Every factual claim on The Living Planet must be supported by a source. We rank sources in tiers and prefer the highest available tier for each claim.
Source tiers
Tier 1: primary or highly authoritative — IUCN Red List, GBIF, ITIS, government wildlife agencies, peer-reviewed papers, university research, museum and science institution publications, official zoo and aquarium newsrooms.
Tier 2: strong secondary — major conservation NGOs, Smithsonian, reputable science publications, Nature news.
Tier 3: use cautiously — general news sites, local news, blogs from known institutions, press releases.
Tier 4: avoid unless manually approved — random blogs, unsourced animal-fact sites, social media, AI-generated content farms, content with unclear authorship.
AZA-related sourcing
AZA-related coverage uses publicly accessible AZA materials, public facility newsrooms, and approved partner publications. We never imply endorsement that is not explicit in the source.
Reporting an issue
See a source that needs revisiting? Tell us.