Castor canadensis Kuhl, 1820

Species diagnosis

General characteristics

• External auditory meatus is connected to the bulla by a long bony tube, which projects downward and outward from the bulla
  
• Jugal broad and strong
• Very large rodent
  • basal length of skull often more than 100mm
  • weight often greater than 30kg
• Hind feet fully webbed
• Claw on second digit on hind foot split
• Tail flattened from top to bottom and scaly

Alaska subspecies