Utheria

Age at first birth

This is the age at which females give birth to their first litter. Note that this includes any delays in reproduction as it just records the age of the female at her first birth. Birth is defined as infants existing independent of the female’s internal system according to the following criteria:

• Eutherians — birth.
• Metatherians — either when the young leave the mothers birth canal or the start of the period of teat attachment (both of which will occur nearly simultaneously).
• Monotremes — egg hatching.

Generic value types: Data Value, Data Range, Measure, Sample Size, Captivity Status, Units and Source Type.