TABLE 3
Some Life-History Differences Between r and K Strategists


r-strategist

K-strategist

Family characteristics

Large litter size

Small litter size

Short birth spacing

Long birth spacing

Many offspring

Few offspring

High infant mortality

Low infant mortality

Little parental care

Much parental care

Individual characteristics

Rapid maturation

Slow maturation

Early sexual reproduction

Delayed sexual reproduction

Short life

Long life

High reproductive effort

Low reproductive effort

High energy utilization

Efficient energy utilization

Low encephalization

High encephalization

Population characteristics

Opportunistic exploiters

Consistent exploiters

Dispersing colonizers

Stable occupiers

Variable population size

Stable population size

Lax competition

Keen competition

Social system characteristics

Low social organization

High social organization

Low altruism

High altruism

Note. Modified from Pianka (1970, p. 593, Table 1) E. O. Wilson (1975, p. 101, Table 4-2), Eisenberg (1981, p. 442, Figure 156), and Barash (1982, p. 307, Table 13.1).