Asian Elephant (Elephas maximus) Fact Sheet: Reproduction & Development

Female urine contains a sex pheromone that increases before ovulation (African Elephant's pheromone differs)
Female emits loud infrasonic call when in estrus to attract males

• Important because receptive time may last one day; calls persist for 5 days
• Audible up to 4 km (2.5 miles) away

Bulls sniff female genitals and urine, place trunk tip into mouth:

• Jacobson's organ on roof of mouth detects presence of the sex pheromone

Prior to copulation, wrestle with intertwined trunks, bite each other’s necks, male attempts mounting
Females exercise some choice in mates by running away and/or not standing still

• Females in estrus prefer breeding with males in musth

Mounts last about 30 seconds
Mating and births occur any time during year; may peak during heavy rains in some regions
In managed care, estrus cycle lasts 13 to 14 weeks (if female is not pregnant)
Females who have conceived or with young may have 4 - 5 years between estrus cycles
Only one in five follicular cycles, each lasting 2-3 weeks, produce a fertile egg

Males can breed at any time, not only when in musth (Hindu for "intoxicated")

• Musth levels of testosterone in male up to 20 times higher than normal
• Musth lasts about 4 months in wild males
• Females prefer musth males

Reproductive Rate:

• Most females give birth for the first time at 16-17 years.
• In optimal habitats, calving intervals are 2.5-4 years. In less favorable conditions, calving intervals are 5-8 years.
• Cows can calve past age 50. Two elephants in managed care (Meennakshi and Tara) calved at 54 and 62 years, respectively.

  Gestation

• Lasts 18-22 months, the longest gestation period of any mammal

Birth

• Litter size: Usually one calf; rarely twins (structure of uterus allows births several weeks apart)
• Weight: 75-115 kg (165-254 lbs)
• Height: 75-100 cm (2.5-3.3 ft)
• Calves are very hairy compared to adults. Hairier than African elephant calves.

Infant (< 1 year old)

• Infants may have many female juvenile helpers - allomothers or "aunties" (great survival advantage)
• Helpers allow mother to feed and rest; important for lactation
• Can stand on feet shortly after birth
• Follow the mother in her daily routines within a few days
• During first three months develop motor skills
• Females attracted to young calves

Juvenile

• Females are attracted to young calves; often minister to their needs so mothers can spend more time feeding and resting, which are important for lactation
• Age of weaning 18 months to 3 years or longer
  • May be forced to wean when younger sibling is born
  • Around age of weaning, differences in sexes begin to appear
    • Females strengthen bonds with family
    • Males become more independent, leaving family for longer periods to feed, explore or play
• Initial period of rapid growth slows at about 5 years; decline in growth rate is greater for females than for males
• Females care for young of both sexes during 10-15 years of development until sexual maturity

Subadult

• Can be difficult to distinguish from juveniles
• No fixed age of puberty; may depend on available nutrition
• Males often seen away from herds
• Penis large, although subadult males are not reproductively active
• Females may exhibit swelling of mammae

Adult

• Age of sexual maturity varies depending on nutrition
  • Bulls 14-15 (as early as 9) years
  • Cows minimum age to breeding 14-15 years; usuall 18-20 (Shoshani & Eisenberg 1982; Sukumar 1989)
• Bulls may not mate until late teens or twenties due to social hierarchy
• Males are distinguishable by enlargement of head and distinct penis sheath; no testicles visible
• Females and males often hard to distinguish because female's clitoris is large
• Females have square backs
• Males continue to grow at continuous slow rate. Female growth plateaus between 15 and 30 years
• Males in wild enter musth around age 30

• Long-lived, even among terrestrial mammals (Lahdenperä et al. 2014)
• Managed care
  • Median life expectancy
    • 47.5 years (females) (AZA 2023)

• Calves preyed upon by lions, hyaenas, tigers
• Complications during birth
• Drought
• Accidental falls
• Bulls fighting in musth
• Killed by humans defending their crops or poaching
• Mortality in bulls much higher than in cows, mostly due to poaching and fighting
• May starve to death in old age when the last of their teeth falls or worn out

Allen (2006)
Alter (2004)
Langbauer (2000)
Moss (1990)
Shoshani & Eisenberg (1982)
Sukumar (1989, 1994)