The basic assumption in this group culture seems to be that an external object exists whose function it is to provide security for the immature individual.

An individual's actual maturity may not correspond to their chronological age, as immature individuals can exist at all ages.

Assessments of age based on skeletal remains are most likely to be fairly accurate with immature or young adult individuals.

The genus is known from disarticulated bones belonging to two immature individuals.

New Zealand has reported annual catches of 150-300 tons, mostly of immature individuals, from 1998 to 2003.

An immature individual will have a shorter bill and lighter upperparts.

The third is an immature individual of the organ-donating caste.

Adult individuals have five arms but small, immature individuals have six.

After being born, immature individuals instinctively climb up to the back of the mother and stay there until their first molt.

In addition, females and immature individuals will emit so-called "female calls" when angry.