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- Stallions exhibit seasonal changes in sperm production and sexual behavior during spring and summer
- Social status and herd composition influence androgen hormone levels in males (D'Souza-Anjo et al. 2017)
- Possibly affects male reproductive behavior
- Mare backs into stallion or stands in front of him to indicate receptivity
- Ears turned back but not flattened, lips relaxed
- May urinate
- Stallion may rest chin on mare's back to test willingness to stand
- Then rears and places his forelimbs in front of mare’s pelvis
- Mare's first conception
- At about 4 years of age
- As early as 2 years of age
- Mares remain fertile until 20 years of age
- 24 years of age is the record oldest age of giving birth
- Stallion testes do not descend until 2.5 to 3 years of age
- Delayed descent is also observed in onagers, wild asses, and zebras
- Immature males may be incapable of breeding due to subordination to older stallions/males or incompetent sexual behavior.
- Stallions generally begin copulation at 5 years of age.
- Continue copulation until over 30 years of age.
- Seasonally polyestrous.
- In North America, cycles begin in early spring and last 7-8 months.
- 1 foal per year
- Mares conceive right after delivering a foal
- Tend to wean the foal around 1 year
- If fail to conceive, continue nursing for several years
Gestation and Birth
- Approximately 11 months (320-343 days)
- Mares ready to foal leave herd to seek quiet place.
- Return probably coincides with heat (9 days after birth).
- Birth weight:~30 kg (66 pounds)
Early growth and development
- Foal remains with dam for first 2 years
- Day 1
- Stands, walks, trots
- Nibbles forage
- 1 week
- Grazes: eats hay and grain
- Solitary play
- Defensive kicking
- Eats adult feces
- 1 month
- 39% of time resting
- Begins playing with others in age group, older brothers and sisters
- 1 to 2 months
- Nursing declines from 8.5% to 2.4%
- Begins to leave mother’s side and interact with other foals
- Spends same amount of time feeding as an adult, begin drinking water
In the wild
- About 20 to 25 years
- Up to 32 years in very long-lived individuals (Amanda Lussier, personal communication, 2020)
Boyd & Houpt (1994)
Monfort et al. (1991)
SDZWA Library Links
Fact Sheet Index
Fact sheet index, San Diego Zoo Wildlife Alliance Library
Home page, San Diego Zoo Wildlife Alliance Library
Email the librarians at email@example.com