Marine Mammal Exam 2

Apnea

Breath holding

Ischemia

Reduced blood flow to certain tissues/organs via peripheral vasoconstriction

Bradycardia

Slow heart rate (less than 60 bpm)

Hypertension

Increased pressure within the arterial system

Vasoconstriction

Reduces blood flow and heat transfer by decreasing the diameter of superficial blood vessels.

Myoglobin

Iron- and oxygen-binding protein found in the muscle tissue of mammals

Hemoglobin

iron-containing oxygen transport protein in red blood cells of all vertebrates

Supersaturation

Higher concentration on one side

Spermaceti organ

Large organ in the forehead of sperm whales that is filled with a fine-quality liquid or waxy spermaceti oil

Decompression sickness

Gas emboli in tissue causing major damage (severe ashima)

Myopia

Leading to focusing well in front of the retina nearsightedness

Tapetum leucidum

-In choroid layer
- Reflecting layer of collagen fibers
- Reflects unabsorbed light back to photoreceptors
- Thicker in pelagic species

Light attenuation

The decrease in light transmittance in relation to depth

Frequency

The number of complete wavelengths that pass a point in a given time

Hertz

Unit of frequency

Wavelength

Horizontal distance between the crests or between the troughs of two adjacent waves

Spectrogram

Illustrate spectral density of sound waves over time

Echolocation

The process of using reflected sound waves to find objects

Phonic lips

Just below the blowhole, allows sound production

Melon

An acoustic fat that transmits sounds from the phonic lips

Aerobic Dive Limit

Period of time when the animal is diving with oxygen

Vocalization

-Air passing through sound producing structures
- Vocal folds or other organ

Non-vocal sound

Produced by some other mechanism (flippers or breaching)

Homodont dentition

All teeth are the same

Heterodont dentition

Different types of teeth

Cavum ventra

Cave like structure in thorat

Gestation

Pregnancy period

-10-17 months
- Correlate with adult body size in odontocetes

Lactation

Duration highly variable among & within species

• Mysticetes: 6-9 months
- Coincides w. peak food availability
- No correlation to calf or mother's body size

• Odontocetes: 8-24 month

Weaning

Changing from drinking milk to real food

Delayed implantation

Blastocysts/embryo maintained in state of dormancy prior to implanting (1-5 months)

• Times birth of offspring to favorable metabolic/environmental conditions

Inter-birth interval

aka "rest"

Years that elapse between calving events.

Body recovers from recent birth before next one

Sexual selection

• Differential reproductive success based on ability to obtain mating partners

• This selective pressure results in sexual dimorphism of:
- Body size
- Secondary structures (weapons/ornaments)
- Mating-associated behaviors

Sexual size dimorphism

When one sex is typically larger than the other

Polygynous

1 male, multiple females
• Selection for large male size (fighting high)

Monogamous

1 mating pair

K selected species

• Long-lived
• Slow growing
• Low reproductive rates/fecundity
• Slow to recover from reductions

Polyandrous

Multiple males, 1 female

• Selection for fighting ability high
• Sperm competition, penis length

Baleen

Thin plates that hang from upper part of a whales mouth

Ram filtration

a.k.a. "skim feeding"
• Swim forward with mouth agape, zooplankton stays in mouth, water filters out through baleen

Capital breeder

Accumulate energy reserves for breeding

Income breeder

Forages and lactates at the same time

Generalist [feeder]

Eats a wide variety of foods

Specialist [feeder]

Eats certain type of food only

Engulfment feeding

Engulfs large amounts of water and filters out prey

Suction feeding

Use tongue as piston to suck prey into mouth
- Floor muscles of mouth distend
- Hyoid depressed
•Origin/attachment of muscles that retract tongue/move head
- Tongue retracts
- Negative pressure forms in oral cavity

Harmful Algal Bloom

When algal species grow in size/bloom they can cause toxic effects on marine mammals

Capable of secreting toxic compounds that can accumulate in the ecosystem

Bioaccumulation

The concentration of chemicals or substances in organisms as they move up the food web

Ecosystem sentinel

A species that responds to ecosystem variability and/or change in a timely and measurable way

• Can indicate an otherwise unobserved change in ecosystem function
- indicates past or ongoing changes in components of ecosystem
- presages future change in the marine environment

Zoonotic disease

Illnesses that can spread between animals and humans

Photogrammetry

Making measurements using aerial photos

Systematic survey

Shipboard or aerial surveys are used to count total number of animals in a given area

Mark recapture

Photo ID, used by wildlife biologists to estimate population size

Capture a portion of the population and mark them (tag or marking)

Release it back into the wild

Population resampled, the second group

Focal follow

Observing (following) a single (focal) animal and recording behavioral states

Animal telemetry

Science of elucidating movement and behavior of animals in relation to their environment or habitat

Keystone species

• Large impact on community structure, may not have high abundance
- Predators (remove dominant species)
- Competitors (remove dominant species)
- Engineers/Facilitators (modify a habitat)
- Foundation species (create a substrate)

• Removing them decreases species richness, evenness, diversity, etc.

Foundation species

Create actual substrate or habitat for other animals to live on (ex. whale falls)

Ecosystem engineer

Species that modify a habitat, especially the physical characters of a habitat

Why do air-filled spaces collapse under pressure?

Prevents gas exchange at depth

What physiological adaptations to marine mammals possess to enable diving?

• Cardiovascular system
• Metabolic rate
• Diving behavior

How are the lungs and systems of oxygen storage different in marine vs terrestrial mammals?

More red blood cells to store oxygen, then muscle, then lungs

How are marine mammal respiratory tracts adapted for lung collapse?

Terminal airways leading to alveoli are reinforced with cartilage/thickened muscle in marine mammals

Describe adaptations to the venous circulatory system

-Stretchy veins

-Sphincter muscle before the heart

-Spleen = blood storage

-Epidural vein (odontocete)
Large blood vessel that brings blood in and around the spinal cord (primary drainage point)

-Extradural vein (pinnipeds)
Runs within the spine

The difference between aerobic and anaerobic cellular respiration

Aerobic- uses oxygen, releases carbon dioxide

Anaerobic- no oxygen present, burn glucose

What is the aerobic dive limit? What physiological changes occur when a marine mammal reaches the ADL during a dive?

Aerobic Dive Limit (ADL)
Period of time when the animal is diving with oxygen

What happens during diving asphyxia? Be able to describe changes to the circulatory system, heart rate, blood flow, & metabolism.

Hypoxia & hypercapnia = asphyxia

decrease in oxygen = hypoxia
C02 increase = hypercpnia

What is the mammalian dive response? What reflexes does it include and how do they work to conserve oxygen?

• Bradycardia
• Peripheral vasoconstriction (ischemia)
• Hypertension

What are the physiological consequences of a long, deep dive (i.e. blood chemistry, rest periods)?

Decompression sickness

Describe how/why nitrogen gas becomes a concern to mammals diving under pressure.

Cannot exchange gas properly, leading to decompression sickness

How have beaked whales been studied in terms of decompression sickness? What are common observations in stranded beaked whales?

Gas emboli (bubbles) in tissues

How does light energy attenuate in the ocean?

Depending on frequency of wavelength

Describe how marine mammal eyes are adapted to see underwater (pigment sensitivity, photon capture, and other pertinent structures)

• Enhanced photon capture
- Spherical lens
- Air/sea visual acuity via cornea anatomy
- Photoreceptor pigment sensitivity
- Reflective tapetum lucidum
- Rapid dark adaptation rates

How do marine mammals eyes focus in air?

Refraction at both the cornea and the lens, leading to focusing well in front of the retina - myopia

Explain how to interpret allometric scaling of brain : body size

Two different equations that allows to predict how large the brain should be to its body size

Explain the role of vibrissae in mechanoreception in various marine mammals

-Used for turbulent tracking
-Allows animal to feel around them

What are the range and speed properties of sound and light waves in air vs. water?

In the air: range = 1,000, speed = 340

In the water: range = 10,000-100,000, speed = 1500

What are spectrograms and what do they illustrate? Understand frequency & intensity of sound waves.

Time series showing loudness

It illustrates the spectral density of sound waves over time.

What 2 types of sound can marine mammals produce?

• Vocalizations (clicks & whistles)- air passing through sound-producing structures- vocal folds or other organ

• Non-vocal sounds (breaching)- produced by some other mechanism

How do mysticetes and odontocetes produce and receive sound?

Vocalization and echolocation

How do pinnipeds produce and receive sounds?

- Larynx
- Tracheal membranes

- Adapted hearing

What is echolocation?

• Production of a high frequency click and waiting to detect a returning echo

• Pulses emitted from special structures in nares

What structures do odontocetes possess that are specific to echolocation?

Melon and acoustic window in jaw

How do sound waves travel during echolocation?

Melon makes a "beam" projecting sounds outwards

Understand the physical parameters of the major zones of the ocean (photic vs aphotic, neritic vs pelagic) and what kind of environmental conditions they present to marine mammals

Neretic zone: area of the ocean that's over the shallow continental shelf

Pelagic zone: deep open water

Photic zone: where light penetrates (vertical)

Aphotic zone: No light (vertical )

What is suction feeding?

Use tongue as piston to suck prey into mouth

What is baleen, what is it comprised of?

Racks of keratin plates that hangs from above

Compare and contrast the stomach morphology of carnivore marmams, cetaceans, and sirenians.

Carnivora:
- Single chambered stomach
- Highly distensible
- Heterodont dentition

Cetaceans:
- Multi-chambered stomach
Forestomach (holding tank)
- Fundic chamber/main stomach
• Manufactures gastric juices for digestion, breaks down most food
- Connecting stomach (sometimes not counted)
- Pyloric stomach

Sirenians:
• Single chambered stomach w/ cardiac gland
• Hindgut fermenters
- Expanded intestinal tract (20m) - Rich in microbes

Describe the types of diets seen among pinnipeds. Cetaceans? Sirenians? Carnivore marmams?

Cetaceans:
• Zooplankton
• Fish
• Cephalopods
• Sharks & rays
• Marine mammals

Sirenians:
• Aquatic vegetation
- Seagrass

Carnivore marmams:
- Fish
- Squids
- Clams & Inverts
- Zooplankton
- Other marine mammals

What is ram filtration?

• a.k.a. "skim feeding"
• Swim forward with mouth agape, zooplankton stays in mouth, water filters out through baleen

What is engulfment/lunge feeding?

-Gulps large amounts of water (70% body weight)
-Ventral throat grooves allows moth cavity to expand
-Uses tongue to push water out and filter through baleen
-Cavum ventral

What is bubble net feeding?

•Cooperative feeding strategy of humpback whales
• Acoustic signals herd & circular net of air bubbles trap fish
• Whales engulf fish as they swim "up the net"

How do odontocetes utilize sound to capture prey?

Echolocation

How can we study or determine what pinnipeds (or other marine mammals) eat?

• Stomach contents & fecal analysis
- Morphology of parts or DNA sequencing

How do we use animal telemetry to study feeding behavior in marine mammals?

TDRs = time, depth recorders
Accelerometers = speed, pitch & roll sensors

Describe the external anatomy of male vs female marine mammals

Pinnipeds:
-External testes (male)
-Genital opening (male)

Sirenians:
External nipple (female)

Cetaceans:
Mammary gland (female)
Mammary slit (female)

What characteristics of most marine mammal populations cause them to increase (in size or #) slowly?

Globally distributed

Differ in reproductive cycle

Describe the seasonal/annual reproductive cycle of pinnipeds, mysticetes, and polar bears.

Pinnipeds:
• Return to land/ice to pup
• Delayed implantation
• Seasonal, synchronized reproductive cycles
• Single offspring
• Postpartum mating

Mysticetes:
-Gestation (10-17 months)
-Birth
-Lactation (6-9 months)

Polar bear (3 year cycle):
• Mating : Spring
- Gestation period
- 6 mo - Delayed implantation 2-3 mo
• Birth: Winter
- Lactation period 1.5-2.5yrs

Provide a hypothesis for why mysticetes undertake annual migrations of large geographic scale.

• Seasonal variation of food sources
• Thermoregulatory benefits
• Predator avoidance

Why do the females of many species synchronize their estrous cycles?

• Dilution effect
- Results in synchronized births, reduce neonatal predation

• Reduction in male harassment
- In species with postpartum estrus

• Allo-maternal care of calves
- Non-mothers provide care & vigilance

How long is the gestation period in cetaceans and pinnipeds?

Pinnipeds: 12-15 months

Cetaceans: 10-17 months

Compare and contrast lactation behavior among seals and sea lions.

Sea lions leaves pups after lactation compared to seals