Reptile Biology, Anatomy, & Husbandry Flashcards
What are the 4 divisions of reptilia?
- Testudines (Chelonians) - turtles
- Squamata - lizards, snakes
- Crocodilia - crocodiles, alligators
- Rhynochocephalia - unique lizard species
(Reptilia is the largest and oldest group of vertebrates)
What are 4 causes of variable metabolic rates in reptiles?
- ambient temperature
- diet
- size
- species
(overall SLOW)
What does the lower aerobic capacity of reptiles cause?
switching rapidly to anaerobic metabolism causes quick drainage of energy reserves —> easily fatigued and cannot withstand long-term activity
How do reptiles thermoregulate? How are they able to increase and decrease their internal temperatures?
ectothermic - derive heat from the environment
- INCREASE = basking, color change, cardiovascular shunting, coiling
- DECREASE = seek shade, soak in water, gular fluttering, panting
What is the difference between heliothermic and thigmothermic?
gaining heat from the sun
deriving warmth from objects in its environment
What are the major pro and con to ectothermy?
PRO = don’t need huge food sources for energy
CON = activity depends on temperature
What is the preferred optimal temperature zone?
range of temperature reptiles require to be able to thermoregulate —> varies across all species
- out of zone = disease
- should allow a gradient enclosures so pet can warm up AND cool down
What are the 2 parts of turtle shells?
- carapace = top, dome-shaped
- plastron = bottom, flat; males’ are concave to facilitate mating
What makes up a turtle’s shell? What is it covered by?
dermal bone
keratinized epidermal scales = scutes (innervated and vascularized!)
How are the scutes of turtles named?
- outermost = marginal
- at the neck = nuchal
- midline = vertebral
- between M and O = costal
How does the external anatomy of terrestrial, aquatic, and marine chelonians differ?
higher carapace with short legs
shorter carapace with webbed toes
elongated limbs for swimming
What sexual dimorphism is common in lizards?
males tend to have longer casts/veils
What are the 2 major functions of lizard tails?
- prehensile
- adipose storage
some species can drop for defense!
What are 2 common adaptations of lizard distal limbs?
- adhesive lamella - common in geckos that walk vertically to climb smooth surfaces
- zygodactyl - climbing, traversing uneven terrain (chameleons!)
What scale is found on the abdomen of snakes?
gastropeges - single scale spans the entire ventrum and aids in locomotion
What is the integument of reptiles like? What 3 adaptations can be found within it?
heavily keratinized scales (epithelium)
- glands - scent glands found on inner thigh, salt glands near nares, musk gland at cloaca
- chromatophores - camouflage, temperament (chameleons)
- osteoderms - bony plates
What is ecdysis?
shedding of old layers of scales when lymph separates it from the newly growing layers and activates enzymes
What controls ecdysis? How does it compare in snakes?
thyroid hormones
snakes shed scales all at once, while other reptiles tend to do little by little
What is a spectacle/speculum? In what species is it seen?
epithelial covering over the eye that becomes opaque upon ecdysis
How has the skull of snakes adapted?
- lack mandibular symphysis
- quadrate bone and palatomaxillary arch are looser
allows to have a small mouth able to eat large prey —> able walks food into esophagus, yawning pushes further
What are vestigial spurs?
external protrusions found around the cloaca of primitive snakes (boas, pythons) —> remnants of femur
How does the heart of chelonians, snakes, lizards, and crocodilia compare?
C, S, L = 3 chambers, 2 atria + 1 ventricle
CR = 4 chambers with foramen between R and L aorta
What is unique about the cardiovascular system of reptiles? What advantage does this have?
cardiac shunt (R to L)
during periods of oxygen starvation, blood is able to bypass the lungs (pulmonary artery constricts) and perfuse vital organs —> snake swallowing, turtle diving
- pneumonia = increased lung resistance, blood not reaching where it needs to be
What landmark must be avoided when performing celiotomies on reptiles?
ventral abdominal vein rund directly on midline and forks caudally
celiotomy approach is slightly off midline
How are injections of medications given to reptiles? Why?
must AVOID injecting any drugs in the caudal portion of the body
renal portal system sends blood from hindlimbs and tail directly to kidneys, liver, or heart before reaching systemic circulation (allows for nephrotoxic drugs to go directly to kidneys without being metabolized)
Reptile blood cells:
How does the lymphatic systems of reptiles compare to other animals?
better developed lymphatic system compared to venous system —> lack lymph nodes, but have a vast plexiform lymphatic network
- lymph contamination common in blood draws, especially in turtles!
What are the 4 functions of the reptile respiratory system?
- gas exchange
- vocalization
- buoyancy
- display
How do reptiles prefer to breathe? Where is the glottis found?
through nares with paired paramedian clefts in palate (issues with shedding can cause open mouth breathing)
behind the tongue
How is the lower airway of Chelonians and Crocodilia unique? What is the lung parenchyma of reptiles like?
complete tracheal rings
simple, sac-like, with honeycomb network of faveoli (where gas exchange occurs) +/- aquatic species may be able to exchange gas through their integument
What are 2 reasons that reptiles typically easily develop respiratory disease?
- most species lack a diaphragm = no ability to cough
- primitive bronchociliar transport system
will seek cool temperatures to conserve oxygen
What controls reptile respiration? How should reptiles be stimulated to breath?
low blood oxygen —> increased temp/CO2 = increased tidal volume; decreased O2 = increased RR
DON’T place in oxygen tank, they will not be stimulated to breath —> provide heat (incubator, light source)
Where are the lungs of Chelonians found? How do they breathe?
fused to the underside of the carapace and separated from ventral cavity by a thin non-muscular post-pulmonary septum —> chest does NOT expand
powerful trunk muscles attached to post-pulmonary septum
(VERY tolerant of hypoxia and can convert to anaerobic metabolism)
What are the lungs of primitive snakes and lizards like? Glottis?
- snakes = 2 lungs, right longer than left
- lizards = caudal one third is non-respiratory and function as an air sac
very mobile, right at base of tongue
How does the dentition of Chelonians and snakes compare?
CHELONIANS - lack teeth
SNAKES - 6 rows of teeth (4 upper, 2 lower) that curve backwards to prevent prey from escaping
How is the dentition of venomous snakes different?
modified maxillary teeth (fangs) —> bite and chew to express venom
How does the herbivorous digestive system compare to carnivores? Do reptiles have gallbladders?
prominent cecum
usually —> biliverdin is main bile pigment
What is commonly seen in the caudal coelon or tail of reptiles?
fat pads
Why should anorexic reptiles especially not be force fed?
temperature dysregulation due to diseased state can cause food to sit in static GIT and putrefy
Where are the kidneys of reptiles found? How do they differ in Chelonians/lizards and snakes?
dorsocaudal coelon (nephromegaly = constipation!)
- C/L = symmetrical
- S = right cranial
What to reptile kidneys lack?
- loop of Henle = isosthenuric urine
- renal pelvis and pyramids
What species of reptiles can contain urinary bladders? How do species lacking it void urine?
Chelonians and some lizards
displace urine into colon, where water is absorbed
How do the different species of reptiles excrete urine?
- AQUATIC = ammonia, urea, uric acid
- TERRESTRIAL = uric acid
What disease process does dehydration commonly cause?
kidney damage —> uric acid buildup —> GOUT
What is the normal genitalia of male reptiles like? How is it unique in lizards, snakes, chelonians, and crocodiles?
paired testicles
- L/S = 2 extra-cloacal hemipenes just caudal to the cloaca, snakes also have sexual portion of kidneys
- CH/CR = single intra-cloacal phallus
What kinds of organs are the reptile hemipenes and phallus?
PURELY reproductive —> can be amputated
What is the normal female reptile reproductive system like?
- 2 ovaries
- no true uterus
- eggs develop in oviduct
What are the 3 major reproductive strategies of female reptiles?
- oviparous - lay eggs
- ovoviviparous - produce eggs that hatch internally, birth live young
- viviparous - live young (vipers)
What are the 3 portions of the reptile cloaca?
- coprodeum - GI empties
- urodeum - urinary, reproductive tracts empty
- proctodeum - common opening
What is the goal of proper reptile housing?
mimic natural habitat of the species
- arboreal species = vertical space
- terrestrial species = horizontal space
- heat and humidity to maintain POTZ
What lighting should be provided for reptiles? What is required for vitamin D3 synthesis?
light and heat gradients —> bright AND shade
UV light and heat —> decreased = metabolic bone disease
Why is the type of UV lamp important to understand?
not all are the same —> differenct distances, dispersal, and intensities
What reptiles are herbivores, omnivores, and carnivores?
- HERBIVORES = lizards, chelonians
- OMNIVORES = lizards, chelonians
- CARNIVORES = lizards, chelonians, ALL snakes
BEARDED DRAGONS —> juvenile = carnivorous, adult = omnivorous and if improperly transitioned, obesity and hepatic lipidosis is common
What supplementation is important for proper reptile nutrition? What is the preferred method of feeding?
calcium, minerals, vitamins
gut load insects - insects can groom dust off themselves
What is key to proper reptile nutrition?
VARIETY —> different types of insects, veggies, and fruits
What is an important aspect to welfare of reptiles in captivity?
enrichment
- pegboard allows snakes to climb and totally stretch out
- outdoors = natural UV light!
