1. Marine Mammal Reproductive Structures, Strategies, & Patterns MARE 390 Dr. Turner

2. Testes, One, Two Phocid – testes inguinal Otariids – testes scrotal Walrus – inguinal; scrotal during mating Pinnipeds – bacculum (penis bone) Cetaceans & Sirenians – fibroelastic penis “We're talking about S-E-X in front of the C-H-I-L-D-R-E-N." – Maude Flanders "What?!?! Sex cauldron? I thought they closed that place down“ – Krusty the Clown

3. Sex Your Seal Ma’am? Teats & position of genital opening

4. I’m Too Sexy for my Dolphin Distance between Anal & Genital slit ♀ both within common groove ♂ separation between; testes internal cavity

5. Is that a manatee in your pocket..? Distance between Anal & Genital slit ♀ short distance ♂ separation between; testes internal cavity

6. Reproduction ↑ Fitness of female = ↑ Fitness offspring Females: cost of egg, pregnancy, lactation, postnatal care Males: invest energy in competition with other males (physical & sperm)

7. Reproduction Pinniped, Ursid, mustellid mating typically on land; some phocids shallow water

8. Reproduction Cetaceans – belly-to-belly

9. Reproduction Sirenians – belly-to-belly

10. Gestation Placental mammals – 18 days to 22-24 months Marine mammals: sea otter (6-7mo) to Sperm whale (16.5mo) ↑ Gestation time = ↑ Fetus size

11. Gestation Mass (kg) Gest.(mo) Int.(Y) Harbor seal11 9-121 N. Elephant 40 111 N. fur seal6 121 Walrus50 14-162-4 Porpoises8 8-11n/a Bottlenose20 12n/a Sperm Whale1050 14-163 Blue Whale2500 11-122-3

12. Gestation Mass (kg) Gest.(mo) Int.(Y) Manatee30 12-132-5 Dugongn/a 143-7 Sea Otter2 6-71 Polar Bear0.7 82-4

13. Delayed Implantation Delayed implantation – development of the blastocyst is slow or negligible Is obligate in pinnipeds, ursids, and mustelids Period of delayed implantation allows flexibility of timing of parturition, and is controlled by photoperiod

14. Delayed Implantation Dev.Gest(mo)Delay Impl.(mo) Harbor seal 8-9.5 1.5-3 N. Elephant 74 N. fur seal84 Walrus 10-11 4-5 Sea Otter4 2-3 Polar Bear44

15. Pinniped Reproduction

16. Pinniped Reproductive Cycle

17. Cetacean Reproductive Cycle

18. Change in latitude in grey whales Migration

19. Mating Systems High degree of variability in reproductive systems 2 major groups: polygyny & promiscuity Polygyny – successful male mating with several females Promiscuity – males associate with several females during a variable amount of time

20. Evolution of Polygyny

21. Mating Systems Driven by sexual selection – competition 1. Contest comp. – Direct comp. over ♀ 2. Endurance comp. – ♂ Endure longer 3. Scramble comp. – Search/locate ♀ 4. Mate choice comp. – Entice/attract ♀ 5. Sperm comp. - ↑ Quality/Quantity of sperm

22. Pinniped Mating Systems Male otariids typically utilize Resource Defense Polygyny Characteristics: 1. Males arrive before females 2. Females receptive close to place of birth 3. Rookery substrate stable but discontinous 4. Few aggressive interactions once dominance is established

23. Otariid Mating Systems Most males defend Territories – not females

24. Pinniped Mating Systems Male phocids typically utilize Female (Harem) Defense Polygyny Characteristics: Most dominant male (Alpha) defends females from other subordinate males

25. Phocid Mating Systems Most males defend Females – not Territories

26. Phocid Mating Systems Elephant Seals – High level polygyny – alpha controls large harems

27. Phocid Mating Systems Monk Seals – Low level polygyny – alpha controls individual females

28. Odobenid Mating Systems Walrus – either display a Female-Defense Polygyny (like Phocids) or a Lek-like behavior (similar to Otarriids)

29. Odobenid Mating Systems Lek - gathering of males, of certain animal species, for the purposes of competitive mating display

30. Cetacean Mating Systems Mysticetes – little social behavior beyond mother-calf pair Many utilize sperm competition – attempt to dilute out other males sperm Odontocetes – exist in groups of variable size for persist longer than any member’s life span

31. Odontocete Social Groups Arranged as schools, pods, or units Size varies by species & geographic location Mating structure a mixture of promiscuous & polygynous Male-male competition – sexual dimorphism

32. Spinner Social Groups Aggregate in schools of up to 100 individuals subgroups – up to 12 Subgroups travel in echelon formation

33. Orca Social Groups

34. Sperm Whale Social Groups Similar to orca groups Males leave pods and form juvenile groups Solitary adult males rove among female groups

35. Sirenian Mating Systems Similar to mysticetes- little social structure past mother-calf pairs Animals congregate into herds during summer months to breed Dugongs found in larger associations than manatees

36. Lactation Strategies Most energetically expensive aspect of reproduction Best interest to pass as much energy as possibly even at expense of future offspring 3 strategies: Fasting, Foraging Cycle, Aquatic Nursing

37. Fasting Lactation Strategy Example: Northern elephant seal Duration of fasting: All of lactation Duration of lactation: Short (4-weeks) Fat content of milk: High (55%) Pups forage during lactation: No

38. Foraging Cycle Lactation Strategy Example: Antarctic fur seal Duration of fasting: Variable (few days) Duration of lactation: Intermediate (4-months) Fat content of milk: Intermediate (40%) Pups forage during lactation: No

39. Aquatic Nursing Lactation Strategy Example: Walrus Duration of fasting: Short (hours-days) Duration of lactation: Long (2-3 years) Fat content of milk: Low (2-3%) Pups forage during lactation: Yes

40. Lactation Length(w) Fat% Prot.% Harbor seal3.4 509 N. Elephant 4 545-12 N. fur seal18 4214 Walrus100 14-325-11 Porpoise32 4611 Bottlenose76 1412-18 Sperm Whale100 15-358-10 Blue Whale24-28 35-5011-14

41. Length(w) Fat% Prot.% Manatee52 n/an/a Dugong78 n/an/a Sea Otter20-30 21-269-12 Polar Bear13017-369-13 Lactation

42. Got Milk!