African and Asian Lions (Panthera leo) Fact Sheet: Reproduction & Development

Signaling reproductive receptivity

• Courtship initiated by either female or male (Wilson and Mittermeier 2009)
• In close association during the mating period ("consorting") (Schaller 1972; Wilson and Mittermeier 2009)
  • Usually within 1-3 m of each other while consorting
• Female in estrus exhibits restlessness (Schaller 1972)
  • Lies down, jumps up, and walks rapidly
  • Rolls and twists on her back
• Male follows female at all times (Schaller 1972; Wilson and Mittermeier 2009)
  • Rests with her
  • May lick her neck, back, or rump
    • Uncommon behavior outside of courtship
  • Female may not accept male’s advances or may playfully avoid
• Flehmen: male smells female’s urine or vulva to assess receptivity (Schaller 1972; Estes 2012)
  • Wrinkles nose with mouth open and eyes closed (“grimace” facial expression)

Mating

• Continues for a period of approximately 3-4 days (Packer and Pusey 1983; West and Packer 2013)
• Female invites copulation by lordosis, a reflexive behavior in felids (Wilson and Mittermeier 2009)
  • Female may have some choice over paternity of offspring (West and Packer 2002)
  • Male may also initiate copulation (Schaller 1972)
• Mating occurs over several hours or over the course of a night (Wilson and Mittermeier 2009)
  • Copulations are brief but frequent
    • Last a minute or less
    • Occur as often as every 15 minutes (Wilson and Mittermeier 2009) or three times per hour (West and Packer 2013)
  • Between copulations, the pair walks or lies down together
• Behaviors during copulation
  • Female purrs loudly or emits a deep growl (Schaller 1972; Wilson and Mittermeier 2009)
    • Facial expression suggests aggression
  • Male often licks and gently bites female’s neck (Schaller 1972; Wilson and Mittermeier 2009)
    • Common in cats
    • Probably induces passivity in female
    • Male must show restraint while biting or may kill female
  • Ends with male growling or yelping and female turning to snarl as male dismounts (West and Packer 2013)
  • Contact ends abruptly after copulation (Schaller 1972; Wilson and Mittermeier 2009)
• Fights between males uncommon
  • Coalition males tolerated nearby, but strange lions driven off (Schaller 1972; Wilson and Mittermeier 2009)
• Some coalition males fail to breed successfully (Wilson and Mittermeier 2009)
  • Many coalitions show dominance relationships
    • Only one or a few males father offspring (Packer et al. 1991)
  • Offset by kin selection
    • Non-breeding helpers still benefit
• Majority of mating interactions do not result in pregnancy (Wilson and Mittermeier 2009)
  • Conception rates: 20-40% in lions

Effects of social structure on paternity

• Lyke et al. (2013) report a high percentage of lions in Etosha National Park having extra-group paternity
  • Females conceive by males outside their pride
  • Pride social structure may not represent breeding structure
  • Higher occurrence of extra-group paternity in prides with a lower sex ratio
    • Small number of males may not be able to monopolize all available females

Intruder males kill cubs to induce estrus in females

• Common when new “intruder” males take over a pride (Wilson and Mittermeier 2009)
  • Male coalitions only hold pride tenure for 2-3 years
• Assures males of their paternity (Wilson and Mittermeier 2009)
  • Death of litter brings females back into estrus
  • Allows new males to have their own offspring born in about 8 months, vs. up to 18 months if females were allowed to wean current cubs
• Huge loss of reproductive investment for females (West and Packer 2013)
• Females defend cubs, often unsuccessfully (Wilson and Mittermeier 2009)
  • Many lose cubs within a month of takeover (Wilson and Mittermeier 2009)
    • Geographic variation in rates of infanticide (Paul Funston, personal communication, 2016)
      • Frequent in Serengeti
        • More than 1/4 of all cubs are killed by invading males (Sunquist and Sunquist 2002)
      • Less frequent in other areas
    • Males chase out other, less dependent young
  • Pregnant females lose newborns shortly after birth (Wilson and Mittermeier 2009)
  • Lionesses may be killed trying to defend their cubs (Packer and Pusey 1983)
  • Also see Aggression
• Females more sexually active for about 3 months after a takeover (Wilson and Mittermeier 2009, except as noted)
  • Attract other males; encourage competition
    • Promotes the fittest male coalition gaining tenure over the pride
  • Infertile ‘testing period’
    • May increase female lifetime reproductive success (Packer and Pusey 1983)
  • When tenure is stable, synchronous breeding resumes
  • Females resume regular estrus cycles, but females that lost cubs often have reduced fertility (Packer and Pusey 1983)
  • Conception following infanticide
    • Mating success is low
    • Protracted mating period to reinforce social bonds
    • Females conceive an average of 102 days after takeover (Packer and Pusey 1983)

Breeding cycle

• Breeding
  • Occurs throughout the year (Wilson and Mittermeier 2009)
  • Not clear whether ovulation is induced or spontaneous (West and Packer 2013)
  • Spontaneous ovulation observed in managed care
• Estrous cycle
  • Lasts 16 days (Wilson and Mittermeier 2009; West and Packer 2013)
• Estrus
  • 4-7 days with a two week interval (Packer and Pusey 1983)
• Generation length
  • About 7 years (Packer et al. 1998; Bauer et al. 2016)

Gestation

• Age of first parturition
  • About 3.5 years (43 months) (Packer et al. 1998; Daigle et al. 2015)
• Maximum age at last parturition
  • Estimated 15 years (Packer et al. 1998)
• Pregnancy
  • 110 days, on average (Wilson and Mittermeier 2009)
    • Range: 100-114 days (15-16 weeks)
• Litter size (number of cubs)
  • Average 2.5-3; range 1-6 (Packer and Pusey 1995; Wilson and Mittermeier 2009)
  • 89% of litters: 1-4
• Sex ratio
  • Generally 1:1 (Packer and Pusey 1987)
  • May be slightly male-biased after a pride takeover (Packer and Pusey 1987)
  • Some reports of female-biased subpopulations (e.g., C. Packer, personal observations, in West and Packer 2013; also, Smuts et al. 1978)
• Inter-birth interval
  • With surviving cub(s) (Wilson and Mittermeier 2009)
    • 20 months
    • Range: 11-25 months
  • With loss of litter
    • 4-6 months (Pusey and Packer 1987; Wilson and Mittermeier 2009)
  • Births are synchronized by male takeovers (Wilson and Mittermeier 2009)
    • Higher survival rates in litters born synchronously
    • Tend towards a male-biased sex ratio

Birth

• Females leave pride for 4-8 weeks (Wilson and Mittermeier 2009)
• Birth peaks (West and Packer 2013)
  • Reported in some locations, but not geographically uniform
  • Possibly timed to when prey species also having young
• Infant characteristics
  • Mass at birth: 1.5 kg (2.2 lbs), on average (Wilson and Mittermeier 2009)
  • Eyes open at birth or shortly after birth (West and Packer 2013)
  • Fur is spotted (Schaller 1972)
• Birth occurs in a den or dense brush (Wilson and Mittermeier 2009)
  • Protection for newborn cubs
  • Female remains close to den
• Female’s home range expands when young are mobile
  • Leaves cubs to search for food, but returns as often as possible
• Cubs rely on milk until approximately 4-6 weeks of age (Schaller 1982)
  • Weaned by 8 months
• Cubs kept hidden until more mobile and beginning to eat meat (West and Packer 2013)
• Females rejoin pride with 4-8 week old cubs (Wilson and Mittermeier 2009; West and Packer 2013)
  • Cubs ‘pooled’ to form a crèche
    • Usually 4-10 cubs, but may be more than 25 cubs
    • Mothers spend most of their time together
    • In very large crèches, young cubs must compete with larger, older cubs
      • Youngest cubs have highest mortality
      • Females with new cubs less likely to join

• Expectant mothers withdraw from their pride to give birth (Schaller 1972)
• Remain separate from pride members until cubs are 6-8 weeks old
• Mother suckles, guards, and transports cubs during first two weeks of life (Schaller 1972)
• Hides cubs until mobile at 4-6 weeks of age
• Moves by picking cubs up by back of their necks
• Induces passivity
• Cubs hang loosely without moving
• Mother and cubs rejoin pride around 6-8 weeks (Schaller 1972)
• Cubs then raised communally (“alloparenting”) (Pusey and Packer 1994)
• Communally nurse cubs
• All lactating lionesses typically participate
• Cubs suckle from any lactating female, though females try to give milk primarily to their own young (Pusey and Packer 1994)
• Nursing
• Milk has high fat content (see de Waal (2004) for milk composition details)
• Increases energetic demands on mother (Wilson and Mittermeier 2009)
• Mother compensates with increased hunting activity
• Leaves cubs alone for extended periods while hunting (Schaller 1972)
• Mother begins to decrease milk production prior to cubs reaching 7 months of age (Schaller 1972)
• After weaning
• Mother shows cubs where kills have been made (Schaller 1972)
• Calls over with soft grunts
• Role of males
• Provide indirect benefits (Schaller 1972)
• Protection
• Help cubs get enough to eat
• Females may hungrily deny cubs access to kills

For a detailed visual and descriptive guide, see Karyl L. Whitman’s and Craig Packer’s A Hunter’s Guide to Aging Lions in Eastern and Southern Africa.

Infants: birth to 1 year

• Birth (Schaller 1972; West and Packer 2013)
• Born almost helpless
• Eyes open at birth or shortly after birth
• Development (Schaller 1972, except as noted)
• Walking steadily by 3 weeks
• Milk teeth erupt
• Incisors at 3 weeks
• Canines at 4 weeks
• Eyes change from gray-blue to amber at 2-3 months
• Acquire adult coat around 3-5.5 months
• Faint spotting on legs and sides may persist into adulthood
• No tail tuft at birth
• Develops at 5-7 months
• Mane of males begins to grow around 6-8 months (Rudnai 1973; West and Packer 2013)
• Often delayed in warmer climates
• Diet: transition from milk to meat
• Subsist on milk for 6-7 weeks (Wilson and Mittermeier 2009; West and Packer 2013)
• Gradual transition to meat diet starting at 4-6 weeks of age (Schaller 1972)
• Milk supplemented with meat
• Suckle less after 7 months
• Fully weaned by 12 months (Wilson and Mittermeier 2009)
• Weaned cubs may steal milk from lactating females for up to 12 months (Pusey and Packer 1994; West and Packer 2013)
• Mortality
• Common causes: infanticide (or abandonment after takeover), starvation, and disease (West and Packer 2013)
• Females may also kill cubs of unfamiliar lions
• On average, 60% of cubs die within the first year of life (West and Packer 2013)
• Higher in some locations (e.g., Serengeti and Kruger National Parks)
• After reaching one year, mortality declines to less than 20% (Packer et al. 2001)

Large Cubs: 1-2 years

• Cubs grow rapidly in first 1-3 years (Wilson and Mittermeier 2009)
• Growth spurt after permanent canines develop (Schaller 1972)
• Remain with mother for 21-30 months (Wilson and Mittermeier 2009)
• Still dependent on mother for food until 1.5-2 years of age (Schaller 1972)
• Deciduous teeth replaced with permanent teeth by 2 years of age (White et al. 2016)
• Except canines, which erupt by 3 years of age
• Weight at 2 years of age (Schaller 1972)
• Females
• About 2/3 the size of an adult female
• Males
• Larger than female cubs, 90-100 kg (198-220 lbs)
• Males develop short mane crest and hair tufts on cheeks, neck, and chest (Schaller 1972)

Subadults: 2-4 years

• Physical development (Schaller 1972)
• Females
• Height and length may be similar to adult female
• Build more slender and muzzle shorter than adult females
• Males
• Traits (Miller et al. 2016)
• Few facial scars
• Tight jowl
• Hair growth on neck, chest, shoulder, etc.
• Teeth begin to yellow and show signs of wear
• Nose pigmentation darkens
• Growth spurt around 3-3.5 years old; lasts about 6 months
• Close to reaching adult size and weight
• Mane growth varies
• Behavioral development
• Stay with mother and pride a long time to improve their hunting skills (Wilson and Mittermeier 2009)
• Must learn
• Which prey are appropriate
• How to time an attack (not rush prey too soon)
• By 2 years of age, lionesses are competent hunters (Sunquist 2002)
• Begin to disperse as they reach sexual maturity (Wilson and Mittermeier 2009, and as noted)
• Males generally leave natal area at 2-3 years of age
• Females generally stay in or near their natal area, but leave birth pride
• Occupy a portion of their mother’s home range or an adjacent area (West and Packer 2013)
• Provides daughter cubs access to good foraging areas and familiar hunting sites
• Also, possibly protection from aggressive animals and knowledge of den sites
• May be forced to leave by new males taking over pride (Hanby and Bygott 1987)

Sexual maturity

• Varies among habitats
• Maturity sometimes delayed in harsher regions (Funston et al. 2003; West and Packer 2013)
• Example: first conception by females
• Serengeti National Park: 30-38 months (Packer et al. 1988)
• Kruger National Park: as long as 48 months, on average (range 40-60 months) (Funston and Mills 1997; West and Packer 2013)
• Males mature at about 26 months (Wilson and Mittermeier 2009)
• But, generally do not father cubs until about age 5 when hold pride tenure and have mating opportunities
• Youngest territorial male reported: 5 years old (West and Packer 2013)
• Oldest territorial male reported: 11 years old (West and Packer 2013)
• Females first become pregnant at about 43 months (3.5 years) old (Wilson and Mittermeier 2009)

Young Adults: 4-6 years

• Physical development (Schaller 1972; see Miller et al. 2016)
• Both sexes continue to grow until about 6 years of age
• Males
• Mane grows and reaches full size
• Color usually brownish with dark reddish, yellow, or black hairs
• Sometimes, hair tufts at elbows
• Light facial scarring
• Nose is 40-70% black

Adulthood: 6 years and older

• Physical characteristics
• Teeth severely worn or broken by 10 years of age (White et al. 2016)
• Older males usually with short, scruffy manes (Schaller 1972)
• Some retain full, longer mane
• Some facial scarring (Miller et al. 2016)
• Teeth yellow with greater signs of wear (Miller et al. 2016)
• Some with slack in jowls (Miller et al. 2016)
• Reproductive senescence
• Females
• Declining maternity rates at about 14 years of age (Packer et al. 1998)
• Reproductive until about 15 years of age (Packer et al. 1998)
• Most stop after age 15 (Smuts et al. 1978; Whyte and Smuts 1988; West and Packer 2013)
• Males
• Probably cease fathering offspring after pride tenure is lost (Schaller 1972; Wilson and Mittermeier 2009)
• Likely physiologically capable of producing viable sperm beyond this age

Wild populations

• Typical life expectancies unknown
• Females
  • Few live past 18 years of age (Packer et al. 1998; West and Packer 2013)
• Males
  • Shorter-lived than most females
  • Rarely reach 16 years (Smuts et al. 1978; Whyte and Smuts 1988; West and Packer 2013)

Managed care

• Median life expectancy
  • 16.9 years (AZA 2023)
• Longer than in the wild (West and Packer 2013)

Causes of mortality (Schaller 1972)

• Illness, disease
• Starvation
• Abandonment
• Old age
• Fights
• Accidents
  • Buffalo and elephant occasionally gore or trample lion cubs
• Predators (cubs)
  • E.g., leopards, hyenas, other lions

Cub mortality

• Highest in first year (West and Packer 2013)
  • Averages 60%
  • Causes: infanticide, abandonment, starvation, disease
  • Competition may increase mortality after the first year (Packer et al. 2001)
• Declines to less than 20% after one year of age

Ten-day-old cubs at the San Diego Zoo Safari Park.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Lion cubs with their mother, Oshana, leave their nursery den—for the first time—to explore and play.

Oshana gave birth to these cubs at the San Diego Zoo Safari Park on June 22, 2014.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.