COSEWIC, IUCN and other groups recognize the need for additional assessment tools. Specifically, there is a need to consider life-history variation amongst Wildlife Species. COSEWIC has developed the following guideline:

In addition to the quantitative guidelines, COSEWIC will base its assessment on the degree to which various life-history characteristics (e.g., age and size at maturity, dispersal strategy, longevity) affect extinction probability and the likelihood that the Wildlife Species is vulnerable to the Allee effects of density dependence.

All else being equal:

• Wildlife Species with delayed age at maturity tend to be at greater risk of extinction than Wildlife Species with early age at maturity;
• for indeterminately growing organisms (Wildlife Species that continue to grow after attaining maturity), larger Wildlife Species tend to be at greater risk of extinction than smaller Wildlife Species;
• Wildlife Species with low dispersal tend to be at greater risk of extinction than Wildlife Species with high dispersal; and
• Wildlife Species with non-overlapping generations tend to be at greater risk of extinction than Wildlife Species with overlapping generations.