Parental CareParental Care

Christel Moons

What is parental care?What is parental care?

Parental care (or parental investment)

= Any behavior towards offspring that increases the chances of the offspring’s survival at the cost of the parent’s ability to invest in other offspring

Advantage of parental care?Advantage of parental care?

Offspring: survivalParent: evolutionary advantage

– Contributes to reproductive fitness

– Fitness = The relative ability of an organism to survive and leave offspring that themselves survive and leave offspring

Disadvantage of parental Disadvantage of parental care?care?

Expensive to provide parental care– Staying close to the young ( new mating)– At the expense of own survival rates

Foraging for food that mainly goes to offspring Presence of young attracts predators

Hypothesis by David Lack: (trade-off)

There is a cost of reproduction that forms some sort of limit on how much an animal can do to

provide care to its offspring

The imbalance between the The imbalance between the sexessexes

Animal kingdom: Females provide most or all of parental care Resulting from evolutionary imbalance

– Females invest more in conception, gestation, parturition

– Males provide ‘cheap’ sperm, take no part in gestation, parturition

– Exceptions to the rule: e.g. Stickleback, Sea Horse

Maternal care in mammalsMaternal care in mammals

Altricial mammals– Deaf, blind– Deficient in motor control and temperature regulation– Need:

Nursing Warm nest Retrieved into the nest

– Parental care: Lick offspring for defecation/urination; defensive

Characteristics of newborn Characteristics of newborn mammals (cont.)mammals (cont.)

Precocial mammals (Ungulates)– More motory and sensory mature (large groups,

migrating in search for food)– Need:

Fast drying after birth Nursing

– Parental care: No nest building Encouraging first attempts at standing/walking and nursing Selective, individual bond with foal (recognition in herd)

Maternal care in Maternal care in horseshorses

First mare-foal interactionFirst mare-foal interaction

Gestation: 315-365 days (average=340)Parturition = act of giving birthAfter parturition:

– Mare licks fetal membranes– = Process to become familiar rather than

cleaning– Olfactory cues !!!– Primary socialization established within 2 hrs.– Separation extreme anxiety + disorientation

by the foal

First mare-foal interactionFirst mare-foal interaction(cont.)(cont.)

Foal develops motor/auditory/tactile skills fast– Foal initially follows any large object– Gradually learns ‘correct object’

First nursing attempt after standing:– Standing: within 60, up to 120 minutes after birth

– Fillies vs. Colts

– Nursing: 30 – 120 minutes after birth ‘air sucking’ Nursing position = reverse parallel Bunting

Indicators of maternal careIndicators of maternal care1. Proximity

– Distance between mare and foal– On pasture < 5 m on day 1– Due to foal behavior, even when lying down– Very little physical contact– Recumbency response:

“when her foal lies down, the mare stops engaging in any other activity and stays near her young, by instinct on alert for predators, even though there may be no such dangers anywhere near”

– Trends with age

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

2. Nursing – Definitions (research-based):

1979: The time a foal first nuzzled the mare’s udder for 3 seconds until the final time the foal removed its head from the medial side of the mare’s hind limb

1980-81: Start of a nursing bout was recorded when the foal actually sucked for the first time

1983: A period of nursing activity delimited by intervals of non-nursing activity lasting for 27 secs

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

– Definitions (cont.): 1992: Including pre-nurse nuzzling, sucking, intra-

bout pauses and intra-bout nuzzling

1994: Including pre-suck nuzzle, pre-suck pause, suck, intra-suck nuzzle and intra-suck pause

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

Functions of nursing:

Nourishment

Initial passive transfer of immunity (Colostrum)

Comfort Behavior

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

Nursing Behavior

– Initiation of nursing:By mareBy foal

– Crossing the bow

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

Nursing Behavior– Nursing bout frequency and duration

Frequency(per hour)

Belgian draft horses

9

Draft + mule foals

14

Welsh ponies

4

Duration: 78 – 84 seconds

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

Nursing bout termination– Constant individual differences between foals– Mares < Foal– Termination by foal:

Remove head from udder Walk away

– Termination by mare (Welsh ponies): Walk away Kick at abdomen Lift hind limb to obstruct nursing Direct aggression against foal

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

3. Aggression– Rare during first month; nursing related– Different forms:

Laying back of ears Bite threat Bite Kick threat Kick Squeal Bunt Tail swish

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

– Response from foal No discernable response Short pause in nursing Aggressing back at the mare

Indicators of maternal careIndicators of maternal care (cont.) (cont.)4. Other interactions

• Mutual grooming = Reciprocal coat care in which the partners

nuzzle and chew on one another’s coatFillies () groom about twice as much as

colts () do

Indicators of maternal careIndicators of maternal care(cont.)(cont.)

4. Other interactions

• Play3 major types of play: general motor,

interactive, and object manipulationIn stall: foal explores environment by mouthing

parts of stall, mare’s tail/ear/halterOn pasture: Galloping away from the mare in

what appears to be thrill-seaking behavior