Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts. Experimental study: At least one thing in the experiment was changed to see if it had an impact on the subjects ...

Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts. Meta-analysis: This type of study involves using statistics to combine the data from multiple previous studies to ...

Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts. Sulfur-crested cockatoos in western Sydney have learned to use twist-handle water fountains to drink, according ...