Lecture 8 (female reproduction) Flashcards
What are the anatomical differences between marine mammal repro systems and terrestrial repro systems?
- thermoregulation of testes
- development of fetus
What caused reproductive behavior and anatomical morphology evolution to occur in marine mammals
WATER
Which species breed ONLY in water?
- Cetaceans
- Sirenians
- Sea Otters
- SOME pinnipeds (odobenidae, Walrus)
Which species breed ONLY on land?
- Polar bears
- SOME Pinnipeds (Elephant seals)
Which species breed IN BOTH ENVIRONMENTS?
- SOME Pinnipeds (Gray seals)
Which species gives birth IN WATER
- Cetaceans
- Sirenians
- Sea Otters
Which species gives birth ON LAND or ICE
- Polar bears
- Pinnipeds
Which species youth are precocious and what does precocious mean?
- Cetaceans
- Sirenians
- Precocious means born with adult like abilities (needing little care or protection)
Which species youth require a lot of parental care?
- Pinnipeds
- Polar bears
- Sea Otters
Which females continually forage for food to feed their young?
- Cetaceans
- Sirenians
- Sea otters
- SOME pinnipeds (Walrus)
What are some advantages and disadvantages of females foraging for food for their youth?
Advantages - maintain energy requirement
Disadvantages - leaving youth alone
Which females fast at early stages of feeding their youth?
- Polar bears
- SOME pinnipeds (Elephant seals)
What are some advantages and disadvantages of females fasting during the early stages?
Advantages - Young not left alone
Disadvantages - females must remain alive while fasting
What are the various gestation ranges?
What can influence gestation in whales?
- Sea otter (6mo)
- Walrus (16mo)
- Odontocetes (7-16 mo) VS mysticetes (10-12 mo)
- Otariids and phocids (11-12 mo)
- Sirenians (manatee 13 mo; dugong 14 mo)
- Polar bear (8 mo)
DIET can affect gestation - Mysticetes can vary (squid-feeders 16mo) > plankton/fish - feeding species (10-13 mo)
Which odontocetes have longer gestation periods and reproductive intervals?
Sperm whale and Killer whale
Which mysticete has a longer gestation period and reproductive intervals and by how how long?
Blue and Grey whales
- By 10% longer
What are the various female reproductive intervals (time between babies)?
- Sea otter; otariids, phocids (1 yr)
- Walrus (2-4 yrs)
- Odontocetes (3-5 yrs)
- Mysticeties (1-3 yrs)
- Manatee (2-4 yrs)
- Dugong (3-7 yrs)
- Polar bear (2-4 yrs)
What are the maturation rates of young cetaceans and sirenians?
- Plankton feeders (4-8 yrs)
- Fish feeders (4-10 yrs)
- Squid feeders (4-10 yrs)
- Manatee (4-8 yrs)
- dugongs (6-12 yrs)
What is the life expectancy in cetaceans and sirenians?
Smaller species - 14-50 yrs
Larger baleen whales, sperm whales, killer whales - 50-100 yrs
Manatee - 60 yrs
Dugong - 70 yrs
What are the basic organs in a marine female’s reproductive tract?
- Ovary
- Oviduct
- Uterus
- Cervix
- Vagina
- Clitoris
- Vaginal vestibule
Where do variations exist in reproductive organs?
- Anatomy
- morphology
- physiology
- hormone cycle
What are the three types of uterus that marine mammals can have?
- Duplex Uterus
- Bipartite Uterus
- Bicornuate Uterus
What are the features of the Bicornuate Uterus and which species has it?
Features
- 2 horns
- single body
- NO septum
- 1 cervix
Species
- Cetaceans
- Sirenians
- Sea otters
- polar bears
What are the features of the Bipartite Uterus and which species has it?
Features
- 2 horns
- separated by a septum
- has 1 cervix
Species
- Phocids (earless)
What are the features of the Duplex Uterus and which species has it?
Features
- 2 separate horns
- 2 cervix
Species
- Walrus
What are the tissues that support the Uterus
- Broad ligaments
Layers - Outside - serous membrane
- Middle - myometrium
- Inner - lining or endometrium
What is the function of the ovaries?
- where eggs mature, released during ovulation
- always 2 functional ovaries
- they are surrounded by ovarian bursa
- suspended from abdominal or pelvic cavity by short mesentery (mesovarium)
What is the mesovarium?
- attached to dorsal side of a large ligament called ‘broad ligament’
- supports ovaries
What is function of the Ovarian Bursa?
- Ensures eggs pass into oviduct (where fertilization occurs); implantation in uterus
Describe the shape and size of the ovaries
Shape and size vary among mammals
- Manatee - flat and broad
- Sea otters - compressed oval
- odontocetes - spherical or ovoid
- mysticetes - flat elongated
- Phocids - ovoid, smooth
Describe the cervix
- Highly muscular sphincter
- Contracts on itself
- Separates the uterus from vagina
Describe the cetacean cervix and what determines this?
- Cetacean cervix is long with a thick wall that extends a lumen into the vagina
- length depends on species
- Short in Narwhals
- Long in Harbor Porpoises
What are mammary glands and where are they located?
- nipples providing milk
- various configurations and locations
What are the differences between the mammary glands in phocids vs otariids
- Phocids - mammary glands under blubber and encased in connective sheath
- Otariids - form into a thin layer under blubber covering most of ventral surface
Where are mammary glands found in cetaceans?
- 2 nipples, one on each side of midline of ventral surface
- during nursing, nipples protrude under contraction
Where are the mammary glands found in sirenians?
- 1 nipple under each pectoral flipper
Where are the mammary glands of sea otters?
- 2 nipples on lower abdomen
Where are the mammary glands of polar bears?
- 4 nipples, 2 on each side of the midline
How many nipples do otarids, odobenids, and some phocids have?
4 nipples
When are the lactation periods for the hooded seal, harp seal, Grey and elephant seals, Ringed seal, and Sirenians, some cetaceans, and walrus. what do they depend on?
SPECIES SPECIFIC
- Hooded seals = 4 days
- Harp seals = 12 days
- Grey and elephant seals = 3 weeks
- Ringed seal = 6 weeks
- Sirenians, some cetaceans, and walrus = 2 YEARS
In large cetaceans what are the lactation periods
Squid feeders = 24 months
Plankton feeding whales = 5-7 months
How does the marine mammal milk composition compare to the human?
Fat = HIGH = (40-50%)
Protein = HIGH = (7-19%)
Carbs = LOW = (0-5%; whales 2%) calculated in lactose
Energy content = high = (10KJ/g)
Kcal/100ml = (443 Kcal) way more
Where do cetaceans and walruses feed their young?
Underwater
Where do sea otters feed their young
Lying on their mother’s stomach or beside her
Where do sirenians feed their young?
though nipples with nostrils slightly in or out of water
