Reptiles

Reptiles

1. WATER LOSS

   • STRATS TO AVOID
     • Ectothermic
       • Lower MR
         • than birds + mammals.  Less water lost via breathing 
       • Nocturnal
     • Skin = impermeable
       • Increase lipids
     • Relatively small
       • Fossorial
         •  - escape harsh conditions
     • Dehydration tolerant
       • Loss of 50% in some Geckos 
       • Extra Renal Excretory Gland
         • Kidney can not deal with excess salt or produce hypertonic urine.     
         • Nasal Salt Gland
           • Storage urates.  Secretes a fluid rich in potassium and sodium   Chamaeleo namaquensis
           • Not seen in Mammals
     • Re-Absorbtion
       • Via Cloaca
   • Aridity
   • Main route Via body surface
     • TEWL - Transepidermal evaporative WL
   • Excretory
     • Faeces and urine (mixed together)
     • Selective
       • Appropriate foods and favourable niches. Avoid high salt food 
     • Uricotelic
       • Produce Uric Acid witch is filtered by the salt glad. - not in mammals 
       • Uric Acid
   • Secretion
     • Milks or TOXINS 
     • Toxins in snakes

2. WATER GAIN

   • Opportunistic drinkers
     • Diet
       • Starvation tolerant
   • Metabolic water
   • Water Storage
     • Aestivation
       • Tortoise - Excrete uric acid after AESTIVATION 
   • ADSORBTION
     • Thorny Devil
       • Moloch horridus  Thin capillary tracts run in parallel to the back of the animal, sucking up water to the mouth. 

3. Thermoregulation

   • Sun basking
   • Avoid Extremes
     • Lizards

4. Successful Taxa