Marine Mammal Gastroenterology

Question 1

Describe the shape of the cetacean stomach.

Where are foreign bodies most commonly found?

Describe the shape of the liver of cetaceans?

Do cetaceans have a gallbladder?

Which cetaceans have a cecum?

Answer 1

• Gastrointestinal
  
  • Cetacean stomachs – three compartments
    
    • forestomach (enlargement of esophagus, receiving chamber)
    • second (glandular compartment – secretes digestive enzymes and HCl;
      
      • margo plicatus separates it from forestomach)
    • U shaped third compartment
    • Strong pyloric sphincter present
    • Gastric foreign bodies most commonly found in forestomach (Puid-Lozano 2018 Environmental Pollution)
  • Liver: bilobed; NO GALLBLADDER
  • Cecum: present in some mysticetes, absent in most cetaceans

Question 2

Describe the GI tract of sirenians.

What is the shape of the liver?

What is their cecum like?

Answer 2

• Gastrointestinal
  
  • Liver: bilobed
  • Cecum: large, has two blind pouches called cecal horns
  • Herbivores + hindgut fermenter; stomach single-chambered
  • GIT 20% of weight