conserve water?

What sensory adaptations contribute to behavior?

What defensive behaviors do herps exhibit?

Answer 1

• Reptiles and amphibians differ from mammals and birds in that:
  
  • Metabolic rates are flexible, resting MR are lower than birds and mammals
  • Do not necessarily need food as often
  • Majority of their energy comes from anaerobic metabolism, rapid exhaustion
  • Spend a lot of their time doing nothing, bursts of activity
  • Much of behavior is motivated by regulating temp or moisture
• Ectothermy:
  
  • Behavioral thermoregulation in reptiles and amphibians.
    
    • Amphibians – choose high moisture over warmer temp if not available together.
    • Body temperature relatively stable, no optimal temperature, need gradient.
    • Absence of behavioral thermoregulation may indicate disease or illness.
    • Inability to behaviorally thermoregulate - stress or death.
  • Lower metabolic energetic demand, higher assimilation efficiencies.
    
    • Feed on small, less energetically profitable prey.
    • Limited aerobic energy production, reliance on anaerobic metabolism for high activity.
    • Can require hours to recover from few minutes of strenuous activity.
    • During periods of inactivity, reducing body temp improves metabolic efficiency.
  • Body size
    
    • Reptiles – juveniles exhaust more quickly after short bouts of activity, endurance tends to increase linearly with size.
• Water conservation and osmotic balance:
  
  • Water acquired from food, drinking, chemical production via metabolism.
  • Most reptiles excrete uric acid, able to retain more metabolic water vs those than excrete urea i.e. mammals, terrestrial chelonians, many amphibians, or ammonia i.e. fish, crocodilians, aquatic chelonians, most aquatic amphibians.
  • Water lost through urine, feces, evaporation (#1), salt glands.
  • Many amphibians will concentrate activity around rain events.
    
    • Water conserving postures - body against substrate, limbs pulled in, head tucked, eyes closed.
      
      • Reduces exposed surface area.
      • Amphibians may establish wetting front on dry soil.
        
        • Water accumulates between animal and soil. Prevents movement of water to drier soils, prevents continuous water loss.
      • May burrow deep in sand and soils - underground for months or years.
  • Marine reptiles and many herbivorous or invert eating reptiles and amphibians excrete excess ions.
    
    • Sea snakes, sea turtles, marine iguanas, SW crocodiles must drink FW.
      
      • Excrete salt through glands in eyes, nose, or mouth.
      • Salt glands >> kidneys at excreting excess salt. Requires more energy - active transport.
  • Desert animals harvest dew, rain, sleet, snow off ground, plants, themselves.
    
    • Some spp, dietary and metabolic water is sufficient.
• Sensory adaptations:
  
  • Extra-optic phororeception for sensing light and dark, have color vision.
    
    • Burrowing, cave-dwelling spp have lost vision but still exhibit phototaxis.
    • Color vision important for social communication – mate assessment, locating prey, microhabitat selection, camouflage or social interactions.
  • Hearing
    
    • Anurans – strong reliance on auditory communication – individual recognition, despotic spacing, release and alarm calls.
      
      • Anurans and salamanders – operculum attached to suprascapular, allows hearing of seismic vibrations.
    • Many reptiles also use acoustic communication. Airborne and ground-borne sounds.
      
      • Lower jaw, lateral line systems, tactile abilities of shells.
  • Chemoreception
    
    • Communication, mating, movement, prey location, predator identification and risk assessment. Vomeronasal organs.
    • Plethodontid and Ambystomatid salamanders nose-tapping behaviors, chemical cues picked up via capillary action.
    • Tongue-flicking behaviors to determine directionality when following chemical cues.
• Foraging and predation:
  
  • Most are ambush foraging carnivores.
    
    • Many have projectile tongues for prey capture.
    • For most, prey strikes triggered by prey movements.
    • Herbivorous reptiles use visual and chemical cues.
  • Most swallow prey whole. Many species have specific additional behaviors to lure prey.
• Sleep and other endogenous rhythms:
  
  • EEG data shows sleep present in amphibians, turtles, crocodilians, but do not exhibit rapid-eye movement (REM) or deep sleep.
  • Crocodilians may sleep one hemisphere of the brain at a time.
  • One study in a snake – sleeplike brain waves corresponded with slower breathing and HR.
• Color change:
  
  • Camouflage, thermoregulation, social communication.
    
    • Chameleons and other lizards use their colors primarily for communication, rather than for camouflage.
      
      • Brighter coloration signals dominance.
    • In snakes, color change aids in thermoregulation.
  • In amphibians, largely related to camouflage, plays role in temp regulation and reducing evaporation.
    
    • No evidence that color changing in amphibians is used socially.
• Defense:
  
  • Predatory avoidance and immobility.
    
    • Most rely on immobility and cryptic coloration as primary defense.
    • Behavioral responses to chemical alarm cues include avoiding substrates, increasing use of or delaying emergence, reducing movement rates.
  • When predatory avoidance has failed, will attempt escape.
    
    • i.e. Uromastyx will retreat to rock crevices, wedge themselves and inflate their lungs or tails.
  • Defensive postures and displays
    
    • Inflation, elevating body to appear larger/signal alertness.
    • Expanding frills or hoods around head, generation of noises.
    • Some snakes – nuchal glands on back of neck with toxic compounds.
    • Reptiles may gape their mouths.
    • Amphibians – “unken” reflex.
      
      • Will raise head, limbs, and tail (salamander) dorsally to expose or accentuate their aposematic coloration.
      • Many with or without toxins will contact body with head tucked ventrally to present poison glands.
    • If seized, will struggle, hiss, urinate, defecate, discharge cloacal glands.
    • Vipers perform body bridging – lateral raising of the trunk region, inflation, body flipping/jerking. Not in Colubrid snakes.
    • Many lizards and snakes exhibit death-feigning behavior (thanatosis).
      
      • Hog-nosed snakes (Heterodon) common in wild but wanes in captivity, potentially through habituation.
  • Tail displays and tail autonomy
    
    • Crocodilians and some large lizards (iguanas, uromastyx) will use tails to whip or strike.
    • Most salamanders, lizards, some snakes can automotize their tails.
      
      • Salamanders – weakness in skin and muscle between caudal vertebrae.
      • Reptiles – fracture planes within each caudal vertebra.
      • Ease of tail autotomy can vary with spp and population, sex, and previously unbroken and regenerated tails.
      • Consequence of tail loss: Leopard and fat-tailed geckos – loss of water and fat stored in tails.
  • Counter-attack
    
    • Last resort defense.
    • Venom.
      
      • Cottonmouths (Agkistrodon piscivorous) – aposematic coloration, tail rattles, mouth gaping displays.
      • Spitting cobras (Hemachatus) spray venom.
      • NW salamanders (Ambystoma gracile) – concentration of poison glands along tail, will slap irritating toxins into eyes.
      • Salamanders (Pleurodeles, Salamandrina, Tylototriton) – spear-shaped ribs that can penetrate when animal is seized, injects toxins.
      • Some frogs i.e. Bruno’s casque-headed frogs and Greening’s frogs have bony spines with poisonous skin secretions.

Question 2

Describe the natural social and reproductive behaviors of herpetological species.

What sourt of courtship displays do the various groups use?

Describe copulation in these species.

What is gestation and incubation like in these species?

How much parental care is invested in young herps?

What nonreproductive social behaviors are displayed by herpetelogical species?

Answer 2

• Social and reproductive adaptations:
  
  • Courtship:
    
    • Ritualized male-male combat, visual/vocal displays, chemical communications/pheromones.
    • Male crocodiles – dominance hierarchy.
    • Turtles – visual and chemical cues. Males become brighter in some spp.
    • Lizards and tuataras – territorial defense behaviors.
      
      • Head bobs, arm-waving, push-ups, tail-flagging, dewlap displays.
      • Males secrete chemical signals from femoral pores.
    • Snake – 3 phases: tactile-chase, tactile-alignment, coitus.
      
      • Females indicate receptivity by gaping cloaca.
      • Male snakes may try to maintain upright posture for longer vs others, sign of dominance.
      • Surge of testosterone following combat aids in courting females.
        
        • Spurs may be used in combat.
    • Amphibians – visual, vocal, tactile, chemical cues.
      
      • Male anurans – strong reliance on calls. May also wave limbs.
      • Tactile and chemical signals very important for salamanders.
        
        • Using tail to touch female while delivering pheromone, touching or bumping the males head to females body, or tail straddle walking.
        • Male plethodontids have mental hedonic gland sin the chin, engage in snapping behavior to apply pheromone to the females bloodstream.
      • Female amphibians also engage in courtship and mate assessment.
        
        • Will directly compete with other females for males.
        • Female eastern red-backed salamanders may use quality of prey found in male fecal pellets in mate assessment.
  • Mating:
    
    • Fertilization – internal or external.
    • Male reptiles have intromittent organs to transfer sperm to females.
    • Turtles and crocodilians have a single phallus.
    • Snakes and lizards have two hemipenes.
    • Male tuataras do not have an intromittent organ – sperm transfer by cloacal kissing.
    • All anurans and salamanders have external sperm transfer.
    • Caecilians have phallic structure for internal sperm transfer.
    • Most salamanders have external sperm transfer but internal fertilization.
    • Most anurans have external fertilization.
      
      • Males engage in amplexus, seize female form behind with forearms around axillary, inguinal, or cephalic area.
        
        • Adhesive pores along males arms or enlarged pads on thumbs.
        • External sperm transfer with internal fertilization – deposition of spermatophore.
          
          • Females will pick up sperm packet by tail straddle walking or nudging.
          • Females may store sperm for months or years.
      • Most male reptiles aggressive towards other males and sometimes toward females during mating season.
        
        • Mating behaviors are variable in length of time.
  • Gestation:
    
    • Female reptiles and amphibians generally less active during gestation. Most snakes will not feed.
    • Many female pythons brood eggs for up to 2 months, increase temp of clutch by muscle contractions.
    • Female king cobras build a nest out of sticks and leaves, guard nests for 2-3 months.
    • Turtles and crocodilians also build nests.
    • Live bearing rare among anurans, salamanders.
    • Majority of caecilians retain eggs for some portion of larval development.
    • Some toads and salamanders retain eggs and birth tadpoles or developed froglets.
  • Parental care:
    
    • Found in every major group of reptiles and amphibians.
    • Crocodialians – well-developed parental care.
    • Most chelonians abandon nests after burying.
    • Hatchling crocs and some turtles vocalize from within their eggs to coordinate hatching.
    • Some lizards guard eggs.
    • Pit vipers remain with young for several days after birth.
    • More common in caecilians and salamanders vs anurans.
      
      • External fertilization often associated with male parental care, internal fertilization with females.
      • Parental care usually related to attendance/defense or transport of eggs or tadpoles.
      • Females may consume dead or infected eggs to prevent spread of disease.
      • Gastric and vocal sac brooding in some spp.
      • Some spp, tadpoles climb onto parent’s back for transport, will complete development.
      • Debdrobatidae spp will distribute tadpoles and check on them regularly, will feed unfertilized eggs.
• Nonreproductive social behavior:
  
  • All crocodilians are highly social.
    
    • Hierarchy and males that defend territories, females, and juveniles.
  • Many turtles and tortoises spend time together outside of breeding season.
  • Male lizards territorial in general.
  • Great dessert skinks build and maintain burrow systems with family groups.
  • Snakes generally not social, but rattlesnakes may aggregate.
  • Most amphibians presumed solitary outside of breeding season.
    
    • Will huddle during dry conditions to reduce surface area to volume ratio and evaporative water loss.
    • Salamanders can be highly territorial.
• Behaviors particular to captivity.
  
  • Signs of distress – refusing food, difficulty shedding, weight loss.
  • Edging behaviors – continuous pushing against walls of enclosures.
  • Some species are gregarious for basking and will not bask if housed individually.
  • Some require live prey for feeding stimulus.

Question 3

What is the first part of a thorough behavioral workup in a herp?

What behavioral issues may indicate problems with the environment?

What are some common behavioral issues with feeding? What tcan they indicate?

What are some common behavioral issues with handling?

Answer 3

MARMS – 83. Clinical Behavioral Medicine

Anatomy and Physiology of the brain & behavioral responses

• 3 sections of brain
  
  • Forebrain (telencephalon & diencephalon)
    
    • Smell, taste, rhythms, sensory motor
    • Hypothal, thal, infundibulum, pit gland and pineal
  • Midbrain (mesencephalon)
    
    • Neuroendocrine, visual processing
  • Hindbrain
    
    • Hearing, balance, physiologic homeostasis
• Stress
  
  • Hypothalamus/pituitary/adrenal (HPA) axis
• Approach to behavioral appointments
  
  • History important, photos of enclosure, and behaviors/postures
• Anamnesis, PE, and Behavior
  
  • Most b/c of deficiencies in captive management (environment and diet)
• Clinical Disease
  
  • Husbandry is key
  • Believed that heat receptors are not same as pain receptors in reptiles
  • Prevention: Provide temp gradient (horizontal or vertical)
    
    • Diurnal- helpful to have overhead heaters with appropriate day cycle
    • Nocturnal- under cage heater; although be careful with burrowing species
  • Observation: Shy or stressed species hidden rather than eating
    
    • Likely hiding in cooler area and can lead to immunosuppresion
    • Prevention: Appropriate space and hiding areas; feed in those areas if needed
  • Observation: Rostral abrasions
    
    • Steptypic behaviors related to escape
    • Avoid mirrors, glass, and reflective surfaces
    • Prevention: Place physical barrier- like black tape; one-way glas…ect…
  • Observation: Obstruction due to ingestion of substrate/pica
    
    • Prevention: provide food on tray
  • Observation: Stress related to environment
    
    • Knowledge of arboreal, terrestrial, or aquatic
    • Snakes may scent mark territory & changing caging arrangements may continued stress
    • Snakes may also need to stretch out with abdominal discomfort and enclosure may not be large enough
    • Foraging opportunities
• Behavioral Issues Relating to Feeding
  
  • Observation: Anorexia, inappetance
    
    • Competition from conspecifics
    • Overly restrictive and inappropriate environments
      
      • Constipation & impaction common problem, particularly if humidity is low, and temp is high
      • Color of prey (wild caught snakes may say hell no to white rats)
    • Feeding of live vert prey is illegal in most countries (didn’t know that)
    • Seasonal or hormonal weight loss or inappetence
  • Observation: Inability or unwillingness to drink water
    
    • Moisture in diet
  • Observation: Inactivity and overeating leading to obesity
    
    • Watch out for hepatic lipidosis
  • Social Behavior/Handling
    
    • Sophisticated communication, problem-solving, parental care, and play
    • Few species live in social groups constantly
    • Sexual aggression toward humans by reptiles most commonly reported by Iguana
      
      • Often initiated by the presence of a menstruating woman
    • Green iguana- Femoral gland pore size was positively correlated with freq of head bob displays and plasma level of testosterone during breeding season in males > 12 months
  • Reproductive Behavior: color changes, displays

Whole patient approach: captive environment, handling care, and behavior- NOT focusing on presenting

Question 4

Discuss the behavioral training of reptiles.

What are three primary goals of training reptiles?

What is enrichment?

What are the goals with enrichment?

What are the six components of the AZA SPIDER training acronym?

Answer 4

MARMS – 14. Conditioning and Behavioral Training in Reptiles

Training and enrichment

1. Opportunities for reptiles to display natural behaviors
2. Allow human-animal interaction with keepers
3. Reptiles participate in veterinary medical care

Enrichment:

• AZA Behavior Scientific Advisory Group Definition: “Enrichment is a dynamic process for enhancing animal environments within the context of the animal’s behavioral biology and natural history. Environmental changes are made with the goal of increasing the animal’s behavioral choices and drawing out their species-appropriate behaviors, thus enhancing animal welfare.”
• Goals
  
  • To promote species-appropriate behaviors
  • To provide behavioral opportunities
  • To provide animals with choices or control over their environment
• Use individual and natural history
• Scent enrichment; cinnamon encourages foraging in the komodo dragon
• Feeding during more active times
• Addition or changes to rocks, branches, plants, light, substrate
• Thermoregulation choices
• Different levels
• Nile monitor (Varnus niloticus) pool with cascading water with different levels and variety of foraging food items

Training

• Operant conditioning for husbandry and medical behaviors
• Moving into a crate
• Medical procedures - ultrasound, nail trim, venipuncture, medications
• AZA SPIDER
  
  • Setting goals - specific behaviors to be trained; include all parties (owners/keepers, veterinary staff, reptile)
  • Planning - create a series of steps for shaping behavior; who will be training; when training occurs; equipment or tools needed
  • Implementing - train the behavior over sessions, advance only when animal ready, clear communication about steps and timelines
  • Documenting - create a document that tracks progress and shows trends
  • Evaluating - review documentation and training plan
  • Readjusting - make changes necessary to achieve goals
• Disney’s Animal Programs Website: http://www.animalenrichment.org or http://www.animaltraining.org
• Crating of komodo dragon as well as voluntary procedure participation to avoid sedation/anesthesia
• Shifting crocodilians or venomous snakes into crates, off exhibit, or then into tubes