Lecture 15

Question 1

requirements of mammals

Answer 1

• vertebrates
• neocortex
• fur or hair
• 3 middle ear bones
• mammary glands for feeding young (maternal behavior seen in 100% of mammalian species due to the production of milk)

Question 2

requirements of marsupials

Answer 2

• most marsupial mothers have a front pouch
• contains multiple teats
• lack a placenta

Question 3

marsupial maternal behavior: kangaroos

Answer 3

• highlight altricial young, resemble embryos
• stays in pouch feeding for about 9 months
• after leaving pouch it will return to be fed or carried
• embryonic diapause
• capable of producing multiple types of milk at the same time
• do not provide extensive maternal care (pouch provides)
• grooming
• don’t show retrieval behavior

Question 4

embryonic diapause

Answer 4

ability to freeze the development of an embryo

Question 5

marsupial maternal behavior: koalas, opossums

Answer 5

• some marsupials have young that cling to the mother for transport after leaving the pouch
• adaptation for survival, no retrieval behaviors
• no evidence of embryonic diapause in koalas

Question 6

monotreme maternal behavior: platypus

Answer 6

• only 2 egg-bearing mammals
• nest (burrow) building
• incubation (6-10 days), mother lays on top of eggs
• feeding (mammary glands under skin, no teats), basically sweat out the milk and babies lick at the fur
• leave the burrow around 4 months, born highly altricial

Question 7

monotreme maternal behavior: echidna

Answer 7

• following mating the female develops a pouch
• seek shelter by digging/adopting a burrow, lay an egg, move it into new pouch
• baby remains in pouch after hatching
• milk released from mammary glands (no teats)

Question 8

eutherian (placental) mammals

Answer 8

• more stable/reliable habits
• longer gestations and more developed young

Question 9

three patterns of maternal care in eutherian mammals

Answer 9

1. altricial
2. precocial
3. semi precocial

Question 10

altricial species

Answer 10

dogs, carnivores, most rodents, insectivores

Question 11

behaviors of altricial species

Answer 11

• nest building prior to birth
• afterbirth some animals show placentophagia
• cleaning behavior
• nursing
• huddling
• grooming
• offspring retrieval
• aggression towards intruders

Question 12

altricial pup-directed behaviors

Answer 12

• grouping
• huddling
• retrieval
• licking/grooming
• feeding

Question 13

altricial non-pup directed behaviors

Answer 13

-nest building
- placentophagia
- protection

Question 14

precocial species

Answer 14

deer, cows, horses, “hider types” that hide their babies

Question 15

behaviors of precocial species

Answer 15

• offspring hidden at nest site away from group
• mother spends most of the time away but returns to nurse
• after short time (7-10 days) the young follow the mother, “follower type” animals like giraffes

Question 16

semiprecocial species

Answer 16

humans, other primates

Question 17

behaviors of semiprecocial species

Answer 17

• essentially helpless but can cling to mother
• humans can thermoregulate
• some will alternate between carrying the young and placing them in a nest or crib
• some will leave them in a nest for longer periods in the beginning

Question 18

paternal behavior

Answer 18

• rare in mammals (3-5% of species)
• seen in primates, carnivores, rodents

Question 19

California mice parental behavior

Answer 19

• pair-bonded, monogamous mice
• assist in nest building
• carry young
• groom
• anogenital licking

Question 20

concaveation

Answer 20

introduce pups of differing ages and observe if/when parental behavior will be seen

Question 21

pup retrieval experiment

Answer 21

• virgin rats = no retrieval practices shown
• experienced rats = retrieval practices shown
• experienced virgin rats = slower retrieval shown after living with post-birth mother and pup for 4 days

Question 22

hormonal correlates of mammalian parental behavior

Answer 22

• prolactin
• placental lactogen
• estrogens
• progesterone
• CCK
• oxytocin
• prostaglandins
• relaxin
• B-endorphins

Question 23

hormonal profile in humans

Answer 23

• oxytocin and B-endorphins increase around parturition
• prolactin typically high during pregnancy and following birth

Question 24

induction of maternal behavior: transfusion

Answer 24

a nulliparous rat receiving blood transfusion from a new mother showed the onset of maternal behavior in about 24 hours

Question 25

induction of maternal behavior: hysterectomy

Answer 25

- terminate pregnancy at different stages to induce maternal behavior - early and mid pregnancy rats will typically not show maternal behavior to foster pups - hysterectomies between days 16 and 19 of gestation resulted in the onset of maternal behavior 24-48 hours following surgery - probably due to removal of placenta - leads to corpus lutea regression = less progesterone - removes gonadotropins that suppress ovarian estrogen production = increased estradiol

Question 26

induction of maternal behavior: rabbits

Answer 26

- near parturition doe builds nest and lines it with her fur - dopamine agonists (block prolactin release) = prevent nest building - treatment with prolactin restores nest-building - a nulliparous rabbit treated with E (18 days) and P (days 2-15) will show nest-building behavior - nest-building behavior close to parturition requires high E, P, and prolactin

Question 27

progesterone and maternal behavior

Answer 27

- role not clearly defined - appears to be biphasic for maternal behavior 1. it acts in early pregnancy (with estrogen) to facilitate subsequent maternal behaviors 2. needs to be withdrawn close to parturition for maternal behavior to be seen