Missing means missing
Unavailable measurements are shown as unavailable instead of being estimated for visual completeness.
Data transparency
SpeciesTraits Data Methodology
How SpeciesTraits stores, standardizes, and displays animal life-history records, including the distinction between maximum longevity and average lifespan.
Sources
Dataset-backed records
SpeciesTraits currently imports structured life-history records from the Amniote Life History Database and AnAge where available. Source-specific evidence fields are retained in the SpeciesTraits data model so that measurements can remain tied to their dataset context.
Species profile pages present standardized fields for comparison. The site does not manufacture replacement values when a measurement is missing.
Definitions
Core traits
- Maximum longevity
- The longest recorded age stored for a species. It is not the same as average lifespan, median lifespan, or life expectancy.
- Gestation / incubation
- Gestation is used when a pregnancy duration is recorded; incubation is used for egg development. They remain separate stored fields even when compared in one interface dimension.
- Age at maturity
- Maturity can be stored as unsexed, female, or male. For comparable display, SpeciesTraits uses an available maturity record rather than inventing a missing one.
- Adult body mass
- Adult body mass is stored in grams and displayed in a more readable unit when appropriate.
- Litter / clutch size
- A shared comparison field for the number of offspring or eggs associated with a reproductive event.
Handling rules
How values are presented
Comparable display units
Stored day, year, gram, and offspring values are formatted into readable units without changing the underlying meaning of the field.
Profiles and Explorer
Species pages provide detailed context, while the Explorer compares the same standardized trait fields across available records.
Important longevity note
When SpeciesTraits says maximum longevity, it means a longest-recorded value from the available data. It should not be described as the species' “average lifespan” unless a separate source specifically provides an average.