Lecture 5B Flashcards
What is propulsion and how have marine mammals evolved to increase propulsion?
- A force causing movement
- Evolved decrease in length fore and hind limbs
- Increased surface area of fore and hind limbs
What is the body shape of most marine mammals and what is the exception?
- Usually long and slender
- Exception is the polar bear
What helps cetaceans move through water?
- Caudal fins
- Caudal fins divided into two flukes
What helps Pinnipeds move throughout land and water?
- Uses paired fore and hind flippers
What helps Sirenians move throughout water?
- Caudal fin
What helps Sea otters and Polar bears move throughout land and water?
- Hind and fore paws
How do Otariids swim fast?
- pumping pectoral flippers
- flexible skeletal system allows for fast swimming and tight turns
- some instability in trajectory
How do Phocids swim?
- Pelvic oscillations (hind limb swimming)
- lateral motion
- webbed toes creates more thrust
- more stable than otariids but not as fast
- fore flippers are for steering
How do odobenids swim and move?
- Pelvic oscillations (hind limb swimming)
- Hind flippers used for propulsion
- Fore flippers for steering
What do pectoral fins do for cetaceans?
- allow them to move through water more efficiently
- Shape of pectoral fin varied by number and length of phalangeal bones
Describe the pectoral fin of the cetacean
- elbow near their body
- moving part consists almost entirely of what is known as the fore arm and hand
Why are humback whale pectoral fins unique?
- very long and narrow
- adapted to high maneuvering during feeding
- 25-35% of body length
- Large bumps called Tubercles (act as lifting devices)
What are the four layers of the caudal fin?
- Cutaneous layer
- Thin blubber layer
- Ligaments layer
- Inner core (dense fibrous tissue)
- Inner core houses blood vessels producing counter current system
How do cetaceans propel themselves?
- Caudal oscillation
- 2 epaxial muscles contract while 2 hypaxial muscles relax THEN vice versa
- Use of elastic band to power caudal fin
What are the the two epaxial muscles and the two hypaxial muscles?
Epaxial (upstroke)
- Mulifidus extensor
- Longissimus extensor
Hypaxial (downstroke)
- Flexor caudae lateralis
- Flexor caudae medialis
How do Sirenians move themselves? (6 things)
- Flat paddle like front pectoral flippers
- Used for spinning or turning
- Also used for “walking”
Caudal fin - Broad fin allowing for powerful bursts of speed
- Caudal oscillations
- Steering, banking, rolling
How do sea otters propel themselves?
- Pelvic paddling
1. ventral surface up swimming (VSU)
2. Ventral surface down swimming (VSD)
3. Alternating ventral surface up and down swimming (VSUD) (grooming behaviors) - Pelvic undulation (Diving)
- achieved through vertical flexing of the vertebral column
How do polar bears swim?
- Strong forepaws (crawling action)
- Hind limbs trail behind
How does water compare to air?
- 1000x more dense
- 60x more viscous
- 25x faster heat transference
- reduction of light penetration
All or a combination of which systems must adapt for proper diving? (6 things)
- Cardiovascular
- Nervous
- Respiratory
- Excretory
- Sensory
- Reproduction
What factors influence diving behaviors in general? (7 things)
- Environmental water conditions
- Temperature
- Seasons
- Age
- Health
- Size of the animal
- Time spent hunting
When describing what physiologically occurs within a seal or whale during a dive it is important to consider what? (4 things)
- Blood composition
- Cardiovascular responses
- Metabolic consequences
- Adaptations to pressues
What dictates the amount of energy and oxygen required to hunt and acquire food?
Size and Weight
Sea Otter diving behavior (Mustilidae)
- continuously diving
- Dive in shallow water
