Lecture 2 Flashcards
study for midterm and final (51 cards)
How long have marine mammals been adapting both physiologically and anatomically?
60 million years
What are some examples of adaptations? (7)
- Locomotion (swimming/buoyancy)
- Skin (type/color)
- Sensory (smell/hearing)
- Respiration
- Cardiovascular
- Movement (propulsion)
- Kidneys (specialized - conserving need for water)
What are the planes that the body is divided up into?
- Anterior (front “head”)
- Dorsal (back “top”)
- Posterior (back end “butt”) (sometimes refered to as caudal)
- Ventral (abdomen “stomach”)
How are fins named where?
Based on body position
(pectoral fins = arms on the side of chest)
(Dorsal fins = if present located on the dorsal plane (back))
(Caudal fins = located on the posterior plane)
List the features of Cetaceans (Whales, Dolphins, Porpoises) (8 things)
- Nostrils (Blow holes) on dorsal side of the head
- Large breath capacity
- Blubber (thermoregulation)
- Cardiovascular adaptations
- body size
- Propulsion
- Stability
- Echolocation
List the features of Pinnipeds (Seals, Sea Lions,, Walrus) (7 things)
- More amphibious (less extreme aquatic adaptations)
- Propulsion (hind legs/flippers)
- Dense fur
- Nostrils
- Dentition (Carnivorous)
- Sensory (vision, touch)
- More Varied diving capabilities
What are the seal fur differences between the earless seal and the eared seal?
Eared Seals have more secondary hairs for warmth than earless seals
List the features of Sirenians (Manatees, Dugongs) (5 things)
- Similar body shape to cetaceans
- Paired nostrils (reduce gas exchange)
- Dense bones (buoyancy)
- Flexible lips with bristles
- Dentition (plant eater)
List of features of Polar Bears (5 things)
- Covered in fur (reduce heat loss)
- Skin coloration is black (absorbs heat)
- Thick layer of fat (fasting and buoyancy)
- Streamlined head and body (swimming)
- Forepaws (swimming)
List of features of Sea/marine otters (4 things)
- Flexible bodies & long tails (allows for movement on land and water)
- Has a high metabolic rate (large food intake compared to body size)
- Densest fur (164,662 hairs/cm2)
- Vision
What is the body shape for MOST marine mammals and what is the exception?
- long and slender to short and tubular
- exception is Polar bear
How do cetacean forelimbs differ from other marine mammals in terms of what we call them?
Cetaceans = fins
Sirenians = flippers + caudal fin
Seals/Walrus = flippers
Otters/Polar Bears = Paws
Which mammals have the largest range in body size?
Whales (from 33m (blue whale) to 1m (newborn Vaquita))
Which marine mammals have the largest range for body mass?
Whales range from 220 tons (Blue Whale) to 6 tons (Minke Whale)
Seals range from 3200 kgs (Elephant Seal) to 45 kgs (Baikal Seal)
What are the 4 base color patterns for marine mammals
- Uniform - mainly one color
- Spotted
- Striped
- Saddled or counter shading
How is the uniform pattern described?
What are the marine mammals that have a uniform color pattern?
- Mainly one color
- Belugas, polar bears, sea otters, manatees
How is striped pattern described?
What are the marine mammals that have a striped pattern?
- Distinct pattern may be along head, side, belly, or flukes
- Pacific white sided dolphin/killer whale
How is the saddled or counter shading pattern described?
Which marine mammals have this pattern?
- Dark on dorsal side and light on ventral side
- Dolphins and whales
What other factors can determine skin color differences
AGE
- Walrus young darken with age
- Beluga young whiten with age
- Harp seals develop pattern over time but are born white
SEX
- Males are darker than females
How are colorations adaptations in marine mammals? Which species belongs to which adaptations?
- Blend into habitat (seals)
- hunting (killer whales, polar bears)
- protection (whales/otters)
- communication (Dolphins - swimming in groups) and (seals - differentiate between sexes)
In Cetaceans what does a bridle consist of?
- a blow hole stripe
- an eye stripe
- flipper stripe
What is a lanugo?
- Fetal pelage (soft fur) usually lost a few days or weeks after birth (in pinnipeds)
What factors determine color in pinnipeds?
- Various colors of hair or pelage
- may change between dry and wet
- between sexes
- physiological changes (constriction/expansion of blood vessels in epidermis)
What external skin features do Cetaceans lack?
- sweat or sebaceous glands
- hair except bristle like hairs around the mouth