Lecture 2

Question 1

Over the past 60 million years, marine mammals have evolved and adapted physiologically and anatomically to do what?

Answer 1

Allowed them to spend all or some part of their lives in water

Question 2

List and give examples(if any) for special adaptions

6

Answer 2

1. locomotion (swimming, buoyancy)
2. Skin (type and colour) ie: polar bears
3. Sensory (smell/hearing)
4. Respiration (dives)
5. Cardiovascular (dives)
6. Movement (propulsion; flippers, tail, webbed feet)

Question 3

Describe how body planes are located?

Answer 3

Body is divided into planes with the body of ht e animal/human on feet/hands facing away

Question 4

Identify the 4 planes

Answer 4

Anterior (front part = head)
Dorsal (back part)
Posterior (back end = butt)
Ventral (abdomens = stomach)

Question 5

In cetaceans, how are appendages named and what are they?

Answer 5

Fins are forearms (b.c they no longer have hind limbs)
They can either be pectoral finds (equivalent to arms located on the side of the chest) or dorsal fins (presented on the dorsal plane (back) and roughly in the middle) OR caudal fins (located n the posterior plane or area)

Question 6

What are flippers?

Answer 6

Flippers are appendages or limbs of Pinnipedia; again similar to cetaceans they are named according to where they are situated in the body.
Ie: pectoral flippers = fore limbs; pelvic flippers = hind limbs

Question 7

List the characteristics of Cetaceans (8)

Answer 7

1) have nostrils (blow holes) on dorsal side of the head
2) large breathing capacity
3) have blubber for thermoregulation and food
4) cardiovascular adapted (thermoregulation and divine)
5) body size is proportional to buoyancy
6) propulsion
7) stability (dorsal fin)
8) echolocation (hunting)

Question 8

List the characteristics of Pinnipeds (7)

Answer 8

1) more amphibious (less extreme aquatic adaptions than cetaceans)
2) propulsion (hind legs/flippers)
3) dense fur
4) Nostrils
5) Dentition (carnivorous)
6) sensory (vision, touch)
7) more varied diving capabilities

Question 9

List characteristics for Sirenians (5)

Answer 9

1) share similar body shape with cetaceans
2) paired nostrils (reduces gas exchange)
3) dense bones (buoyancy)
4) flexible lip with bristles
5) dentition (plants)

Question 10

List characteristics of Polar bears (5)

Answer 10

1) covered in fur (reduce heat loss)
2) skin coloration is black (absorbs heat)
3) Thick layer of FAT (fasting and buoyancy)
4) streamlined head and body (swimming)
5) forepaws (swimming)

Question 11

List characteristics of sea/marine otters (5)

Answer 11

1. Flexible bodies and long tails (allows for both movement on land and water)
2. Has higher metabolic rate (eats large amounts of food compared to body weight)
3. Densest fur: 164, 662 hairs/cm2 (thermoregulation)
4. Has FAT
5. Vision (hitting, sighting enemies above and below water)

Question 12

List characteristics of Humpback whale and what suborder are they in?

Answer 12

suborder: Mysteceti
- found in all oceans
- extremely long pectoral fins (1/3rd of body length); small dorsal fin
- caudal fin with flukes (serrated or jagged) with distinctive underside patterns (birthmark)
- Colour: black on dorsal surface; white/black/mottled on ventral surface)
- Ventral pleats (folds) –> for baleen expansions
- bubble netting
- blow hole: 2 centre; not separate (parallel system)

Question 13

List characteristics of Killer whales and which suborder do they belong to?

Answer 13

Suborder: Odontoceti

• blow hole: single centre
• 2nd most widely distributed mammal around the world
• Found in all oceans and seas
• max body length: 9 m
• weight: 5600 kg
• pectoral fins: M»F
• caudal fins with flukes (males are usually curled)
• dorsal fins erect (males = 1.8 m)
• colouration: back on dorsal, white on ventral, white patch above and behind eye, saddle patch (grey area on base of dorsal fin)
• only cetacean that routinely feeds n other marine mammals and also feeds on fish, sea turtles, etc)
• 2 distinct populations along eastern pacific coast: resident group (eats salmon) and transient group (eats marine mammals)
• in Argentina they eat seals; they would strand themselves on the beaches to grasp the seal and slide back to the ocean

Question 14

List characteristics of Sperm whale and what suborder do they belong to?

Answer 14

Suborder: Odontoceti

• blow hole: off centre single; S-shaped
• largest existing species of toothed whales (19m; 57,000kg)
• found in all oceans
• longest diving. (138 mins) and deepest diver (3000m)
• the head is 1/3 or 1/4th of the length
• spermaceti organ: creates and focuses sounds (clicks)
• largest brain of any animal (7.8 kg)
• jaw: 20-26 comically shaped teeth on each side of its LOWER jaw only! But not used for feeding. Upper jay = vestigial and rarely erupted teeth
• colour: dark grey with white area on ventral surface or lining of the mouth may be white
• pectoral fins: paddle shaped and small
• flukes: flat and triangular
• dorsal fin: thick, low and often rounded
• spermaceti oil is in the head which is different than oils of other melon of the Odontocetis

Question 15

List characteristics of Beluga/Narwhal and which suborder do they belong to?

Answer 15

Suborder: Odontoceti –> technically monodontae (one toothed whales)

• 2 living species of ht is family
• live primarily in the arctic regions of ht e northern hemi
• med. sized whales (5m; 1600 kg)
• Pectoral fins: broad
• Caudal fin: ornately shaped fluke
• lack dorsal fin but they have a ridge used to break ice
• young are black/grey –> adults: white
• very flexible necks (Cervical vertebrae are NOT fused)
• melon heads (trill, squeak and make noises) -_> “Canaanites of the seas”
• Blow hole: single and centre

Question 16

What are the characteristics of dolphins and which suborder do they belong to?

Answer 16

Suborder: Odontoceti

• highest number of species (34-36)
• obvious variations is the development of a rostrum (beak) and body colouration: common dolphin (darker dorsal and lighter ventral), commerson’s dolphin (basic black and grey + white) and killer whale bold black + white)
• may include many patterns (stripes, cape,s overlays, spots, blazes)
• dorsal fin: pointed or falcated (sicked shaped)
• caudal fin has a fluke: 2 symmetrical or equal areas (NO bones; CT +interwoven fibres only)
• adaptability depends on feeding behaviour

Question 17

Describe the characteristics of a pacific white sided dolphin

Answer 17

• found: northern pacific ocean
• max: length = 2.5m; Weight=200kg
• colouration: striking stripes of black, grey, and white n the dorsal area; ventral area = white
• beak is discernible (not visible)
• dorsal fin is large
• opportunistic feeders depending on their habitat (BC eat schooling fish; California = Cephalopoda (squids)

Question 18

What is the general body shape for marine mammals?

What is the exception to his and why?

Answer 18

Most marine mammals are long and slandered to short and tubular.
An exception is polar bears

Question 19

Describe the appendages for the following:

1) cetaceans
2) sirenians
3) seals/walrus
4) otters/polar bears

Answer 19

1) fins
2) flippers + caudal fin with broad fluke
3) Flippers
4) paws (feet)

Question 20

What species of marine mammal is the largest? What is its length?
What is unique about it?

Answer 20

Blue whale is the largest species ever (33m)

Question 21

What young species of whale is smallest? What is its size?

Answer 21

newborn Vaquita (1m)

Question 22

Describe the largest to smallest amoungst dolphins?

Answer 22

Killer whale (9m) –> Spinner Dolphin (1.5m)

Question 23

Describe the largest to smallest amongst seals (give name and length)

Answer 23

Elephant seal (5m) –> Baikal Seal (1m)

Question 24

What is also unique in marine mammals regarding body mass?

Answer 24

Marine mammals have the Largest range for body mass and body size.

Question 25

What species of whale is heaviest (give name and weight)

Answer 25

Blue whales = 220 tons

Question 26

What species of whales is the lightest? (Give name and weight)

Answer 26

Minke whale = 6 tons

Question 27

What species of seal weigh the most? (Give name and weight)

Answer 27

Elephant seals = 3200 kg

Question 28

What species of seal weighs the least (give name and weight)

Answer 28

Baikal seal = 45 kg

Question 29

Describe the basic colour patterns that Marin's mammals have and give examples? (3)

Answer 29

1. Uniform: mostly one colour (ie: polar bears, belugas, sea otters, manatees) 2. spotted or striped : spotted pattern all over body or a distinct pattern may be along head, side, belly or flukes (Ie: seals; killer whales) 3. Saddled or counter shading: dark on dorsal side and light on ventral side (ie: dolphins, whales)

Question 30

Describe the effect age can have on colouration and give examples

Answer 30

Colour can change as they age. Ex: Walrus young harken as they get older, Beluga whales get whiter as they get older Harp seals: newborns (white) --> adolescents (spotted) --> adults (pattern)

Question 31

Describe whether sex can affect colouration and how (give examples.)

Answer 31

Sex can have an affect on colouration. | Examples: seals --> males are darker than females

Question 32

Describe at least 4 ways the differing colour patterns are useful for survival and give examples .

Answer 32

1. To blend into their habitats (seals) 2. to hunt for food (killer whales/polar bears) 3. For protection from enemies (otters/whales) 4. For communication while swimming in groups (dolphins) or differentiate between sexes (seals)

Question 33

Dolphin vs. Porpoises | - describe the basic elements of the colour strips vs. Basic colour with overlay

Answer 33

Head (birdle): consists of blow hole stripes (from BH --> base of the melon) and eye stripe (eye --> base of the melon) eye: surrounded by a round spot (may) + stripe (eye --> anus) Ear: may be stripe--> body Flipper stripe: base of pectoral fins --> eye/mouth or Rostrum Various stripes In dolphins: basic colour with various overly -_> complex patterns of colour

Question 34

Pinniped Colouration | - have differing colours depending on ....

Answer 34

- between wet and dry - between sexes - between ages (soft fur (lanugo) --> no fur) - physiological changes (constriction of BV in epidermis)

Question 35

What is the integumentary system? How many layers are there? What tissues are contained in this system? (Describe what cetaceans and sirenians do not have)

Answer 35

there are 3 skin layers in marine mammals (like humans) Various tissues such as hair, glands and vibrissae (whiskers), paws and claws Cetaceans: no sweat or sebaceous glands. No hair except for bristles like hairs around the mouth Sirenians: no skin glands and have sparse hair on their dorsal surface

Question 36

Describe the specific characteristics of each of the layers of the integumentary system their function and identify marine species specific uniqueness relative to each layer

Answer 36

1) epidermis (outer layer): multilayered (3-5) as in land mammals - consists of flat, solid keratinized cells - generally used for protection against abrasion - contains pigmented (colour) cells used for colouration * *it is renewed every 2 hours (12 times a day) or 9 times faster than humans - in pinnipeds these keratinized cells are lubricated by sebaceous (oily) glands which forms a waterproof pliable layer 2) Dermis (middle layer): contains hair follicles, sebaceous glands (secretes oily substances to lubricate hairs), sweat glands, and claws (Pinnipeds/Sea otters/ polar bears) - well vascularized and contain fat cells 3) Hypodermis (deep layer): blubber composed of fat cells and collagen - acts as insulation and streamlining of body to aid in swimming - walrus, phocids, cetaceans, and sirenians

Question 37

Which species has the thickest blubber of all marine mammals? Thinnest? NONE?

Answer 37

``` Thickest = blue whale (50cm) Thinnest = sirenians None = sea otters and polar bears (have fat instead) ```